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Hindawi Publishing CorporationJournal of Electrical and Computer EngineeringVolume 2013 Article ID 892628 20 pageshttpdxdoiorg1011552013892628

Research ArticleAn Overview of the HomePlug AV2 Technology

Larry Yonge1 Jose Abad2 Kaywan Afkhamie1

Lorenzo Guerrieri3 Srinivas Katar1 Hidayat Lioe4 Pascal Pagani5

Raffaele Riva6 Daniel M Schneider7 and Andreas Schwager7

1 Qualcomm Atheros 203 East Silver Springs Boulevard Ocala FL 34470 USA2 Broadcom Corporation Llacuna 56ndash70 8th Floor Building A 08005 Barcelona Spain3 DORA SpA STMicroelectronics Group Via Lavoratori Vittime del Col Du Mont 28 11100 Aosta Italy4Marvell Semiconductors 5488 Marvell lane Santa Clara CA 95054 USA5Orange Labs Networks 2 Avenue Pierre Marzin 22300 Lannion France6 STMicroelectronics Srl Via Olivetti 2 20864 Agrate Brianza Italy7 Sony Hedelfinger Straszlige 61 70327 Stuttgart Germany

Correspondence should be addressed to Pascal Pagani pascalpaganiieeeorg

Received 3 August 2012 Accepted 21 November 2012

Academic Editor Andrea M Tonello

Copyright copy 2013 Larry Yonge et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

HomePlug AV2 is the solution identified by the HomePlug Alliance to achieve the improved data rate performance required by thenew generation of multimedia applications without the need to install extra wires Developed by industry-leading participants inthe HomePlug AV Technical Working Group the HomePlug AV2 technology provides Gigabit-class connection speeds over theexistingACwires within home It is designed tomeet themarket demands for the full set of future in-homenetworking connectivityMoreover HomePlug AV2 guarantees backward interoperability with other HomePlug systems In this paper the HomePlug AV2system architecture is introduced and the technical details of the key features at both the PHY and MAC layers are described TheHomePlug AV2 performance is assessed through simulations reproducing real home scenarios

1 Introduction

The convergence of voice video and data within a varietyof multifunction devices along with the evolution of HighDefinition (HD) and 3-Dimensional (3D) video are todaydriving the demands for home connectivity solutions Homenetworks are required to support high throughput connec-tivity guaranteeing at the same time a high level of reliabilityand coverage (the percentage of links that are able to sustaina given throughput in two-node or multinode networks)Applications such as HD Television (HDTV) Internet Pro-tocol Television (IPTV) interactive gaming whole-homeaudio security monitoring and Smart Grid managementhave to be supported by the new home networks

During the last decade in-home power line communica-tion (PLC) has received increasing attention from both theindustry and research communities The reuse of existing

wires to deploy wide band services is the main source ofattractiveness of the in-home PLC technologies Anothermajor advantage of PLC is the ubiquity of the power lineswhich can be used to provide whole-home connectivitysolutions However the power line medium has not beenoriginally designed for data communication the frequencyselectivity of the channel and different types of noise (back-ground noise impulsive noise and narrow band interferers)make the power line a very challenging environment andrequire state of the art design solutions

In 2000 the HomePlug Alliance [1] an industry-ledorganization was formed with the scope to promote powerline networking through the adoption ofHomePlug specifica-tions In 2001 theHomePlugAlliance released theHomePlug101 specification followed in 2005 by a second release namedHomePlug AV [2]The letters ldquoAVrdquo abbreviate ldquoAudio VideordquoHPAV rapidly became the most widespread adopted solution

2 Journal of Electrical and Computer Engineering

for in-home power line communication To meet the futuremarket needs in January 2012 the HomePlug Alliance pub-lished the HomePlug AV2 specification [3] HomePlug AV2enables Gigabit-class connection speeds by leveraging on theexisting power line wires while remaining fully interoperablewith other technologies for in-home connectivity (HomePlugAV [2] HomePlug Green PHY [4] and IEEE 1901 [5]) TheAlliancersquos AV Technical Working Group (AV TWG) definednew features at both the PHY and MAC layers These havebeen introduced in theHomePlugAV2 specification based onextensive field tests conducted in real home scenarios acrossdifferent countriesThe field results obtained by the AVTWGvalidated the HomePlug AV2 claimed performance both interms of achievable data rate and coverage

In this paper we highlight the key differentiating Home-Plug AV2 features compared to the HomePlug AV technol-ogy At the physical (PHY) layer HomePlug AV2 includesthe following (i) Multiple-Input Multiple-Output (MIMO)signaling with Beamforming to offer the benefit of improvedcoverage throughout the home especially on highly atten-uated channels MIMO enables HomePlug AV2 devices totransmit on any two-wire pairs within three-wire configura-tions comprising Line (L) Neutral (N) and Protective Earth(PE) (the coupling is done in the MIMO Analog Front End(AFE) blocks in Figure 1) (ii) Extended Frequency Band upto 86 MHz to increase the throughput especially at the lowto mid coverage percentages (part of IFFTFFT (1024 8192)andMapper blocks in Figure 1) (iii) Efficient Notching allowstransmitters to create extremely sharp frequency notches IfElectromagneticCompatibility (EMC) regulationwill requirea fragmented communication spectrum the throughput lossby excluded frequencies can be minimized (part of PowerAllocation and Window and Overlap blocks in Figure 1)(iv) Power back-off to increase the HomePlug AV2 datarate while reducing the electromagnetic emissions (part ofPower Allocation blocks and the AFEs in Figure 1) (v) EMCFriendly Power Boost to optimize the transmit power bymonitoring the input port reflection coefficient (known as the11987811

parameter) at the transmitting modem (vi) AdditionalPHY Improvements comprising higher order QuadratureAmplitude Modulation (4096-QAM) (part of Mapper andDemodulator blocks in Figure 1) higher Code Rates (89code rate) (part of Turbo Convolutional Encoder in Figure 1)and smaller guard intervals (part of Cyclic Prefix blocks inFigure 1) to assist better peak data rates At the MediumAccess Control (MAC) layer HomePlug AV2 includes thefollowing (i) Power Save mode to improve energy efficiencywhen the device is in standby (ii) Short Delimiter to reducethe overhead of the transmission shortening the Preambleand Frame Control symbols (iii) Delayed Acknowledgementsto increase the overall transmission efficiency by reducing theInter Frame Spacings (iv) Immediate Repeating to expand thecoverage by repeating the signal on paths with better Signalto Noise Ratio (SNR) characteristics

All the features listed above improve the Quality ofService of AV2 power line modems by improving coverageand robustness of communication links

The following sections provide technical details for all theabove mentioned features Moreover the AV TWG evaluated

the performance of the HomePlug AV2 systemThe adoptionof all the above listed features provides a significant gain ofHomePlug AV2 compared to HomePlug AV The remainderof this paper is organized as follows Section 2 presentsthe overall HomePlug AV2 system architecture precededby a brief overview of the HomePlug AV technology Thenew PHY and MAC layer technical features are detailed inSections 3 and 4 respectively Section 5 explains how thetechnology coexistence is dealt with Section 6 summarizesthe performance gain of HomePlug AV2 compared to Home-Plug AV and Section 7 concludes this introduction to theHomePlug AV2 technology

2 System Architecture

21 A Brief Overview of HomePlug AV HomePlug AVemploys PHY and MAC technology that provides a 200-Mbps class power line networking capability The PHYoperates in the frequency range of 2ndash28MHz uses windowedOrthogonal Frequency Division Multiplexing (OFDM) anda powerful Turbo Convolutional Code (TCC) that providesrobust performance within 05 dB of Shannonrsquos limit Win-dowed OFDM provides more than 30 dB spectrum notchingOFDM symbols with 917 usable carriers (tones) are usedin conjunction with a flexible guard interval Modulationdensities from BPSK to 1024 QAM are adaptively applied toeach carrier based on the channel characteristic between thetransmitter (Tx) and the receiver (Rx)

On the MAC layer HomePlug AV provides a Quality ofService (QoS) connection oriented contention-free serviceon a periodic TimeDivisionMultiple Access (TDMA) alloca-tion and a connectionless prioritized contention-based ser-vice on a Carrier Sense Multiple AccessCollision Avoidance(CSMACA) allocation The MAC receives MAC ServiceData Units (MSDUs) and encapsulates them with a headeroptional Arrival Time Stamp (ATS) and a checksum to createa stream ofMAC framesThe stream is then divided into 512-octet segments encrypted and encapsulated into serializedPHY Blocks (PBs) and packed as MAC Protocol Data Units(MPDUs) to the PHYunitwhich then generates the final PHYProtocol Data Unit (PPDU) to be transmitted onto the powerline [2]

HomePlug AV2 enhances significantly the capabilityabove to accommodate new generation of multimedia appli-cations with Gigabit performance

22The HomePlug AV2 Technology TheHomePlug system isspecified for in-home communication adapted to the powerline channel The in-home communications are establishedwith Time Division Duplexing (TDD) mechanism to allowfor symmetric communication between peers as opposedto the classical access system in ADSL with two differentdownstream and upstream throughputs

The PHY layer employs OFDM modulation scheme forbetter efficiency and adaptability to the channel impairments(such as being frequency selective and suffering fromnarrow-band interference and impulsive noise) The HomePlug AV2OFDMparameters correspond to a systemwith 4096 carriers

Journal of Electrical and Computer Engineering 3

101 Frame Control Encoder

AV2 Payload Data Encoder

AV2 Frame Control Encoder

Scrambler

MapperTurbo

Convolutional Encoder

Channel and ROBO

Interleaver

Insert Preamble

MIMOAFE

Power line

Turbo Product Decoder

Turbo Convolutional

Decoder

FrameControl

deinterleaver

1024 Point FFT

AGC

Time Sync

Frame Control

Demodulator

MIMOAFE

DemodulatorChannel and

ROBOdeinterleaver

Tx

Rx

Turbo Product Encoder

-input 2-Stream MIMO Decoder

101 Frame Control Decoder

DescramblerMIMO

Equalizer

Frame Control

Interleaver

Frame ControlDiversity

Copier

AV2 Frame Control Decoder

Frame Control Combine

Copies

101 Frame ControlData in

AV2 Frame ControlData in

Payload Data in

Turbo Convolutional

Decoder

Mapper IFFT(10248192)

IFFT(10248192)

Cyclic PrefixWindow and

Overlap


OverlapMIMO Stream Parser

2-Stream MIMO Transmit Encoder

Demodulator

8192 Point

FFT(1)

8192 Point

Receive Channels

MIMODemultiplexer AV2 Payload Data Decoder

PhaseShifter

AV2 Turbo Convolutional

Encoder

FFT( )

middot middot middot

101 Frame Control

AV2 Frame ControlData out

Data out

Payload Data out

AV2

Pow

er A

lloca

tion

MIM

O P

reco

ding

119873119877

119873119877

119873119877

2-Transmit channels

Figure 1 HomePlug AV2 transmitter and receiver PHY layer

in 100MHz but only carriers from 18 to 8613MHz aresupported for communication (3455 carriers)The subcarrierspacing of 24414 kHz was chosen in the HomePlug AVsystem according to the power line coherence bandwidthcharacteristic and is maintained in HomePlug AV2 forinteroperability

More significantly HomePlug AV2 incorporates MIMOcapability (see details in the next sections) to improvethroughput and coverage

A block diagram of the PHY layer is shown in Figure 1The HomePlug AV2 system is capable of supporting twonetwork operating modes AV-only mode and Hybrid mode(101 Frame Control Encoder in Figure 1) Hybrid modeis used for coexistence with HomePlug 101 stations Forthat purpose a 101 Frame Control Encoder is included forHybrid modes and an AV2 Frame Control Encoder for bothHybrid and AV-only modes The AV-only mode is used forcommunications in networks where only HomePlug AV andHomePlug AV2 stations are involved

Besides two OFDM paths are shown in order to imple-ment the MIMO capabilities with 2 transmission ports

Apart from the Hybrid or AV-only Frame Control sym-bols the payload data can be sent using adaptive bit loadingper carrier or robust modes (ROBO) with fixed QuadraturePhase Shift Keying (QPSK) constellation and several copiesof data interleaved in both time and frequency

Looking at the data path details in the block diagram(Figure 1) the following can be seen at the transmitterside the PHY layer receives its inputs from the MAC layerThree separate processing chains are shown because of thedifferent encoding for HomePlug 101 Frame Control (FC)data HomePlug AV2 FC data and HomePlug AV2 payloaddata AV2 Frame Control data is processed by the AV2 FrameControl Encoder which has a Turbo Convolutional Encoderand Frame Control Diversity Copier while the HomePlugAV2 payload data streampasses through a Scrambler a TurboConvolutional Encoder and an Interleaver The HomePlug


101 FrameControl data passes through a separateHomePlug101 Frame Control Encoder

The outputs of the FC Encoders and Payload Encoderlead into a common MIMO OFDM modulation structureconsisting of a MIMO Stream Parser that provides up totwo independent data streams to two transmit paths whichinclude two Mappers a phase shifter that applies a 90-degree phase shift to one of the two streams (to reduce thecoherent addition of the two signals) a MIMO precoderto apply transmitter Beamforming operations two InverseFast Fourier Transform (IFFT) processors preamble andCyclic Prefix insertion and symbol Window and Overlapblocks which eventually feed the AFE module with one ortwo transmit ports that couple the signal to the power linemedium

At the receiver an AFE with one two three or four (119873119877)

receive ports operates with individual Automatic Gain Con-trol (AGC) modules and one or more time-synchronizationmodules to feed separate Frame Control and payload datarecovery circuits Receivers plugged to power outlets whichare connected to the three wires Line Neutral and ProtectiveEarthmight utilize up to three differential mode Rx ports andone common mode Rx port

The Frame Control data is recovered by processing thereceived signals through a 1024-point FFT (for HomePlug101 delimiters) and multiple 8192-point FFTs and throughseparate FrameControl Decoders for theHomePlug AV2AVand HomePlug 101 modes The payload portion of the sam-pled time domain waveform which contains only HomePlugAV2 formatted symbols is processed through the multiple8192-point FFT (one for each receive port) a MIMO Equal-izer that receives119873

119877signals performs receive Beamforming

and recovers the two transmit streams two Demodulatorsa Demultiplexer to combine the two MIMO streams anda channel deinterleaver followed by a Turbo ConvolutionalDecoder and a Descrambler to recover the AV2 payload data

3 PHY Layer Improvements of HomePlug AV2

31Multiple-InputMultiple-Output (MIMO)Capabilities withBeamforming The HomePlug AV2 specification incorpo-rates Multiple-Input Multiple-Output (MIMO) capabilitieswith Beamforming which offers the benefit of improvedcoverage throughout the home particularly for hard to reachoutlets MIMO technology enables HomePlug AV2 devicesto transmit and receive on any two-wire pairs within a three-wire configuration Figure 2 shows a three-wire configurationwith Line (L) Neutral (N) and Protective Earth (PE)Whereas HomePlug AV always transmits and receives onthe Line-Neutral pair (port 1 in Figure 2) HomePlug AV2modems can transmit and receive signals on the other pairsas well Any two pairs formed by the Line Neutral orProtective Earth wires (ie L-N L-PE and N-PE) can beused at the transmitter At the receiver up to four receiveports may be used according to Figure 2The commonmode(CM) signalmdashindicated as port 4 in Figure 2mdashis the voltagedifference between the sumof the three wires and the ground

Tx

PLCmodem

1 1

2 23 3

4

PLCchannel

L

N

PE

Ground

Rx

PLCmodem

Figure 2 MIMO-PLC channel different feeding and receivingoptions

0 10 20 30 40 50 60 70 80minus 90

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

Frequency (MHz)

L-PE rarrLL-PE rarrNL-PE rarrPEL-PE rarrCM

L-N rarrLL-N rarrNL-N rarrPEL-N rarrCM

119891

|11987821|

(dB)

Figure 3 Magnitude of the transfer functions (11987821 forward scatter-

ing parameter) of all MIMO paths of a 2 times 4MIMO configuration

The numbers of used transmit ports119873119879and used receive

ports 119873119877define the MIMO configuration which is called

119873119879times 119873119877MIMO For example using L-N and L-PE to feed

and receive signals results in a 2 times 2MIMO configurationHomePlug AV2 specification supportsMIMO configurationswith up to 2 Tx ports and up to119873

119877Rx ports

Some regions and maybe homes with older electricalinstallations do not have the third wire installed in the privatebuildings In this scenario HomePlug AV2 automaticallyswitches to Single-Input Single-Output (SISO) operatingmode HomePlugAV2 incorporates also selection diversity inSISOmodeTheports used for feeding and receivingmight bedifferent from the traditional L-N feeding If for example thepath from L-PE to L-N offers better channel characteristicsthan L-N to L-N the transmitter can choose to use the L-PEport for feeding

Figure 3 shows the magnitude of several transfer func-tions of a typical MIMO-PLC channel The figure illustratesall eight possible paths of a 2 times 4MIMO configuration whereL-N and L-PE pairs are used as feeding and all four receiveports are used as receivingThe example shows that the signal


L-PEL-PE

L-N L-N

CM

N-PE

(a)

1

2

1

2

3

4

0

0

D U

VH

(b)

Figure 4 Schematic MIMO channel and decomposition into parallel and independentMIMO streams

fed into one port is visible at all receive ports Crosstalkcaused by the coupling of the wires results in the presence ofall possible MIMO paths At most frequencies the 119878

21(for-

ward scattering parameter of the network analyzer) curvesare quite independent As less correlation the 119878

21curves

show as higher is the gain by MIMO For some frequenciesfor example in the region of the fading degradation around16MHz the shapes of the transfer functions are similar dueto the same underlying topology of the different MIMOpaths Usually the wires are located in parallel within thewalls facing a similar multipath propagation This results ina higher spatial correlation of the MIMO-PLC channel thancompared to radio MIMO channels

More information about the MIMO-PLC channel char-acteristics and channel modeling may be found in [6ndash18]

The channels presented in Figure 3 were recorded with adelta coupler at the transmitter (L-PE L-N) and a star couplerat the receiver (L N PE CM) This coupler combinationallows 2 times 4MIMO [19]

The MIMO-PLC channel is described by a 119873119877

times 119873119879

channel matrix for each OFDM subcarrier 119888

H (119888) =[[

[

ℎ11

(119888) sdot sdot sdot ℎ1119873119879

(119888)

ℎ1198731198771

(119888) sdot sdot sdot ℎ119873119877119873119879

(119888)

]]

]

(1)

with 119888 belonging to the set of used subcarriers (dependingeg on the frequency band and tone mask)

Figure 4(a) shows the schematic MIMO channel for a2 times 4MIMO configuration with the overall 8MIMO pathsHomePlug AV2 supports 1 or 2 streams (see Section 311) AsHomePlug AV2 supports MIMO configurations with up to2 Tx ports and up to 119873

119877Rx ports the maximum number of

supported streams in AV2 is 2The number of the underlyingMIMO streams depends on the rank of the channel matrixIf the channel matrix has full rank the number of MIMOstreams is = min(119873

119879 119873119877)The underlyingMIMO streams are

obtained by a Singular Value Decomposition (SVD) of thechannel matrix [20]

H (119888) = U (119888)D (119888)V(119888)119867 (2)

where V and U are unitary matrices that is Vminus1 = V119867and Uminus1 = U119867 (with 119867 the Hermitian operator) and D

0

0

10 20 30 40 50 60 70 80minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

Frequency (MHz)

Feeding L-N and L-PE receiving L N PE and CM

Stream 1Stream 2SISO L-N rarrP

119891

|11987821|

(dB)

Figure 5 Attenuation of the decomposed PLC-MIMO channel ofFigure 3

is a diagonal matrix containing the singular values of HFigure 4(b) illustrates this decomposition

Figure 5 shows the decomposition of the two streams oftheMIMO-PLC channel shown in Figure 3 As a comparisonthe attenuation of the SISO channel is also depicted

The decomposition into parallel and independent streamsby means of the SVD illustrates the MIMO gain instead ofhaving one spatial stream in SISO two independent spatialstreams are available in a 2 times 119873

119877MIMO configuration with

119873119877ge 2 doubling in average theMIMO capacity [9 12 13 21]

This fact is also verified by means of Figure 5 the first spatialstream shows less attenuation compared to the SISO channelthe second stream is slightly higher attenuated compared toSISO Hence in this example the MIMO link would result inmore than twice the capacity of the SISO link

311MIMOStreamParser Depending onhowmany streamsare used in the transmission the payload bits have to be splitinto different spatial streams This task is performed by theMIMO Stream Parser (MSP) The MSP splits the incoming


bits into one or two streams based on the MIMO modeof operation and the Tone Map information (see Figure 1)To transmit a single-stream payload with Spot-Beamforming(see Section 313) or for SISO transmissions the MSP sendsall the data at its input to the first Mapper In this casethe MSP operates as if it had only one output and it wasconnected to the first mapper in Figure 1 To transmit a two-stream payload with Eigen-Beamforming (see Section 313)the MSP allocates the bits to the two streams

312 Precoding Precoded Spatial Multiplexing or Beam-forming was chosen as the MIMO scheme as it offersthe best performance by adapting the transmission in anoptimum way to the underlying Eigen modes of the MIMO-PLC channel The best performance is achieved for variouschannel conditions On the one hand the full spatial diversitygain is achieved in highly attenuated and correlated channelswhen each symbol is transmitted via each available MIMOpath On the other hand a maximum bit rate gain is achievedfor channels with low attenuation when all available spatialstreams are utilized Beamforming also offers flexibility withrespect to the receiver configuration Only one spatial streammay be activated by the transmitter when only one receiveport is available that is if the outlet is not equipped with the3rdwire or if a simplified receiver implementation is used thatsupports only one spatial stream Since Beamforming aimsto maximize one MIMO stream the performance loss of notutilizing the second stream is relatively small compared tothe Spatial Multiplexing schemes without precoding This isespecially true for highly attenuated and correlated channelswhere the second MIMO stream carries only a small amountof information These channels are most critical for PLCand adequate MIMO schemes are important A comparisonand analysis of different MIMO schemes may be found in[14 21 22]

Beamforming requires knowledge about the channel stateinformation at the transmitter to apply the optimum precod-ing Usually only the receiver has channel state informationfor example by channel estimation Thus the informationabout the precoding has to be fed back from the receiver tothe transmitter The HomePlug AV2 specification supportsadaptive modulation [23 24] The application of adaptivemodulation also requires feedback about the constellationof each subcarrier (Tone Map) that is the feedback path isrequired anyway The information about the Tone Maps andthe precoding are updated simultaneously upon a change inthe PLC channel (realized by a channel estimation indicationmessage) The information about the precoding is quantizedvery efficiently and the amount required for the precodinginformation is in the same order of magnitude as theinformation about the Tone Maps Thus the overhead interms of management messages and requiredmemory can bekept low

The optimum linear precoding matrix F for a precodedSpatial Multiplexing system can be factored into the twomatrices V and P [25]

F = VP (3)

2-stream MIMO Encoder

Mapper

Mapper

MIMO Power

Allocation Phase Shifter

IFFTMIMO Pre-Coding

(10248192)

IFFT(10248192)

VCompute V

index index

= V2times 21199041

1199042

1199091

1199092

1199041

1199042

1199091

1199092

120595 120579

Figure 6 Precoding at the transmitter

Note that the subcarrier index is omitted in (3) and in thefollowing section to simplify the notation and to allow betterlegibility However it has to be kept inmind that the followingvector and matrix operations are applied to each subcarrierseparately if not stated otherwise

P is a diagonal matrix that describes the power allocationof the total transmit power to each of the transmit streamsPower allocation is considered in more detail in Section 314V is the right hand unitary matrix of the SVD of the channelmatrix (see (2)) Precoding by the unitary matrix V is oftenreferred to as unitary precoding or Eigen-Beamforming

Figure 6 shows the basicMIMOblocks of the transmitterThe Mappers of the two streams follow the MIMO streamparser (see Figure 1) The two symbols of the two streamsare then weighted by the power allocation coefficients andmultiplied by thematrixV (the computation of V is explainedin Section 313 in more detail) Finally each stream is OFDMmodulated separately

313 Beamforming and Quantization of the BeamformingMatrix The precoding matrix V is derived by means of theSVD (see (2)) from the channel matrixH

There are two possible modes of operation If only onespatial stream is utilized single-stream Beamforming (orSpot-Beamforming) is applied In this case the precodingis described by the first column vector of V that is theprecoding simplifies to a column vector multiplication Notethat despite the fact that only one spatial stream is used bothtransmit ports are active as the precoding vector splits thesignal to two transmit ports If both spatial streams are usedtwo-stream Beamforming (or Eigen-Beamforming) is usedand the full precoding matrix V is applied in the MIMOprecoding block in Figure 6

Since the information about the precoding matrix has tobe fed back from the receiver to the transmitter an adequatequantization is required To achieve this goal the specialproperties of V are utilized

The unitary property of V consequences that the columnsv119894(119894 = 1 2) of V are orthonormal that is the column vectors

are orthogonal and the normof each columnvector is equal to1 [26]There ismore than one unique solution to the SVD thecolumn vectors of V are phase invariant that is multiplyingeach column vector of V by an arbitrary phase rotation resultsin another valid precoding matrix


5 10 15 20 25 300

5

10

15

20

25

30

35

40

45

50SN

R (d

B)

Spatial MultiplexingBeamforming

Frequency (MHz)119891

(a)

5 10 15 20 25 300

5

10

15

20

25

30

35

40

45

50

SNR

(dB)



(b)

88

88

888

88

10

1010

1010

10

1010

12 12

1212

12

1414

14

14

16

16

16

181818

2020

2222 24262830320

1

2

3

4

10

15

20

25

30

0 05 151

11 dB

minus 4

minus 3

minus 2

minus 1

Optimum precoding 35 dBNo precoding 11 dB

SNR1 ( θH)

(ψ θH) at 13 MHzSNR1

120595

120595

120579

(c)

8 8

8 88

888

10

10

1010

1010

10

1010

1212

1212 12

1212

1212 12

1414

14 14

1414

14 14

16

16 16

16

16 16

1818

18

181818

20

20

20

20

2222

2222

24

24

26

26

28

28

30

30

32

32

0

1

2

3

4

10

15

20

25

30

0 05 151

8 dB

minus 4

minus 3

minus 2

minus 1


θ

SNR2 ( θH)


120595

120595

(d)

Figure 7 Influence of precoding on the SNR SNR of the first (a) and second (b) streams with and without precoding transmit power tonoise power of 120588 = 65 dB 40 dB average channel attenuation SNR depending on the precoding matrix at 13 MHz of the first (c) and second(d) streams

These properties allow to represent the complex 2 times 2

matrix V by only the two angles 120579 and 120595

V = [v1 v2] = [

11990711

11990712

11990721

11990722

] = [cos120595 sin120595

minus119890119895120579 sin120595 119890

119895120579 cos120595] (4)

where the range of 120579 and 120595 to represent all possible Beam-forming matrices is 0 le 120595 le 1205872 and minus120587 le 120579 le 120587

According to the phase-invariance property the firstentry of each column (119907

11 11990712) may be set to be real without

loss of generality as defined in (4) It is easy to prove thatthe properties of the unitary precoding matrix are fulfilled

The norm of the column vectors is one |11990711|2+ |11990721|2

=

|11990712|2+ |11990722|2= sin2(120595) + cos2(120595) = 1 Also the two columns

are orthogonal

v1198671v2= sin (120595) cos (120595) minus sin (120595) cos (120595) 119890

minus119895120579119890119895120579

= 0 (5)

In both modes Spot-Beamforming and Eigen-Beamforming the Beamforming vector or Beamformingmatrix respectively is described by both angles 120579 and 120595Thus the signaling of 120579 and 120595 is the same in both modes


If the MIMO Equalizer is based on zero-forcing (ZF)detection the detection matrix

W = H119901 = (H119867H)minus1

H119867 (6)

is the pseudo inverse HP of the channel matrix H In caseof Eigen-Beamforming with the precoding matrix V H canbe replaced by the equivalent channel HV in (6) and thedetection matrix can be expressed by

W = V119867H119901 = Dminus1U119867 (7)

The SNR of the MIMO streams after detection is calcu-lated as

SNR1= 120588

1

1003817100381710038171003817w11003817100381710038171003817

2 SNR

2= 120588

1

1003817100381710038171003817w21003817100381710038171003817

2 (8)

with 120588 being the ratio of transmit power to noise power and119908119894 the norm of the ith row of the detection matrixWFigure 7(a) shows the SNR of the first stream of aMIMO-

PLC channel The median attenuation of this link is 40 dBThe ratio of the transmit power to noise power is 120588 = 65 dBThe blue line represents the SNR of Spatial Multiplexingwithout precoding and the green line represents the Eigen-Beamforming The SNR of the 2nd stream is displayed inFigure 7(b)

The two markers X in Figure 7(a) mark a frequency(13MHz) where good Beamforming conditions are foundDifferent precoding matrices influence the SNR of the twoMIMO streams according to (6) and (8)

Figures 7(c) and 7(d) show the level of the gain or signalelimination due toBeamforming for the frequencymarked byX in Figures 7(a) and 7(b)The color lines in Figures 7(c) and7(d) indicate the SNR Depending on the precoding matrixthe SNR varies between 6 dB and 35 dB No Beamforming(120595 = 0 and 120579 = 0) would result in a SNR of 11 dB Asseen in Figure 7(c) there is one SNR maximum in the areaspanned by 120595 and 120579 Due to both streams being orthogonalone shows an SNR minimum at the location where the otherone has its maximum The SNR plot in Figures 7(c) and 7(d)is 2120587 periodic in 120579 where the black horizontal lines indicate120579 = plusmn120587

The Beamforming matrix is quantized efficiently toreduce the amount of feedback required to signal V Thisquantization is chosen such that the loss of the SNR afterdetection (refer also to (6) and (8)) is within 02 dB comparedto optimum Beamforming without quantization

314 Power Allocation MIMO power allocation is appliedto two-stream MIMO transmissions The power allocationadjusts the power of a carrier on one stream relative tothe other stream For SISO transmissions and MIMO Spot-Beamforming transmissions MIMO power allocation canbe bypassed since there is only one transmit stream In thiscase the only available option is to allocate all the power tothe single stream The power allocation module is locatedbetween the Mapper and the precoding block (see Figure 1)and performs on the two MIMO streams before Eigen-Beamforming The power allocation in AV2 is designed in a

way not to feed back additional information from the receiverto the transmitter The power allocation evaluates the ToneMaps of the two streams to set the power allocation coeffi-cients of the two streams It was shown that the performanceis very close to the optimumpower allocation (mercurywaterfilling [27]) Power allocation improves especially highlyattenuated channels at the high coverage point

315 Precoding Grouping HomePlug AV2 devices supportan expanded frequency spectrum (up to 8613MHz seeSection 32) and one additional stream (utilizing MIMO)compared to the 30MHz for HomePlug AV devices ThusHomePlug AV2 devices need to store two ToneMaps (one foreach stream) and one precoding matrix (PCM) per carrierThis significantly increases the memory requirements foran AV2 modem In order to save memory HomePlug AV2devices transmit and store the PCM only on a subset ofcarriers called precoding pilot carriers At the transmitterthe PCMs for the carriers between two adjacent precodingpilot carriers are obtained via interpolation The spacingbetween the precoding pilot carriers is selected out of aset of predefined values and may be adjusted dependingon the memory capabilities or channel conditions Themore memory is embedded in the modems the finer thegranularity is The performance loss of precoding groupingcompared to the quantization of each subcarrier separatelyis marginal due to the high correlation of the precodingmatrices of neighbored subcarriers An investigation aboutdifferent precoding grouping algorithms for MIMO-PLCmay be found in [14]

32 Extended Frequency Band up to 86MHz During thespecification development the AV TWG realized a mea-surement campaign where power line channel and noisemeasurements were performed in 30 homes located indifferent countries from Europe to USA Such variabilitywas a key ingredient to obtain insight into the power line atfrequencies above those used inHomePlugAV (18ndash30MHz)In particular in every home all the possible links among atleast 5 different nodes were measured

Examples of recorded channel attenuation and noise PSDare reported in Figures 8 and 9 respectively

Based upon the results of themeasurement campaign thepresent EMC regulations coverage and complexity targetsthe final outcome of the analysis was the selection of the 30ndash86 MHz band for the following reasons

(i) The FM band region 875ndash108MHz shall be avoidedIn fact this frequency region presents higher attenu-ation and higher noise compared to the 30ndash86MHzband (see also Figures 8 and 9) Since probablylower transmit level requirements will be needed inorder to not interfere with the FM radio service verylow operating SNRs are obtained in this band withnegligible coverage increase

(ii) The 30ndash86MHz frequency band appears to offer athroughput increase especially at the low to midcoverage percentages the reason is that while the


2 4 6 8 10Frequency (Hz)

Atte

nuat

ion

(dB)

times 107

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

Figure 8 HomePlug AV2 measurement campaign Example ofchannel measurement

PSD

(dBm

Hz)

2 4 6 8 10Frequency (Hz) times 107

minus 160

minus 150

minus 140

minus 130

minus 120

minus 110

minus 100

Figure 9 HomePlug AV2 measurement campaign Example ofnoise measurement

attenuation is greater compared to the 18ndash30MHzband noise is lower A concern derives from the factthat EMC requirements for the 30ndash86MHz frequencyband are generally tighter than in the 18ndash30MHzband However this observation could be mitigatedin view of the fact that for instance the upcomingstandard FprEN50561-1 appears to bemore restrictivein the 18ndash30MHz frequency band

(iii) Within the HomePlug AV2 specification it has beenpossible to provide flexibility in choosing the stopfrequency in the 30ndash86 MHz interval In particularan AV2 device implementing a frequency band 18-119883MHz band (with 30 lt 119883 lt 86) will beinteroperablewith a device implementing a frequencyband 18-119884MHz (with 30 lt 119884 lt 86119883 = 119884)

(iv) The 30ndash86 MHz frequency band extension allowsdevices to be fully interoperable with the IEEE 1901devices that use the 18ndash50MHz frequency bandIn fact HomePlug AV2 devices that implement afrequency band extension shall support at least theIEEE 1901 bandwidth

0 10 20 30 40 50 60 70 80 90 100

0

Frequency (kHz)

Mag

nitu

de (d

B)

RectangularBarlettBlackmann

HammingRaised CosineKaiser

minus 100

minus 90

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

55 dB58 dB

27 dB42 dB 32 dB

13 dB

Figure 10 OFDM side lobes of a single carrier Comparison ofvarious window functions

33 Efficient Notching HomePlug AV2 increases throughputby allowing devices to minimize the overhead incurreddue to EMC notching requirements While in HomePlugAV the mechanism (ldquowindowed OFDMrdquo) for creating thePSD notches is fixed and relatively conservative HomePlugAV2 devices may gain up to 20 in efficiency if theyimplement additional techniques to accommodate sharperPSD notches The 20 includes the gain of guard carrierswhich were excluded by HomePlug AV modems and thereduced Transition Interval in time domain Such devicesgain additional carriers at the band edges and may utilizeshorter cyclic extensions which reduces the duration of theOFDM symbols

331 Influence of Windowing on Spectrum and Notch ShapeThe FFT process uses a rectangular window to cut dataout of a continuous stream to convert them from time tofrequency domain The FFT of a rectangular function in thetime domain is a sin(119909)119909 function in the frequency domainThe sin(119909)119909 becomes 0 at integer multiples of 120587 Some partsof the signal remain in-between the zeros which results inthe unwanted side lobes of an FFT OFDM system Figure 10shows a sin(119909)119909 function as green curve The frequencyaxis is shown horizontally The level in a logarithmic view ispresented on the vertical axis

The process of multiplying a window with an OFDMsymbol (see Figure 11) in the time domain aims to suppressthe sharp corners at the beginning and the end of the OFDMsymbol in order to get smooth transitions This affects theshape and distances of the side lobes in the frequency domain[28]There are numerous types of window functions availablefor implementation such as Hamming Barlett (triangular)Kaiser Blackman Raised Cosine (Hann) and so forth Acomparison of various window waveforms with the achievedside lobe attenuation is shown in Figure 10 which also serves


Copy and window

Copy and window

Raised Cosine guard interval


Flat guard

interval

FFT section

Figure 11 OFDM symbol with GI and window

= 0 = RI

RIRI GI

TI2

TI2

TI2

TI2

I2

RI2

OFDM symbol

Figure 12 ConsecutiveOFDMsymbols guard interval (GI) roll-offinterval (RI) and windowing

115 12 125 13 135 14

0

5

10

Frequency (MHz)

Pow

er (d

B)

10 carriers notch

543

2Singlecarriernotch

minus 30

minus 25

minus 20

minus 15

minus 10

minus 5

= 0= 001= 003125

= 00625= 0121

Figure 13 OFDM spectra with different notch widths and depthsachieved with different roll-off factors

to illustrate the disadvantage of windowingThe side lobes aresuppressed but the main lobe stays wider The first time thespectrum reaches zero the distance for all windows is at leasttwice the frequency of the rectangular window used by thepure FFT Windowing is considered to be state of the art insignal processing [29]

The process of how a window is applied is shown inFigure 11 The original OFDM symbol or the output of theIFFT at the transmitter is marked with ldquoFFT sectionrdquo Asdescribed above the guard interval is copied from the tailsamples to the beginning of the symbol In order to createa window the symbol has to be expanded further at the

beginning and at the end by copying the bits as done forthe Guard Interval (GI) This expansion is multiplied withthe smoothly descending window The more smoothly thesignal approaches zero in the time domain the lower the sidelobes in the frequency domain Of course this expansion of asymbol is a waste of communication resources as it does notcarry useful information and has to be cut by the receiver

The two descending slopes in the time domain couldoverlap to save communication resources at consecutiveOFDM symbols as shown in Figure 12The new symbol time119879119904ismeasured between themiddles of the roll-offs before and

after the symbol The overlap region is the roll-off interval(RI) (see in Figure 12) which is related to the OFDM symbolduration 119879

119904via the parameter 120573

RI = 120573119879s (9)

and the total symbol length 119879119864

119879119864= (1 + 120573) sdot 119879s (10)

The HomePlug AV specification allows the usage of sev-eral Guard intervals [30 31] If the shortest guard intervalis selected HomePlug AV uses a 120573 of RI(119879 + GI) =

496 120583119904(4096 120583119904 + 556 120583119904) = 01066With HomePlug AV2 the Transition Interval TI is intro-

ducedThe shape of the windowing is transmitter implemen-tation dependent it does not affect interoperabilityThe pulseshaping window and Guard interval might be reduced evento zero to minimize overhead in time domain and to notchefficiently In order to guarantee backward compatibility withprevious HomePlug versions the definition and timings ofthe parameter RI as shown in Figure 12 have to stay stableIn contrast to RI the new parameter TI might be reduced tozero

There is a balance between this intervals and obtaining abetter side lobe attenuation

Figure 13 shows the notch of anyOFDM system spectrumwhich could be obtained by varying the roll-off factors(the 120573 values) of the Raised Cosine window Increasing theroll-off factor directly increases the amount of attenuationachieved inside the notches However this has the drawbackof increased symbol length

To create notches in the OFDM spectrum a modelis implemented using QAM modulation and notches ofomitting a various number of carriers 1 2 3 4 5 and 10 Amax-hold function is implemented in order to create these


figures The 10 carrier notch shows the spectral benefit ofwindowing The influence of windowing is hardly visible upto the point of the 5-carrier notch At the 5-carrier notchthe difference between no window and the highest simulated120573 is around 5 dB The trade-off for this 120573 is a 27 longersymbol time At the 10-carrier notch the center frequencyis suppressed by more than 15 dB without windowing butthe adjacent side slopes of the used corner carriers are onlyimproved by 5 dB

The additional overhead in the time domain is extremelylarge compared to the improved notch depth Windowingwith a small roll-off factor is sufficient in order to suppressthe side lobes outside the used spectrum but it is notrecommended to increase the depth of a single carrier notch

In the case of the HomePlug AV specification using a 120573

of 01066 some guard carriers on the left and right side ofa protected frequency range have to be omitted to guaranteethe depth of the notch The North American Carrier Maskrequests 10 notches in-between 17MHz and 30MHz Thefirst carriers as well the last carriers of this spectrum arenotchedThese twonotches have only one slope to the carriersallocated for communications All other notches have twoslopes resulting in 18 notch slopes in totalThe spectrum losesalmost 6of communication resources in frequency domainAdditionally the 120573 causes almost 13 of wasted resourcesin time domain Assuming an ideal implementation withmaximal sharpness in time as well as frequency domain itwould be possible to regain these communication resourceswhen applying the North American Carrier Mask If thefrequency spectrum becomes more fragmented because ofadditional notches like requested by the newly upcomingEuropean regulations [32] these losses become even moreobvious

332 Digital Adaptive Band Stop Filters Improve the NotchrsquosDepth and Slopes Of course an ideal implementation asdescribed above is not possible but digital band stop filtersincrease the sharpness of the notches as well the imple-mentation efforts in hardware Shrinking the semiconductormanufacturing process to smaller structures allowing tointegrate additional functions on the same die size shifts thebalance towards hardware implementation efforts

HomePlug AV2 specification gives maximum freedom tothe chip implementer Filter algorithm order and structureare implementation dependent An example is documentedin [19] As higher the filtering efforts as better is the sharpnessof the notch slopes as shorter might be GI as higher theresources available for communication A reduction of theGuard Interval down to zero (see Section 351) is possibleat short PLC channels without multipath reflections orintersymbol interference

34 HomePlug AV2 Power Optimization Techniques TheHomePlug AV2 standard introduces two novel techniquesthat can be used to optimize the use of transmit power Thefirst one named ldquotransmit power back-offrdquo is a technique thatreduces the transmitted power spectral density for a selectedset of carriers when this can be done without adversely

affecting performance Conversely the second techniquecalled ldquoEMC Friendly Power Boostrdquo is a technique that allowsthe transmitter to increase the power on some carriers withthe knowledge that this can be done without exceedingregulatory limits

341 Power Back-Off In power line communications thetransmit power limit is typically defined as a power spectraldensity (PSD) mask applicable over the range of frequenciesused in the standard And since power line modems aredirectly connected to the electrical wiring they are tradi-tionally designed to transmit with the maximum allowedtransmit PSD on each frequency (ie they do not needto be sensitive to a limited battery supply) In many casesmaximizing transmit power leads to the best performancehowever certain definitions of PSD masks combined withcertain channel conditions can produce cases where modemscan benefit from transmitting at less than the maximumallowed power level

We illustrate the benefits of transmit power control usingthe North American regulatory limits as an example FCCregulations that are applicable to power line devices inNorth America are commonly interpreted to allow a transmitPSD of minus50 dBmHz from 18 to 30MHz and minus80 dBmHzfrom 30MHz up to 86MHz This 30 dB drop in the PSD(at 30MHz) causes the signal from the higher frequencycarriers (above 30MHz) to have much smaller amplitudethan the signal for the low band carriers (up to 30MHz)Consequently when the overall signal is represented in aquantized digital domain the high band signal has lowerresolution than the signal in the lower band andwill thereforealso have a limited SNRThiswill be evident at the transmitterwhere the 30 dB drop will result in a reduction of 5 bits ofresolution for the high band signal If the transmit poweris backed off in the low band so that the PSD drop isreduced then the high band signal will be represented withan increased number of bits of resolution and enjoy increasedSNRs out of the transmitter

Another limiting factor is the limited dynamic rangeof the analog to digital converter (ADC) We illustrate itsimpact using once again the example of the North AmericanPSD limits For the sake of simplicity we assume a flatpower line channel and flat noise spectrum in Figure 14 Forconvenience the power line channel (cyan curves labeledRx signal the transmitted signal after channel attenuation)and noise (green curves labeled Rx noise) contributionsto the received signal are shown separately Moreover thedifferent signals are shown before (dashed line curves) andafter (continuous line curves) the analog amplifier On the leftof Figure 14 the scenario without power back-off is shownthe transmitted signal is 30 dB greater in the 18ndash30MHzband compared to the 30ndash86MHz bandThe analog amplifierbrings the received signal to a level A tailored to optimizethe ADC conversion Since the dominating noise is the ADCnoise (black curve) after the ADC converter SNRs of 35 dBand 5 dB are found below and above 30MHz respectivelyOn the right of Figure 14 the scenario with power back-off is shown the transmitted signal is reduced by 10 dB


Frequency (Hz)

PSD

(dBm

Hz)

Rx signal (after analog amplifier)Rx noise (after analog amplifier)Rx signal (before analog amplifier)Rx noise (before analog amplifier)ADC noise

2 4 6 8 100times 107

A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 5 dB

SNR

=35

dB

(a)


Frequency (Hz)2 4 6 8 100

times 107PS

D (d

BmH

z)A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 10 dBSNR

=30

dB

(b)

Figure 14 Benefits of power back-off (a) No power back-off (b) 10 dB power back-off

in the 18ndash30MHz frequency band so that it is only 20 dBgreater compared to the 18ndash86MHz band Again the analogamplifier brings the received signal to the A level Howeverin this case the dominating noise is no longer the ADC noiseand the obtained SNRs are 30 dB and 10 dB in the 18ndash30MHzand 30ndash86MHz respectively

In this example the power back-off technique results ina 5 dB SNR reduction for the carriers in the lower frequencyband and a 5 dB SNR increase for the carriers in the upperfrequency band Given the larger bandwidth of the upperfrequency band there will be an overall throughput gain dueto transmit power back-off

Transmit power back-off is also an effective interferencemitigation technique For instance in Europe the ability ofa PLC transmitter to reduce the transmit power dependingon the attenuation link is a possible requirement consideredin [32] though the procedure described in [32] does notconsider Quality of Service (QoS) requirements of PLCmodems

342 EMC Friendly Power Boost Using 11987811

Parameter TheEMC Friendly Power Boost is a mechanism introduced inthe HomePlug AV2 specification to optimize the transmitpower by monitoring the input port reflection coefficient atthe transmitting modem This coefficient is known as the

11987811

parameter PSD limits as proposed in the HomePlugAV2 specification are based on representative statistics ofthe impedance match at the interface between the deviceport and the power line network In practice the inputimpedance of the power line network is frequency selectiveand varies for different network configurations This leadsto part of the transmit power being dissipated within thetransmitter The input port reflection coefficient or inputreturn loss is characterized by the 119878-parameter 119878

11 and

the part of transmit power dissipated at the transmitter isgiven by the amount 20 sdot log 10(|119878

11|) in dB In situations

where the impedance mismatch is large (and thus the 11987811

parameter is large) only a small part of the input poweris effectively transferred to the power lines In those casesthe Electromagnetic Interference (EMI) induced by the PLCmodem is reduced and can be much lower than the valuesrecommended by EMC regulation limits

In order to compensate for the frequency selectiveimpedance mismatch at the interface between the deviceport and the power line network HomePlug AV2 modemsadapt their transmission mask upon measurement of the 119878

11

parameter at the transmitter The transmitted signal power isincreased by an Impedance Mismatch Compensation (IMC)factor leading a more effective power transmission to thepower line medium While increasing the Tx power leads to


an increase of the radiated EMI the design of the IMC factorensures that the resulting EMI continuously falls below thetargeted EMC regulation limits

A statistical analysis was conducted on the practicalvalues of the 119878

11parameter and the effectiveness of the

EMC Friendly Power Boost technique based on a seriesof measurements performed by the ETSI Specialist TaskForce 410 [6ndash10 33] 119878

11parameter and EMI measurements

were taken over the 1MHzndash100MHz range in 6 countriesGermany Switzerland Belgium UK France and Spain Themodem used for measurements is described in [6ndash8]

The 11987811measurements considered in this study consist of

3 differential feeding possibilities (L-N N-PE and PE-L) and1 common mode feeding (CM) For the EMI measurementswe consider the measurements taken with different feedingpossibilities that is differential feeding with the other differ-ential ports being unterminated or terminated with 50Ohmand CM feeding

The measurement set used in this analysis consists of 478frequency sweeps that can be categorized as follows

(i) 6 different locations in Germany and 3 differentlocations in France

(ii) 264measurements outdoor at 10m 43measurementsoutdoor at 3m and 171 measurements indoors

Statistical analysis of this experimental data alloweddesigning the practical implementation of the EMC FriendlyPower Boost technique In the following we define theImpedance Mismatch Compensation (IMC) factor as (in dB)

IMC (119896) = min(max(10 sdot log10

(1

1 minus100381610038161003816100381611987811 (119896)

1003816100381610038161003816

2)

minus119872(119896) 0) IMCmax)

(11)

where 11987811(119896) is the carrier dependent estimate of the 119878

11

parameter 119872 is a margin accounting for possible estimateuncertainties in the measurement of parameter 119878

11 and

IMCmax is the maximum allowed value of the IMC factor indB

Figures 15 and 16 represent the statistical CDF of the11987811

parameter as well as the corresponding IMC0factor

computed with a marginM of 0 dBThese statistics are basedon the experimental data collected during the ETSI STF 410measurement campaign

On Figure 15 one can read that the 11987811parameter is larger

than minus10 dB for 80 of the cases This means that for 80of the records more than 10 of the energy is reflected backtowards the transmitter

More interestingly Figure 16 gives an idea of the potentialpower increase offered by the EMC Friendly Power Boosttechnique

(i) For 40 of the records the Tx power could beincreased by more than 2 dB to compensate for theimpedance mismatch

0

02

04

06

08

1

minus 70 minus 60 minus 50 minus 40 minus 30 minus 20 minus 10 011 (dB)

CDF

of11119878

Figure 15 CDF of 11987811parameter

0 2 4 6 8 10 12 14 160

02

04

06

08

1

IMC (dB)

CDF

of IM

C

Figure 16 CDF of IMC parameter

(ii) For 10 of the records the Tx power could beincreased by more than 4 dB to compensate for theimpedance mismatch

We then focused on the effect of the EMC Friendly PowerBoost technique on the radiated EMI statistics The recordedvalues allowed the computation of two statistics

(i) the statistical CDF of the recorded EMI in terms ofE-field for all frequencies and feeding possibilitieswithout applying any power boost

(ii) the statistical CDF of the recorded EMI in terms of E-field for all frequencies and feeding possibilities whenapplying the EMC Friendly Power Boost

Figure 17 presents for each percentile of the CDF thedifference in dB between the E-Field CDFs for the twomethods of transmission

Different observations can bemade from this figure Firstthe application of the EMC Friendly Power Boost leads to anincrease of the radiated field CDF comprised between 0 and6 dB Note that the extreme value of 6 dB arises for one ofthe lowest values of radiated field and hence is not relevantSecondly in general the application of the EMC FriendlyPower Boost increases the radiated power CDF by about 2 dBMore importantly the increase of the radiated power CDFis lower than 2 dB for the 25 most radiating cases Thispractically means that in the worst case scenarios where the


1 15 2 25 3 35 4 45 50

01

02

03

04

05

06

07

08

09

1

Perc

entil

e

Low EMIvalues

High EMIvalues

Difference between CDF (119864-field + IMC0) and CDF (119864-field) (dB)

Figure 17 Difference in dB between the CDFs of the radiated EMIbefore and after applying the EMC Friendly Power Boost

modems produce the largest EMI the application of the IMCfactor does not increase the EMI by more than 2 dB Thisvalue can be compared with the CDF of the IMC factor givenin Figure 16 Although the IMC factor is larger than 2 dB in40 of the cases and larger than 4 dB in 10 of the casesthe application of the EMC Friendly Power Boost techniquesdoes not increase the radiated power CDF extreme valuesby more than 2 dB Of course even an increase of the EMIby 2 dB is not acceptable Therefore a margin M of 2 dB isapplied when increasing the Tx power using the IMC factor

Based on this study we conclude that the applicationof the EMC Friendly Power Boost technique provides asignificant gain in terms of transmit power increase for a largenumber of configurations where the impedance mismatchcauses the dissipation of the signal at the transmitter Inaddition the statistical analysis shows that this techniquewill not lead to an increase of the undesirable radiatedinterference in particular in the worst EMI scenarios as longas a marginM of 2 dB is used in the computation of the IMCfactor as specified in (11) Finally a recommended limit forthe maximum allowed value of the IMC factor is IMCmax =

6 dB

35 Additional PHY Improvements In addition to theMIMOtechnology the frequency band extension the EfficientNotching and power optimization techniques such as thepower back-off and the EMC friendly power boost otherelements of the PHY layer were modified as presented in theparagraphs below

351 New Time Domain Parameters In the HomePlug AV2specification a number of time domain parameters wererefined As the sampling frequency has increased from75MHz to 200MHz the number of time samples for a givensymbol duration is increased by a factor 83 the IFFT intervalis 8192 samples in length and the number of samples in theHomePlug AV Guard Interval has increased accordingly Inaddition new features have been added

(i) The Transition Interval defines the part of the Roll-off Interval dedicated to the transitionwindow allow-ing more flexibility in the choice of the window(see Section 33)

(ii) A new Guard Interval has been defined for theHomePlug AV2 Short Delimiter (see Section 421)

(iii) The payload symbol Guard Interval has been madevariable and can be as short as 0 120583s It can also beincreased up to 1956120583s This allows adaptation to awide range of channel conditions and removes theoverhead of the Guard Interval for channels thathave either very low multipath dispersion or that arecompletely limited by the receive noise and not by ISI

352 Additional Constellations In HomePlug AV the max-imum constellation size is 1024-QAM corresponding to 10coded bits per carrier HomePlug AV2 also provides supportfor 4096-QAM which corresponds to 12 bits per carrier Thehigher constellation size increases the peak PHY rates by20 Practically the increased throughput will be availablemostly on average to very good channels but even someof thepoorer channels sometimes have frequency bands in whichhigh SNRs can be achieved and the increased constellationsize can be used

353 Forward Error Correction (FEC) Coding HomePlugAV2 uses the same duobinary Turbo Code as HomePlug AVIn addition to the code rates of 12 and 1621 HomePlugAV2 also provides support for a 1618 code rate This allowsmore granularity in the compromise between robustnessand throughput degradation For this new code rate a newpuncturing structure is defined as well as a new channelinterleaver In addition a new Physical Block size of 32octets is defined which includes specification of a newtermination matrix for the FEC as well as a new interleaverseed table The 32-byte octet PBs are used in the PHY levelacknowledgements and allow for the acknowledgement ofmuch larger packet sizes that are supportedwith the increasedPHY rates possible in HomePlug AV2

354 Line Cycle Synchronization The HomePlug AV2 spec-ification describes also the device operation in scenarioswhere there is no alternating current (AC) line cycle (ega direct current (DC) power line) or when the AC linecycle is different from 50Hz or 60Hz In this case theCentral Coordinator is preconfigured to select a BeaconPeriod matching either 50Hz (ie Beacon Period is 40msec)or 60Hz (ie Beacon Period is 3333msec) One key use casewhere this feature is useful is the transfer of data towards amultimedia equipped electrical vehicle during the electricalcharging phase (using DC power)

4 MAC Layer Improvements ofHomePlug AV2

41 Power Save Modes HomePlug AV2 stations improvetheir energy efficiency in standbymode through the adoption


of the specific Power Save Mode already defined in theHomePlug Green PHY [4] specification In Power Savemode stations reduce their average power consumption byperiodically transitioning between Awake and Sleep statesStations in the Awake state can transmit and receive packetsover the power line In contrast stations in Sleep statetemporarily suspend transmission and reception of packetsover the power line

We introduce some basic terms useful to describe thePower Save Mode

(i) AwakeWindow period of time during which the sta-tion is capable of transmitting and receiving framesThe Awake Window has a range from a few millisec-onds to several Beacon Periods (a Beacon Period istwo times the AC line cycle 40ms for a 50Hz AC lineand 333ms for a 60Hz AC)

(ii) Sleep Window period of time during which thestation is not capable of transmitting or receivingframes

(iii) Power Save Period (PSP) interval from the beginningof one Awake Window to the beginning of the nextAwakeWindow Power Save Period is restricted to 2119896multiples of Beacon Periods (ie 1 Beacon Period 2Beacon Periods 4 Beacon Periods )

(iv) Power Save Schedule (PSS) the combination of thevalues of the PSP and of the Awake Widow durationTo communicate with a station in Power Save modeother stations in the logical network (AVLN) need toknow its PSS

Potentially the specification allows aggressive PSSs con-stituted by an Awake Window duration of 15ms and a PSPof 1024 Beacon Periods that will cause over 99 energysaving compared toHomePlugAV In practice some in-homeapplications will require lower latency and response timeand a balance will take place reducing the mentioned gainThis is particular appealing for applications that foresee aPLC utilization that is variable during the day (for instancelarge utilization in daylight time and small utilization duringnight period) It is worth highlighting that the HomePlugAV2 specification is flexible in allowing each station in anetwork to have a different PSS Given these remarks in orderto enable efficient Power Save operation without causingdifficulties to regular communication all the stations in anetwork need to know the PSSs of the other stations Thenetwork Central Coordinator (CCo) has a key role since itgrants the requests of the different stations to enter and exitfromPower Savemode operationMoreover it distributes thedifferent PSSs to all the stations in the networkWhen neededa CCo can

(i) optionally disable Power Save mode for all stations ofthe AVLN

(ii) optionally wake up a station in Power Save mode

The shared knowledge of the PSS allows stations commu-nicating during the common Awake Windows (the Home-Plug AV2 and HomePlug Green PHY specifications have

Beacon period (BP)

Time

Time

Time

Time

Awake Window

Station A

Station B

Station C

Station D

Start of first CSMA allocation in beacon period

BPCn

t=0times

010

BPCn

t=0times

011

BPCn

t=0times

012

BPCn

t=0times

013

BPCn

t=0times

014

Figure 18 Example of Power Save operation in HomePlug AV2 andHomePlug Green PHY

Preamble Carrier

Frame Control Carrier

Data Carrier

OFDM symbol 1 OFDM symbol 2 OFDM symbol N

middot middot middot middot middot middot middot middot middotmiddot middot middot

Figure 19 Short Delimiter

structured the protocol insuring that at least one superposi-tion of all the Awake Windows occurs) This overlap intervalcan also be used for transmission of information that needsto be received by all stations within the AVLN

Figure 18 shows an example of Power Save Schedule ofthe four stations A B C and D All stations save morethan 75 energy compared to HomePlug AV Note that inthis example stations A and B can communicate once every2 Beacon Periods Moreover all the stations are always awakeat the same time once every 4 Beacon Periods thus preservingcommunication possibility

42 Short Delimiter and Delayed Acknowledgement TheShort Delimiter and Delayed Acknowledgement featureswere added to HomePlug AV2 to improve efficiency byreducing the overhead associated with transmitting payloadsover the power line channel In HomePlug AV this overheadresults in relatively poor efficiency for transmission controlprotocol (TCP) payloads One goal that was achieved with


AV11Delimiter Payload

Payload

AV11delimiter

AV11delimiter

SD

PRSAV11

acknowledgement

Short Delimiter basedacknowledgement

Long MPDU using a AV11 delimiter


RIFS CIFSRIFS

AV11delimiter

Figure 20 Short delimiter efficiency improvement

Data (2nd) Data (last) SACK

RIFS


RIFS

Acknowledge segments that endin the last data symbol in the

next SACK transmissionAcknowledge segments in all but thelast data symbol in the immediately

following SACK transmission

Preamble +FC + data

Preamble +FC + data

middot middot middot middot middot middot

Figure 21 Delayed Acknowledgement

these new features was TCP efficiency that improved to berelatively close to that of UDP

In order to send a packet carrying payload data over anoisy channel signaling is required for a receiver to detectthe beginning of the packet and to estimate the channel sothat the payload can be decoded and additional signaling isneeded to acknowledge the payloadwas received successfullyInterframe spaces are also required between the payloadtransmission and the acknowledgement for the processingtime at the receiver to decode and check the payload foraccurate reception and to encode the acknowledgementThisoverhead is even more significant for TCP payload since theTCP acknowledgement payload must be transmitted in thereverse direction

421 Short Delimiter The delimiter specified in HomePlugAV contains the Preamble and Frame Control symbols and isused for the beginning of data PPDUs as well as for imme-diate acknowledgements The length of the HomePlug AVdelimiter is 1105120583s and can represent a significant amountof overhead for each channel access A new single OFDMsymbol delimiter is specified in HomePlug AV2 to reduce theoverhead associated with delimiters by reducing the lengthto 555 120583s Figure 19 shows that every fourth carrier in thefirst OFDM symbol is assigned as a Preamble Carrier and theremaining carriers encode the Frame Control The followingOFDM symbols encode data the same as in HomePlug AV

Figure 20 demonstrates the efficiency improvement whenthe HomePlug AV2 Short Delimiter is used for the acknowl-edgement of a CSMA Long MPDU (MAC Protocol DataUnit) compared to the HomePlug AV delimiter Not only is

the length of the delimiter reduced from 1105 to 555120583s theResponse Inter-Frame Space (RIFS) and Contention Inter-Frame Space (CIFS) can also be reduced to 5 120583s and 10 120583srespectively Reduction of RIFS requires Delayed Acknowl-edgement which is described in Section 422 Backwardcompatibility when contending with HomePlug AV devicesis maintained by indicating the same length field for virtualcarrier sense in both cases so that the position of the priorityresolution symbols (PRS) contention remains the same Afield in the Frame Control of the Long MPDU indicates theShort Delimiter format to a HomePlug AV2 device so that itcan correctly determine the length of the payload

422 Delayed Acknowledgement The processing time todecode the last OFDM symbol and encode the acknowl-edgement can be quite high thus requiring a rather largeResponse Inter-Frame Space (RIFS) In HomePlug AV sincethe preamble is a fixed signal the preamble portions ofthe acknowledgement can be transmitted while the receiveris still decoding the last OFDM symbol and encoding thepayload for the acknowledgement With the Short Delimiterthe preamble is encoded in the same OFDM symbol as theFrame Control for the acknowledgement so the RIFS wouldneed to be larger than for HomePlug AV eliminating muchof the gain the Short Delimiter provides

Delayed Acknowledgement solves this problem byacknowledging the segments ending in the last OFDMsymbol in the acknowledgement transmission of thenext PPDU as shown in Figure 21 This permits practicalimplementations with a very small RIFS reducing the RIFSoverhead close to zero HomePlug AV2 also allows the


SOF SOF SACK

SOF indicatesMPDU burst

B acknowledgesdirectly to A

Segments from A are retransmitted by R to BBad segments are replaced with dummy segments

Normal channelcontention

PRSCRSPayload (ArarrR) Payload (RrarrB)

Figure 22 Immediate repeating channel access for CSMA

option of delaying acknowledgement for segments endingin the second to last OFDM symbol to provide flexibility forimplementers

43 Immediate Repeating HomePlug AV2 supports repeat-ing and routing of traffic to not only handle hidden nodesbut also to improve coverage (ie performance on the worstchannels)

With HomePlug AV2 hidden nodes are extremely rareHowever some links may not support the data rate requiredfor some applications such as a 3D HD video stream In anetwork where there are multiple HomePlug AV2 devicesthe connection through a repeater typically provides a higherdata rate than the direct path for the poorest 5 of channels

Immediate Repeating is a new feature in HomePlug AV2that enables high efficient repeating Immediate Repeatingprovides a mechanism to use a repeater with a single chan-nel access and the acknowledgement does not involve therepeater As shown in Figure 22 station A transmits to therepeater R In the same channel access repeater R transmitsall payload received from station A to station B B sends anacknowledgement directly to A With this approach latencyis actually reduced with repeating assuming the resultingdata rate is higher the obvious criteria for using repeatingin the first place Also resources required by the repeaterare minimized since the repeater uses and immediately freesmemory it would require for receiving payload destined forit Also the receiver has no retransmission responsibility forfailed segments

5 Coexistence with Other PLC Technologies

51 Inter System Protocol Intersystem Protocol (ISP) allowscoexistence between noninteroperable devices sharing thesame power line medium Using the current ISP protocolnoninteroperable devices are able to coexist The HomePlugAV2 will operate in a 1901-FFT mode [5] in order to coexistwith the other systems in this case the TDM slot allocated forthe 1901-FFT is to be used by the HomePlug AV2 system

The ISP protocol allows a TDM scheme to be imple-mented between coexisting in-home systems and betweencoexisting in-home and access systems Each of the PLCsystem categories is allocated a particular ISP window in around-robin fashion The allocation is determined by (1) thenumber of systems on the power line (2) the type of thesystems present and (3) the access systembandwidth requestas defined in the 1901 standard [34]

The TDM synchronization period for the in-home andaccess systems is defined with the parameter 119879

119867in Figure 23

There are four ISP windows within a single 119879119867

periodEach ISP window is further divided into three TDM units(TDMU) so there are a total of twelve TDMUs in each 119879

119867

period labeled TDMU0 through TDMU11 Each TDMUis further divided into eight TDM slots (TDMS) labeledTDMS0 through TDMS7

Figure 23 illustrates the TDM partitioning relative to theAC line cyclesThe ISP window is used to generate and detectthe ISP signal that is allocated within the first TDMS0 inTMDU0 TMDU3 TMDU6 and TDMU9The purposeand nature of the ISP signals will be described later Notethe term Beacon Period in the HomePlug AV2 specificationis similar to the 2 AC line cycles of the TDMU

52 ISP Signals Coexistence signaling is carried out bythe use of periodically repeating ISP signals within theISP windows The signals are used to convey informationon coexisting system presence resource requirements andresynchronization request Each PLC system category isallocated a particular ISP window in a round-robin fashionas illustrated in Figure 23

The ISP signal is transmitted using a range of designatedphases that convey a range of information to be used by thesystem This set of instantaneous information is termed theNetwork Status that defines the allocation of resources to eachcoexisting system

The ISP signal is merely detected By monitoring the ISPsignal transmitted within the ISP windows allocated to othersystems a coexisting system is able to determine the numberand type of coexisting systems present on the line and theirresource requirements Similarly by monitoring the signalwithin its own ISP window a coexisting system is able todetect a resynchronization request from one of the othercoexisting systems

The ISP signal consists of 16 consecutive OFDM sym-bols Each OFDM symbol is formed by a set of ldquoall-onerdquobinary phase shift keying (BPSK) modulated onto the carrierwaveforms using IFFT and multiplied by a window functionto reduce out-of-band energy complying with the transmitspectrum requirement Since all devices send the signalsimultaneously the ISP signal must be sent with 8 dB lesspower than the normal transmission

Timing parameter that is used for generating an ISP signalis described in Figure 24

53 Startup and Resynchronization Procedures The TDMsynchronization scheme mentioned above is used such thateach PLC system shares the mediumwithout interfering withone another However it is possible that two or more systemsare synchronized to two or more different mutually visibleISP sequences [35] In such cases in order to prevent mutualinterference it is important that they resynchronize to thesame ISP sequence

In other words whenever a HomePlug AV2 device startsup or restarts it needs to be aware of the presence of any othersystems with which it is able to coexist Accordingly a startup


TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH

1 TDMU = 2 AC cycles

ISP119879

Figure 23 Time Division Multiplexing on ISP

Timing Parameters

Windowing duration8192

16 OFDM symbols

Time ( s)

minus 2times

le 1024

Figure 24 ISP Signal Timing Parameter

and resynchronization procedure is defined within the ISPprotocol that allows the starting system to synchronize withan existing system

6 Gain of HomePlug AV2 Compared toHomePlug AV

The AV TWG has evaluated the performance of the Home-Plug AV2 specification this activity has been fundamental inorder to see if the produced specification meets the require-ments of all the stakeholders The following tables show theperformance improvement as compared to HomePlug AV interms of coverage These preliminary results are based on a6-home field test in Florida home sizes 1900ndash3300 sq ft

Table 1 presents the results in a 2-node network scenario95 of nodes experiment a throughput improvement greater

Table 1 Improvement of HomePlug AV2 in a 2-node network

Coverage based on UDPthroughput

Percentage of throughputimprovement of HomePlug AV2compared to HomePlug AV

95 gt1365 gt220




99 gt1315 gt173

than 136 compared to HomePlug AV (which means aperformance enhancement by a factor nearly equal to 24)Benefits are even higher when considering themost favorableconnections (see the improvement at the 5 coverage value)Table 2 considers a 4-node scenario where 3 streams carryingdifferent data are transmitted from one source (eg a Set-Top Box) to 3 different destinations (eg TVs) In this casethe improvement in the aggregate throughput is relevant forthe 99 of networks compared to HomePlug AV (more than131)

Note that the benefits of the HomePlug AV2 technologyare expected to be greater (which explains the ldquogtrdquo symbol)than the ones shown in Tables 1 and 2 since for instance a2times2MIMOwas tested in Florida 2times3 or 2times4MIMOwouldlikely provide better performance

Another interesting figure is the theoretical maximumPHY throughput for the system for different options of thestandard (Table 3) This number represents the throughputof transmitted bits on the PHY layer for optimum channel


Table 3 Maximum PHY rate computation

System configuration(North American tone mask) Max PHY rate

HomePlug AV (18ndash30MHz)(917 carriers 10 bitscarr 556 120583s GI) 197Mbps

IEEE 1901 (18ndash50MHz)(1974 carriers 12 bitscarr 16 120583s GI) 556Mbps

HomePlug AV2 SISO (18ndash8613MHz)(3455 carriers 12 bitscarr 00 120583s GI) 1012Mbps

HomePlug AV2 MIMO (18ndash8613MHz)(3455 carriers 12 bitscarr 00 120583s GI 2 streams) 2024Mbps

conditions and gives an idea of the benefits of differentfeatures It can be seen that if the full frequency range isused HomePlug AV2 provides a 1 Gbps throughput in SISOconfiguration and 2Gbps in a MIMO configuration

7 Conclusion

In this paper an overview of HomePlug AV2 has beenpresented The overall system architecture and the key tech-nical HomePlug AV2 improvements introduced at PHY andMAC layers have been described It has been also shownthe related performance improvements were achieved byHomePlug AV2 while ensuring both backward compatibilityversus HomePlug AV and the coexistence with other powerline technologies

The HomePlug AV2 performance presented in this workhas been assessed by AV TWG through simulations based onfield measurements

The results show the significant benefits introduced bythe new set of HomePlug AV2 features both in terms ofachievable data rate and coverage

References

[1] HomePlug Alliance httpwwwhomeplugorg[2] HomePlug Alliance HomePlug AV White Paper httpwww

homeplugorg[3] HomePlug Alliance HomePlug AV Specification Version 20

January 2012[4] HomePlug Alliance HomePlug GreenPHY the Standard

for In-Home Smart Grid Powerline Communicationshttpwwwhomeplugorg

[5] IEEE Standard 1901-2010 IEEE Standard for Broadband overPower Line Networks Medium Access Control and PhysicalLayer Specifications httpstandardsieeeorgfindstdsstand-ard1901-2010html 2010

[6] ETSI TR 101 562 PowerLine Telecommunications (PLT) 19MIMO PLT Part 1 Measurement Methods of MIMO PLThttpwwwetsiorgdeliveretsi tr101500 10159910156201010301 60tr 10156201v010301ppdf 2012

[7] ETSI TR 101 562 PowerLine Telecommunications (PLT)MIMO PLT Part 2 Setup and Statistical Results of MIMOPLT EMI Measurements httpwwwetsiorgdeliveretsi tr101500 10159910156202010201 60tr 10156202v010201ppdf2012

[8] ETSI TR 101 562 PowerLine Telecommunications (PLT)MIMO PLT Part 3 Setup and Statistical Results of MIMOPLT Channel and Noise Measurements httpwwwetsiorgdeliveretsi tr101500 10159910156203010101 60tr 10156203v010101ppdf 2012

[9] D Schneider A Schwager W Baschlin and P Pagani ldquoEuro-pean MIMO PLC field measurements channel analysisrdquo inProceedings of the IEEE International Symposium on PowerLine Communications and its Applications (ISPLC rsquo12) BeijingChina March 2012

[10] P Pagani R Hashmat A Schwager D Schneider and WBaschlin ldquoEuropean MIMO PLC field measurements noiseanalysisrdquo in Proceedings of the IEEE International Symposiumon Power Line Communications and its Applications (ISPLC rsquo12)Beijing China March 2012

[11] D Veronesi R Riva P Bisaglia et al ldquoCharacterization of in-home MIMO power line channelsrdquo in Proceedings of the IEEEInternational Symposium on Power Line Communications andIts Applications (ISPLC rsquo11) pp 42ndash47 Udine Italy April 2011

[12] D Rende A Nayagam K Afkhamie et al ldquoNoise correlationand its effect on capacity of inhome MIMO power line chan-nelsrdquo in Proceedings of the IEEE International Symposium onPower Line Communications and Its Applications (ISPLC rsquo11) pp60ndash65 Udine Italy April 2011

[13] R Hashmat P Pagani A Zeddam and T Chonavel ldquoMIMOcommunications for inhome PLC Networks measurementsand results up to 100MHzrdquo in Proceedings of the 14th IEEEInternational Symposium on Power Line Communications andits Applications (ISPLC rsquo10) pp 120ndash124 Rio de Janeiro BrazilMarch 2010

[14] D Schneider Inhome power line communications using multipleinput multiple output principles [Doctoral thesis] University ofStuttgart Stuttgart Germany 2012

[15] R Hashmat P Pagani A Zeddam and T Chonavel ldquoA channelmodel for multiple input multiple output in-home power linenetworksrdquo in Proceedings of the IEEE International Symposiumon Power Line Communications and Its Applications (ISPLC rsquo11)pp 35ndash41 Udine Italy April 2011

[16] R Hashmat P Pagani A Zeddam and T Chonavel ldquoAnalysisand modeling of background noise for inhome MIMO PLCchannelsrdquo in Proceedings of the 14th IEEE International Sympo-siumonPower LineCommunications and its Applications (ISPLCrsquo12) pp 120ndash124 Beijing China March 2012

[17] F Versolatto andAM Tonello ldquoAMIMOPLC random channelgenerator and capacity analysisrdquo in Proceedings of the IEEEInternational Symposium on Power Line Communications andIts Applications (ISPLC rsquo11) pp 66ndash71 Udine Italy April 2011

[18] R Hashmat P Pagani T Chonavel and A Zeddam ldquoA timedomain model of background noise for In-home MIMO PLCnetworksrdquo IEEE Transactions on Power Delivery vol 27 no 4pp 2082ndash2089 2012

[19] A Schwager Powerline communications significant technologiesto become ready for integration [Doctoral thesis] University ofDuisburg-Essen Essen Germany 2010

[20] A Paulraj R Nabar and D Gore Introduction To Space-TimeWireless Communications Cambridge University Press NewYork NY USA 2003

[21] L Stadelmeier D Schneider D Schill A Schwager and JSpeidel ldquoMIMO for inhome power line communicationsrdquo inProceedings of the 7th International ITG Conference on Sourceand Channel Coding (SCC rsquo08) Ulm Germany January 2008


[22] A Canova N Benvenuto and P Bisaglia ldquoReceivers forMIMO-PLC channels throughput comparisonrdquo in Proceedingsof the 14th IEEE International Symposium on Power LineCommunications and its Applications (ISPLC rsquo10) pp 114ndash119Rio de Janeiro Brazil March 2010

[23] S Katar B Mashburn K Afkhamie H Latchman and RNewman ldquoChannel adaptation based on cyclo-stationary noisecharacteristics in PLC systemsrdquo in Proceedings of the IEEEInternational SymposiumonPower LineCommunications and ItsApplications (ISPLC rsquo06) pp 16ndash21 Orlando Fla USA March2006

[24] A M Tonello J A Cortes and S DrsquoAlessandro ldquoOptimaltime slot design in an OFDM-TDMA system over power-linetime-variant channelsrdquo in Proceedings of the IEEE InternationalSymposium on Power Line Communications and its Applications(ISPLC rsquo09) pp 41ndash46 Dresden Germany April 2009

[25] A Scaglione P Stoica S Barbarossa G B Giannakis and HSampath ldquoOptimal designs for space-time linear precoders anddecodersrdquo IEEE Transactions on Signal Processing vol 50 no 5pp 1051ndash1064 2002

[26] A R Horn and R C Johnson Matrix Analysis CambridgeUniversity Press New York NY USA 1985

[27] A Lozano A M Tulino and S Verdu ldquoOptimum powerallocation for parallel gaussian channels with arbitrary inputdistributionsrdquo IEEE Transactions on InformationTheory vol 52no 7 pp 3033ndash3051 2006

[28] S D rsquoAlessandro A M Tonello and L Lampe ldquoAdaptivepulse-shaped OFDM with application to in-home power linecommunicationsrdquo Telecommunication Systems Journal vol 51no 1 pp 31ndash1311 2011

[29] F J Harris ldquoOn the use of windows for harmonic analysis withthe discrete Fourier transformrdquo Proceedings of the IEEE vol 66no 1 pp 51ndash83 1978

[30] K H Afkhamie H Latchman L Yonge T Davidson and RNewman ldquoJoint optimization of transmit pulse shaping guardinterval length and receiver side narrow-band interferencemitigation in the HomePlugAV OFDM systemrdquo in Proceedingsof the IEEE 6th Workshop on Signal Processing Advances inWireless Communications (SPAWC rsquo05) pp 996ndash1000 NewYork NY USA June 2005

[31] A M Tonello S DrsquoAlessandro and L Lampe ldquoCyclic prefixdesign and allocation in bit-loaded OFDM over power linecommunication channelsrdquo IEEE Transactions on Communica-tions vol 58 no 11 pp 3265ndash3276 2010

[32] CENELEC ldquoPower line communication apparatus used in lowvoltage installationsmdashradio disturbance characteristicsmdashlimitsandmethods of measurementmdashpart 1 apparatus for inhomeuserdquo Final Draft European Standard FprEN 50561-1 2011

[33] A Schwager W Baschlin J L Gonzalez Moreno et al ldquoEuro-pean MIMO PLC field measurements overview of the ETSISTF410 campaign amp EMI analysisrdquo in Proceedings of the IEEEInternational Symposium on Power Line Communications andits Applications (ISPLC rsquo12) Beijing China March 2012

[34] IEEE Standard 1901-2010 IEEE Standard for Broadband overPower Line Networks Medium Access Control and PhysicalLayer Specifications Chapter 16 ldquoInter System Protocol (ISP)rdquo2010

[35] IEEE Standard 1901-2010 IEEE Standard for Broadband overPower Line Networks Medium Access Control and PhysicalLayer Specifications Annex R ldquoResynchronization examplerdquo2010

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Active and Passive Electronic Components

Control Scienceand Engineering

Journal of



RotatingMachinery


Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Submit your manuscripts athttpwwwhindawicom

VLSI Design



Shock and Vibration


Civil EngineeringAdvances in

Acoustics and VibrationAdvances in



Electrical and Computer Engineering

Journal of

Advances inOptoElectronics


Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of


Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014


Chemical EngineeringInternational Journal of Antennas and

Propagation




Navigation and Observation



DistributedSensor Networks



for in-home power line communication To meet the futuremarket needs in January 2012 the HomePlug Alliance pub-lished the HomePlug AV2 specification [3] HomePlug AV2enables Gigabit-class connection speeds by leveraging on theexisting power line wires while remaining fully interoperablewith other technologies for in-home connectivity (HomePlugAV [2] HomePlug Green PHY [4] and IEEE 1901 [5]) TheAlliancersquos AV Technical Working Group (AV TWG) definednew features at both the PHY and MAC layers These havebeen introduced in theHomePlugAV2 specification based onextensive field tests conducted in real home scenarios acrossdifferent countriesThe field results obtained by the AVTWGvalidated the HomePlug AV2 claimed performance both interms of achievable data rate and coverage

In this paper we highlight the key differentiating Home-Plug AV2 features compared to the HomePlug AV technol-ogy At the physical (PHY) layer HomePlug AV2 includesthe following (i) Multiple-Input Multiple-Output (MIMO)signaling with Beamforming to offer the benefit of improvedcoverage throughout the home especially on highly atten-uated channels MIMO enables HomePlug AV2 devices totransmit on any two-wire pairs within three-wire configura-tions comprising Line (L) Neutral (N) and Protective Earth(PE) (the coupling is done in the MIMO Analog Front End(AFE) blocks in Figure 1) (ii) Extended Frequency Band upto 86 MHz to increase the throughput especially at the lowto mid coverage percentages (part of IFFTFFT (1024 8192)andMapper blocks in Figure 1) (iii) Efficient Notching allowstransmitters to create extremely sharp frequency notches IfElectromagneticCompatibility (EMC) regulationwill requirea fragmented communication spectrum the throughput lossby excluded frequencies can be minimized (part of PowerAllocation and Window and Overlap blocks in Figure 1)(iv) Power back-off to increase the HomePlug AV2 datarate while reducing the electromagnetic emissions (part ofPower Allocation blocks and the AFEs in Figure 1) (v) EMCFriendly Power Boost to optimize the transmit power bymonitoring the input port reflection coefficient (known as the11987811

parameter) at the transmitting modem (vi) AdditionalPHY Improvements comprising higher order QuadratureAmplitude Modulation (4096-QAM) (part of Mapper andDemodulator blocks in Figure 1) higher Code Rates (89code rate) (part of Turbo Convolutional Encoder in Figure 1)and smaller guard intervals (part of Cyclic Prefix blocks inFigure 1) to assist better peak data rates At the MediumAccess Control (MAC) layer HomePlug AV2 includes thefollowing (i) Power Save mode to improve energy efficiencywhen the device is in standby (ii) Short Delimiter to reducethe overhead of the transmission shortening the Preambleand Frame Control symbols (iii) Delayed Acknowledgementsto increase the overall transmission efficiency by reducing theInter Frame Spacings (iv) Immediate Repeating to expand thecoverage by repeating the signal on paths with better Signalto Noise Ratio (SNR) characteristics

All the features listed above improve the Quality ofService of AV2 power line modems by improving coverageand robustness of communication links

The following sections provide technical details for all theabove mentioned features Moreover the AV TWG evaluated

the performance of the HomePlug AV2 systemThe adoptionof all the above listed features provides a significant gain ofHomePlug AV2 compared to HomePlug AV The remainderof this paper is organized as follows Section 2 presentsthe overall HomePlug AV2 system architecture precededby a brief overview of the HomePlug AV technology Thenew PHY and MAC layer technical features are detailed inSections 3 and 4 respectively Section 5 explains how thetechnology coexistence is dealt with Section 6 summarizesthe performance gain of HomePlug AV2 compared to Home-Plug AV and Section 7 concludes this introduction to theHomePlug AV2 technology

2 System Architecture

21 A Brief Overview of HomePlug AV HomePlug AVemploys PHY and MAC technology that provides a 200-Mbps class power line networking capability The PHYoperates in the frequency range of 2ndash28MHz uses windowedOrthogonal Frequency Division Multiplexing (OFDM) anda powerful Turbo Convolutional Code (TCC) that providesrobust performance within 05 dB of Shannonrsquos limit Win-dowed OFDM provides more than 30 dB spectrum notchingOFDM symbols with 917 usable carriers (tones) are usedin conjunction with a flexible guard interval Modulationdensities from BPSK to 1024 QAM are adaptively applied toeach carrier based on the channel characteristic between thetransmitter (Tx) and the receiver (Rx)

On the MAC layer HomePlug AV provides a Quality ofService (QoS) connection oriented contention-free serviceon a periodic TimeDivisionMultiple Access (TDMA) alloca-tion and a connectionless prioritized contention-based ser-vice on a Carrier Sense Multiple AccessCollision Avoidance(CSMACA) allocation The MAC receives MAC ServiceData Units (MSDUs) and encapsulates them with a headeroptional Arrival Time Stamp (ATS) and a checksum to createa stream ofMAC framesThe stream is then divided into 512-octet segments encrypted and encapsulated into serializedPHY Blocks (PBs) and packed as MAC Protocol Data Units(MPDUs) to the PHYunitwhich then generates the final PHYProtocol Data Unit (PPDU) to be transmitted onto the powerline [2]

HomePlug AV2 enhances significantly the capabilityabove to accommodate new generation of multimedia appli-cations with Gigabit performance

22The HomePlug AV2 Technology TheHomePlug system isspecified for in-home communication adapted to the powerline channel The in-home communications are establishedwith Time Division Duplexing (TDD) mechanism to allowfor symmetric communication between peers as opposedto the classical access system in ADSL with two differentdownstream and upstream throughputs

The PHY layer employs OFDM modulation scheme forbetter efficiency and adaptability to the channel impairments(such as being frequency selective and suffering fromnarrow-band interference and impulsive noise) The HomePlug AV2OFDMparameters correspond to a systemwith 4096 carriers





Scrambler

MapperTurbo


Channel and ROBO

Interleaver

Insert Preamble

MIMOAFE

Power line


Turbo Convolutional

Decoder

FrameControl

deinterleaver

1024 Point FFT

AGC

Time Sync

Frame Control

Demodulator

MIMOAFE


ROBOdeinterleaver

Tx

Rx




DescramblerMIMO

Equalizer

Frame Control

Interleaver


Copier



Copies



Payload Data in

Turbo Convolutional

Decoder


IFFT(10248192)


Overlap




Demodulator

8192 Point

FFT(1)

8192 Point

Receive Channels


PhaseShifter


Encoder

FFT( )


101 Frame Control


Data out

Payload Data out

AV2

Pow

er A

lloca

tion

MIM

O P

reco

ding

119873119877

119873119877

119873119877

2-Transmit channels


















Tx

PLCmodem

1 1

2 23 3

4

PLCchannel

L

N

PE

Ground

Rx

PLCmodem


0 10 20 30 40 50 60 70 80minus 90

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

Frequency (MHz)



119891

|11987821|

(dB)







119877Rx ports




L-PEL-PE

L-N L-N

CM

N-PE

(a)

1

2

1

2

3

4

0

0

D U

VH

(b)



21(for-


21curves





times 119873119879


H (119888) =[[

[

ℎ11

(119888) sdot sdot sdot ℎ1119873119879

(119888)

ℎ1198731198771

(119888) sdot sdot sdot ℎ119873119877119873119879

(119888)

]]

]

(1)







H (119888) = U (119888)D (119888)V(119888)119867 (2)


0

0

10 20 30 40 50 60 70 80minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

Frequency (MHz)



119891

|11987821|

(dB)














F = VP (3)


Mapper

Mapper

MIMO Power


IFFTMIMO Pre-Coding

(10248192)

IFFT(10248192)

VCompute V

index index

= V2times 21199041

1199042

1199091

1199092

1199041

1199042

1199091

1199092

120595 120579











5 10 15 20 25 300

5

10

15

20

25

30

35

40

45

50SN

R (d

B)



(a)

5 10 15 20 25 300

5

10

15

20

25

30

35

40

45

50

SNR

(dB)



(b)

88

88

888

88

10

1010

1010

10

1010

12 12

1212

12

1414

14

14

16

16

16

181818

2020

2222 24262830320

1

2

3

4

10

15

20

25

30

0 05 151

11 dB

minus 4

minus 3

minus 2

minus 1


SNR1 ( θH)


120595

120595

120579

(c)

8 8

8 88

888

10

10

1010

1010

10

1010

1212

1212 12

1212

1212 12

1414

14 14

1414

14 14

16

16 16

16

16 16

1818

18

181818

20

20

20

20

2222

2222

24

24

26

26

28

28

30

30

32

32

0

1

2

3

4

10

15

20

25

30

0 05 151

8 dB

minus 4

minus 3

minus 2

minus 1


θ

SNR2 ( θH)


120595

120595

(d)




V = [v1 v2] = [

11990711

11990712

11990721

11990722

] = [cos120595 sin120595

minus119890119895120579 sin120595 119890

119895120579 cos120595] (4)






=


are orthogonal


minus119895120579119890119895120579

= 0 (5)




W = H119901 = (H119867H)minus1

H119867 (6)


W = V119867H119901 = Dminus1U119867 (7)


SNR1= 120588

1

1003817100381710038171003817w11003817100381710038171003817

2 SNR

2= 120588

1

1003817100381710038171003817w21003817100381710038171003817

2 (8)
















Atte

nuat

ion

(dB)

times 107

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20


PSD

(dBm

Hz)


minus 160

minus 150

minus 140

minus 130

minus 120

minus 110

minus 100





0 10 20 30 40 50 60 70 80 90 100

0

Frequency (kHz)

Mag

nitu

de (d

B)



minus 100

minus 90

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

55 dB58 dB

27 dB42 dB 32 dB

13 dB






Copy and window

Copy and window



Flat guard

interval

FFT section


= 0 = RI

RIRI GI

TI2

TI2

TI2

TI2

I2

RI2

OFDM symbol


115 12 125 13 135 14

0

5

10

Frequency (MHz)

Pow

er (d

B)

10 carriers notch

543

2Singlecarriernotch

minus 30

minus 25

minus 20

minus 15

minus 10

minus 5

= 0= 001= 003125

= 00625= 0121








RI = 120573119879s (9)


119879119864= (1 + 120573) sdot 119879s (10)




















Frequency (Hz)

PSD

(dBm

Hz)


2 4 6 8 100times 107

A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 5 dB

SNR

=35

dB

(a)



times 107PS

D (d

BmH

z)A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 10 dBSNR

=30

dB

(b)







11987811


11 and






11
















(1

1 minus100381610038161003816100381611987811 (119896)

1003816100381610038161003816

2)

minus119872(119896) 0) IMCmax)

(11)


11


11 and









0

02

04

06

08

1


CDF

of11119878


0 2 4 6 8 10 12 14 160

02

04

06

08

1

IMC (dB)

CDF

of IM

C









1 15 2 25 3 35 4 45 50

01

02

03

04

05

06

07

08

09

1

Perc

entil

e

Low EMIvalues

High EMIvalues





6 dB






















Beacon period (BP)

Time

Time

Time

Time

Awake Window

Station A

Station B

Station C

Station D


BPCn

t=0times

010

BPCn

t=0times

011

BPCn

t=0times

012

BPCn

t=0times

013

BPCn

t=0times

014


Preamble Carrier


Data Carrier









Payload

AV11delimiter

AV11delimiter

SD

PRSAV11

acknowledgement




RIFS CIFSRIFS

AV11delimiter



RIFS


RIFS




Preamble +FC + data

Preamble +FC + data











SOF SOF SACK















119867in Figure 23



119867











TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation













Scrambler

MapperTurbo


Channel and ROBO

Interleaver

Insert Preamble

MIMOAFE

Power line


Turbo Convolutional

Decoder

FrameControl

deinterleaver

1024 Point FFT

AGC

Time Sync

Frame Control

Demodulator

MIMOAFE


ROBOdeinterleaver

Tx

Rx




DescramblerMIMO

Equalizer

Frame Control

Interleaver


Copier



Copies



Payload Data in

Turbo Convolutional

Decoder


IFFT(10248192)


Overlap




Demodulator

8192 Point

FFT(1)

8192 Point

Receive Channels


PhaseShifter


Encoder

FFT( )


101 Frame Control


Data out

Payload Data out

AV2

Pow

er A

lloca

tion

MIM

O P

reco

ding

119873119877

119873119877

119873119877

2-Transmit channels


















Tx

PLCmodem

1 1

2 23 3

4

PLCchannel

L

N

PE

Ground

Rx

PLCmodem


0 10 20 30 40 50 60 70 80minus 90

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

Frequency (MHz)



119891

|11987821|

(dB)







119877Rx ports




L-PEL-PE

L-N L-N

CM

N-PE

(a)

1

2

1

2

3

4

0

0

D U

VH

(b)



21(for-


21curves





times 119873119879


H (119888) =[[

[

ℎ11

(119888) sdot sdot sdot ℎ1119873119879

(119888)

ℎ1198731198771

(119888) sdot sdot sdot ℎ119873119877119873119879

(119888)

]]

]

(1)







H (119888) = U (119888)D (119888)V(119888)119867 (2)


0

0

10 20 30 40 50 60 70 80minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

Frequency (MHz)



119891

|11987821|

(dB)














F = VP (3)


Mapper

Mapper

MIMO Power


IFFTMIMO Pre-Coding

(10248192)

IFFT(10248192)

VCompute V

index index

= V2times 21199041

1199042

1199091

1199092

1199041

1199042

1199091

1199092

120595 120579











5 10 15 20 25 300

5

10

15

20

25

30

35

40

45

50SN

R (d

B)



(a)

5 10 15 20 25 300

5

10

15

20

25

30

35

40

45

50

SNR

(dB)



(b)

88

88

888

88

10

1010

1010

10

1010

12 12

1212

12

1414

14

14

16

16

16

181818

2020

2222 24262830320

1

2

3

4

10

15

20

25

30

0 05 151

11 dB

minus 4

minus 3

minus 2

minus 1


SNR1 ( θH)


120595

120595

120579

(c)

8 8

8 88

888

10

10

1010

1010

10

1010

1212

1212 12

1212

1212 12

1414

14 14

1414

14 14

16

16 16

16

16 16

1818

18

181818

20

20

20

20

2222

2222

24

24

26

26

28

28

30

30

32

32

0

1

2

3

4

10

15

20

25

30

0 05 151

8 dB

minus 4

minus 3

minus 2

minus 1


θ

SNR2 ( θH)


120595

120595

(d)




V = [v1 v2] = [

11990711

11990712

11990721

11990722

] = [cos120595 sin120595

minus119890119895120579 sin120595 119890

119895120579 cos120595] (4)






=


are orthogonal


minus119895120579119890119895120579

= 0 (5)




W = H119901 = (H119867H)minus1

H119867 (6)


W = V119867H119901 = Dminus1U119867 (7)


SNR1= 120588

1

1003817100381710038171003817w11003817100381710038171003817

2 SNR

2= 120588

1

1003817100381710038171003817w21003817100381710038171003817

2 (8)
















Atte

nuat

ion

(dB)

times 107

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20


PSD

(dBm

Hz)


minus 160

minus 150

minus 140

minus 130

minus 120

minus 110

minus 100





0 10 20 30 40 50 60 70 80 90 100

0

Frequency (kHz)

Mag

nitu

de (d

B)



minus 100

minus 90

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

55 dB58 dB

27 dB42 dB 32 dB

13 dB






Copy and window

Copy and window



Flat guard

interval

FFT section


= 0 = RI

RIRI GI

TI2

TI2

TI2

TI2

I2

RI2

OFDM symbol


115 12 125 13 135 14

0

5

10

Frequency (MHz)

Pow

er (d

B)

10 carriers notch

543

2Singlecarriernotch

minus 30

minus 25

minus 20

minus 15

minus 10

minus 5

= 0= 001= 003125

= 00625= 0121








RI = 120573119879s (9)


119879119864= (1 + 120573) sdot 119879s (10)




















Frequency (Hz)

PSD

(dBm

Hz)


2 4 6 8 100times 107

A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 5 dB

SNR

=35

dB

(a)



times 107PS

D (d

BmH

z)A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 10 dBSNR

=30

dB

(b)







11987811


11 and






11
















(1

1 minus100381610038161003816100381611987811 (119896)

1003816100381610038161003816

2)

minus119872(119896) 0) IMCmax)

(11)


11


11 and









0

02

04

06

08

1


CDF

of11119878


0 2 4 6 8 10 12 14 160

02

04

06

08

1

IMC (dB)

CDF

of IM

C









1 15 2 25 3 35 4 45 50

01

02

03

04

05

06

07

08

09

1

Perc

entil

e

Low EMIvalues

High EMIvalues





6 dB






















Beacon period (BP)

Time

Time

Time

Time

Awake Window

Station A

Station B

Station C

Station D


BPCn

t=0times

010

BPCn

t=0times

011

BPCn

t=0times

012

BPCn

t=0times

013

BPCn

t=0times

014


Preamble Carrier


Data Carrier









Payload

AV11delimiter

AV11delimiter

SD

PRSAV11

acknowledgement




RIFS CIFSRIFS

AV11delimiter



RIFS


RIFS




Preamble +FC + data

Preamble +FC + data











SOF SOF SACK















119867in Figure 23



119867











TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation



















Tx

PLCmodem

1 1

2 23 3

4

PLCchannel

L

N

PE

Ground

Rx

PLCmodem


0 10 20 30 40 50 60 70 80minus 90

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

Frequency (MHz)



119891

|11987821|

(dB)







119877Rx ports




L-PEL-PE

L-N L-N

CM

N-PE

(a)

1

2

1

2

3

4

0

0

D U

VH

(b)



21(for-


21curves





times 119873119879


H (119888) =[[

[

ℎ11

(119888) sdot sdot sdot ℎ1119873119879

(119888)

ℎ1198731198771

(119888) sdot sdot sdot ℎ119873119877119873119879

(119888)

]]

]

(1)







H (119888) = U (119888)D (119888)V(119888)119867 (2)


0

0

10 20 30 40 50 60 70 80minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

Frequency (MHz)



119891

|11987821|

(dB)














F = VP (3)


Mapper

Mapper

MIMO Power


IFFTMIMO Pre-Coding

(10248192)

IFFT(10248192)

VCompute V

index index

= V2times 21199041

1199042

1199091

1199092

1199041

1199042

1199091

1199092

120595 120579











5 10 15 20 25 300

5

10

15

20

25

30

35

40

45

50SN

R (d

B)



(a)

5 10 15 20 25 300

5

10

15

20

25

30

35

40

45

50

SNR

(dB)



(b)

88

88

888

88

10

1010

1010

10

1010

12 12

1212

12

1414

14

14

16

16

16

181818

2020

2222 24262830320

1

2

3

4

10

15

20

25

30

0 05 151

11 dB

minus 4

minus 3

minus 2

minus 1


SNR1 ( θH)


120595

120595

120579

(c)

8 8

8 88

888

10

10

1010

1010

10

1010

1212

1212 12

1212

1212 12

1414

14 14

1414

14 14

16

16 16

16

16 16

1818

18

181818

20

20

20

20

2222

2222

24

24

26

26

28

28

30

30

32

32

0

1

2

3

4

10

15

20

25

30

0 05 151

8 dB

minus 4

minus 3

minus 2

minus 1


θ

SNR2 ( θH)


120595

120595

(d)




V = [v1 v2] = [

11990711

11990712

11990721

11990722

] = [cos120595 sin120595

minus119890119895120579 sin120595 119890

119895120579 cos120595] (4)






=


are orthogonal


minus119895120579119890119895120579

= 0 (5)




W = H119901 = (H119867H)minus1

H119867 (6)


W = V119867H119901 = Dminus1U119867 (7)


SNR1= 120588

1

1003817100381710038171003817w11003817100381710038171003817

2 SNR

2= 120588

1

1003817100381710038171003817w21003817100381710038171003817

2 (8)
















Atte

nuat

ion

(dB)

times 107

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20


PSD

(dBm

Hz)


minus 160

minus 150

minus 140

minus 130

minus 120

minus 110

minus 100





0 10 20 30 40 50 60 70 80 90 100

0

Frequency (kHz)

Mag

nitu

de (d

B)



minus 100

minus 90

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

55 dB58 dB

27 dB42 dB 32 dB

13 dB






Copy and window

Copy and window



Flat guard

interval

FFT section


= 0 = RI

RIRI GI

TI2

TI2

TI2

TI2

I2

RI2

OFDM symbol


115 12 125 13 135 14

0

5

10

Frequency (MHz)

Pow

er (d

B)

10 carriers notch

543

2Singlecarriernotch

minus 30

minus 25

minus 20

minus 15

minus 10

minus 5

= 0= 001= 003125

= 00625= 0121








RI = 120573119879s (9)


119879119864= (1 + 120573) sdot 119879s (10)




















Frequency (Hz)

PSD

(dBm

Hz)


2 4 6 8 100times 107

A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 5 dB

SNR

=35

dB

(a)



times 107PS

D (d

BmH

z)A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 10 dBSNR

=30

dB

(b)







11987811


11 and






11
















(1

1 minus100381610038161003816100381611987811 (119896)

1003816100381610038161003816

2)

minus119872(119896) 0) IMCmax)

(11)


11


11 and









0

02

04

06

08

1


CDF

of11119878


0 2 4 6 8 10 12 14 160

02

04

06

08

1

IMC (dB)

CDF

of IM

C









1 15 2 25 3 35 4 45 50

01

02

03

04

05

06

07

08

09

1

Perc

entil

e

Low EMIvalues

High EMIvalues





6 dB






















Beacon period (BP)

Time

Time

Time

Time

Awake Window

Station A

Station B

Station C

Station D


BPCn

t=0times

010

BPCn

t=0times

011

BPCn

t=0times

012

BPCn

t=0times

013

BPCn

t=0times

014


Preamble Carrier


Data Carrier









Payload

AV11delimiter

AV11delimiter

SD

PRSAV11

acknowledgement




RIFS CIFSRIFS

AV11delimiter



RIFS


RIFS




Preamble +FC + data

Preamble +FC + data











SOF SOF SACK















119867in Figure 23



119867











TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










L-PEL-PE

L-N L-N

CM

N-PE

(a)

1

2

1

2

3

4

0

0

D U

VH

(b)



21(for-


21curves





times 119873119879


H (119888) =[[

[

ℎ11

(119888) sdot sdot sdot ℎ1119873119879

(119888)

ℎ1198731198771

(119888) sdot sdot sdot ℎ119873119877119873119879

(119888)

]]

]

(1)







H (119888) = U (119888)D (119888)V(119888)119867 (2)


0

0

10 20 30 40 50 60 70 80minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

Frequency (MHz)



119891

|11987821|

(dB)














F = VP (3)


Mapper

Mapper

MIMO Power


IFFTMIMO Pre-Coding

(10248192)

IFFT(10248192)

VCompute V

index index

= V2times 21199041

1199042

1199091

1199092

1199041

1199042

1199091

1199092

120595 120579











5 10 15 20 25 300

5

10

15

20

25

30

35

40

45

50SN

R (d

B)



(a)

5 10 15 20 25 300

5

10

15

20

25

30

35

40

45

50

SNR

(dB)



(b)

88

88

888

88

10

1010

1010

10

1010

12 12

1212

12

1414

14

14

16

16

16

181818

2020

2222 24262830320

1

2

3

4

10

15

20

25

30

0 05 151

11 dB

minus 4

minus 3

minus 2

minus 1


SNR1 ( θH)


120595

120595

120579

(c)

8 8

8 88

888

10

10

1010

1010

10

1010

1212

1212 12

1212

1212 12

1414

14 14

1414

14 14

16

16 16

16

16 16

1818

18

181818

20

20

20

20

2222

2222

24

24

26

26

28

28

30

30

32

32

0

1

2

3

4

10

15

20

25

30

0 05 151

8 dB

minus 4

minus 3

minus 2

minus 1


θ

SNR2 ( θH)


120595

120595

(d)




V = [v1 v2] = [

11990711

11990712

11990721

11990722

] = [cos120595 sin120595

minus119890119895120579 sin120595 119890

119895120579 cos120595] (4)






=


are orthogonal


minus119895120579119890119895120579

= 0 (5)




W = H119901 = (H119867H)minus1

H119867 (6)


W = V119867H119901 = Dminus1U119867 (7)


SNR1= 120588

1

1003817100381710038171003817w11003817100381710038171003817

2 SNR

2= 120588

1

1003817100381710038171003817w21003817100381710038171003817

2 (8)
















Atte

nuat

ion

(dB)

times 107

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20


PSD

(dBm

Hz)


minus 160

minus 150

minus 140

minus 130

minus 120

minus 110

minus 100





0 10 20 30 40 50 60 70 80 90 100

0

Frequency (kHz)

Mag

nitu

de (d

B)



minus 100

minus 90

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

55 dB58 dB

27 dB42 dB 32 dB

13 dB






Copy and window

Copy and window



Flat guard

interval

FFT section


= 0 = RI

RIRI GI

TI2

TI2

TI2

TI2

I2

RI2

OFDM symbol


115 12 125 13 135 14

0

5

10

Frequency (MHz)

Pow

er (d

B)

10 carriers notch

543

2Singlecarriernotch

minus 30

minus 25

minus 20

minus 15

minus 10

minus 5

= 0= 001= 003125

= 00625= 0121








RI = 120573119879s (9)


119879119864= (1 + 120573) sdot 119879s (10)




















Frequency (Hz)

PSD

(dBm

Hz)


2 4 6 8 100times 107

A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 5 dB

SNR

=35

dB

(a)



times 107PS

D (d

BmH

z)A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 10 dBSNR

=30

dB

(b)







11987811


11 and






11
















(1

1 minus100381610038161003816100381611987811 (119896)

1003816100381610038161003816

2)

minus119872(119896) 0) IMCmax)

(11)


11


11 and









0

02

04

06

08

1


CDF

of11119878


0 2 4 6 8 10 12 14 160

02

04

06

08

1

IMC (dB)

CDF

of IM

C









1 15 2 25 3 35 4 45 50

01

02

03

04

05

06

07

08

09

1

Perc

entil

e

Low EMIvalues

High EMIvalues





6 dB






















Beacon period (BP)

Time

Time

Time

Time

Awake Window

Station A

Station B

Station C

Station D


BPCn

t=0times

010

BPCn

t=0times

011

BPCn

t=0times

012

BPCn

t=0times

013

BPCn

t=0times

014


Preamble Carrier


Data Carrier









Payload

AV11delimiter

AV11delimiter

SD

PRSAV11

acknowledgement




RIFS CIFSRIFS

AV11delimiter



RIFS


RIFS




Preamble +FC + data

Preamble +FC + data











SOF SOF SACK















119867in Figure 23



119867











TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation














F = VP (3)


Mapper

Mapper

MIMO Power


IFFTMIMO Pre-Coding

(10248192)

IFFT(10248192)

VCompute V

index index

= V2times 21199041

1199042

1199091

1199092

1199041

1199042

1199091

1199092

120595 120579











5 10 15 20 25 300

5

10

15

20

25

30

35

40

45

50SN

R (d

B)



(a)

5 10 15 20 25 300

5

10

15

20

25

30

35

40

45

50

SNR

(dB)



(b)

88

88

888

88

10

1010

1010

10

1010

12 12

1212

12

1414

14

14

16

16

16

181818

2020

2222 24262830320

1

2

3

4

10

15

20

25

30

0 05 151

11 dB

minus 4

minus 3

minus 2

minus 1


SNR1 ( θH)


120595

120595

120579

(c)

8 8

8 88

888

10

10

1010

1010

10

1010

1212

1212 12

1212

1212 12

1414

14 14

1414

14 14

16

16 16

16

16 16

1818

18

181818

20

20

20

20

2222

2222

24

24

26

26

28

28

30

30

32

32

0

1

2

3

4

10

15

20

25

30

0 05 151

8 dB

minus 4

minus 3

minus 2

minus 1


θ

SNR2 ( θH)


120595

120595

(d)




V = [v1 v2] = [

11990711

11990712

11990721

11990722

] = [cos120595 sin120595

minus119890119895120579 sin120595 119890

119895120579 cos120595] (4)






=


are orthogonal


minus119895120579119890119895120579

= 0 (5)




W = H119901 = (H119867H)minus1

H119867 (6)


W = V119867H119901 = Dminus1U119867 (7)


SNR1= 120588

1

1003817100381710038171003817w11003817100381710038171003817

2 SNR

2= 120588

1

1003817100381710038171003817w21003817100381710038171003817

2 (8)
















Atte

nuat

ion

(dB)

times 107

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20


PSD

(dBm

Hz)


minus 160

minus 150

minus 140

minus 130

minus 120

minus 110

minus 100





0 10 20 30 40 50 60 70 80 90 100

0

Frequency (kHz)

Mag

nitu

de (d

B)



minus 100

minus 90

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

55 dB58 dB

27 dB42 dB 32 dB

13 dB






Copy and window

Copy and window



Flat guard

interval

FFT section


= 0 = RI

RIRI GI

TI2

TI2

TI2

TI2

I2

RI2

OFDM symbol


115 12 125 13 135 14

0

5

10

Frequency (MHz)

Pow

er (d

B)

10 carriers notch

543

2Singlecarriernotch

minus 30

minus 25

minus 20

minus 15

minus 10

minus 5

= 0= 001= 003125

= 00625= 0121








RI = 120573119879s (9)


119879119864= (1 + 120573) sdot 119879s (10)




















Frequency (Hz)

PSD

(dBm

Hz)


2 4 6 8 100times 107

A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 5 dB

SNR

=35

dB

(a)



times 107PS

D (d

BmH

z)A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 10 dBSNR

=30

dB

(b)







11987811


11 and






11
















(1

1 minus100381610038161003816100381611987811 (119896)

1003816100381610038161003816

2)

minus119872(119896) 0) IMCmax)

(11)


11


11 and









0

02

04

06

08

1


CDF

of11119878


0 2 4 6 8 10 12 14 160

02

04

06

08

1

IMC (dB)

CDF

of IM

C









1 15 2 25 3 35 4 45 50

01

02

03

04

05

06

07

08

09

1

Perc

entil

e

Low EMIvalues

High EMIvalues





6 dB






















Beacon period (BP)

Time

Time

Time

Time

Awake Window

Station A

Station B

Station C

Station D


BPCn

t=0times

010

BPCn

t=0times

011

BPCn

t=0times

012

BPCn

t=0times

013

BPCn

t=0times

014


Preamble Carrier


Data Carrier









Payload

AV11delimiter

AV11delimiter

SD

PRSAV11

acknowledgement




RIFS CIFSRIFS

AV11delimiter



RIFS


RIFS




Preamble +FC + data

Preamble +FC + data











SOF SOF SACK















119867in Figure 23



119867











TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










5 10 15 20 25 300

5

10

15

20

25

30

35

40

45

50SN

R (d

B)



(a)

5 10 15 20 25 300

5

10

15

20

25

30

35

40

45

50

SNR

(dB)



(b)

88

88

888

88

10

1010

1010

10

1010

12 12

1212

12

1414

14

14

16

16

16

181818

2020

2222 24262830320

1

2

3

4

10

15

20

25

30

0 05 151

11 dB

minus 4

minus 3

minus 2

minus 1


SNR1 ( θH)


120595

120595

120579

(c)

8 8

8 88

888

10

10

1010

1010

10

1010

1212

1212 12

1212

1212 12

1414

14 14

1414

14 14

16

16 16

16

16 16

1818

18

181818

20

20

20

20

2222

2222

24

24

26

26

28

28

30

30

32

32

0

1

2

3

4

10

15

20

25

30

0 05 151

8 dB

minus 4

minus 3

minus 2

minus 1


θ

SNR2 ( θH)


120595

120595

(d)




V = [v1 v2] = [

11990711

11990712

11990721

11990722

] = [cos120595 sin120595

minus119890119895120579 sin120595 119890

119895120579 cos120595] (4)






=


are orthogonal


minus119895120579119890119895120579

= 0 (5)




W = H119901 = (H119867H)minus1

H119867 (6)


W = V119867H119901 = Dminus1U119867 (7)


SNR1= 120588

1

1003817100381710038171003817w11003817100381710038171003817

2 SNR

2= 120588

1

1003817100381710038171003817w21003817100381710038171003817

2 (8)
















Atte

nuat

ion

(dB)

times 107

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20


PSD

(dBm

Hz)


minus 160

minus 150

minus 140

minus 130

minus 120

minus 110

minus 100





0 10 20 30 40 50 60 70 80 90 100

0

Frequency (kHz)

Mag

nitu

de (d

B)



minus 100

minus 90

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

55 dB58 dB

27 dB42 dB 32 dB

13 dB






Copy and window

Copy and window



Flat guard

interval

FFT section


= 0 = RI

RIRI GI

TI2

TI2

TI2

TI2

I2

RI2

OFDM symbol


115 12 125 13 135 14

0

5

10

Frequency (MHz)

Pow

er (d

B)

10 carriers notch

543

2Singlecarriernotch

minus 30

minus 25

minus 20

minus 15

minus 10

minus 5

= 0= 001= 003125

= 00625= 0121








RI = 120573119879s (9)


119879119864= (1 + 120573) sdot 119879s (10)




















Frequency (Hz)

PSD

(dBm

Hz)


2 4 6 8 100times 107

A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 5 dB

SNR

=35

dB

(a)



times 107PS

D (d

BmH

z)A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 10 dBSNR

=30

dB

(b)







11987811


11 and






11
















(1

1 minus100381610038161003816100381611987811 (119896)

1003816100381610038161003816

2)

minus119872(119896) 0) IMCmax)

(11)


11


11 and









0

02

04

06

08

1


CDF

of11119878


0 2 4 6 8 10 12 14 160

02

04

06

08

1

IMC (dB)

CDF

of IM

C









1 15 2 25 3 35 4 45 50

01

02

03

04

05

06

07

08

09

1

Perc

entil

e

Low EMIvalues

High EMIvalues





6 dB






















Beacon period (BP)

Time

Time

Time

Time

Awake Window

Station A

Station B

Station C

Station D


BPCn

t=0times

010

BPCn

t=0times

011

BPCn

t=0times

012

BPCn

t=0times

013

BPCn

t=0times

014


Preamble Carrier


Data Carrier









Payload

AV11delimiter

AV11delimiter

SD

PRSAV11

acknowledgement




RIFS CIFSRIFS

AV11delimiter



RIFS


RIFS




Preamble +FC + data

Preamble +FC + data











SOF SOF SACK















119867in Figure 23



119867











TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











W = H119901 = (H119867H)minus1

H119867 (6)


W = V119867H119901 = Dminus1U119867 (7)


SNR1= 120588

1

1003817100381710038171003817w11003817100381710038171003817

2 SNR

2= 120588

1

1003817100381710038171003817w21003817100381710038171003817

2 (8)
















Atte

nuat

ion

(dB)

times 107

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20


PSD

(dBm

Hz)


minus 160

minus 150

minus 140

minus 130

minus 120

minus 110

minus 100





0 10 20 30 40 50 60 70 80 90 100

0

Frequency (kHz)

Mag

nitu

de (d

B)



minus 100

minus 90

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

55 dB58 dB

27 dB42 dB 32 dB

13 dB






Copy and window

Copy and window



Flat guard

interval

FFT section


= 0 = RI

RIRI GI

TI2

TI2

TI2

TI2

I2

RI2

OFDM symbol


115 12 125 13 135 14

0

5

10

Frequency (MHz)

Pow

er (d

B)

10 carriers notch

543

2Singlecarriernotch

minus 30

minus 25

minus 20

minus 15

minus 10

minus 5

= 0= 001= 003125

= 00625= 0121








RI = 120573119879s (9)


119879119864= (1 + 120573) sdot 119879s (10)




















Frequency (Hz)

PSD

(dBm

Hz)


2 4 6 8 100times 107

A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 5 dB

SNR

=35

dB

(a)



times 107PS

D (d

BmH

z)A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 10 dBSNR

=30

dB

(b)







11987811


11 and






11
















(1

1 minus100381610038161003816100381611987811 (119896)

1003816100381610038161003816

2)

minus119872(119896) 0) IMCmax)

(11)


11


11 and









0

02

04

06

08

1


CDF

of11119878


0 2 4 6 8 10 12 14 160

02

04

06

08

1

IMC (dB)

CDF

of IM

C









1 15 2 25 3 35 4 45 50

01

02

03

04

05

06

07

08

09

1

Perc

entil

e

Low EMIvalues

High EMIvalues





6 dB






















Beacon period (BP)

Time

Time

Time

Time

Awake Window

Station A

Station B

Station C

Station D


BPCn

t=0times

010

BPCn

t=0times

011

BPCn

t=0times

012

BPCn

t=0times

013

BPCn

t=0times

014


Preamble Carrier


Data Carrier









Payload

AV11delimiter

AV11delimiter

SD

PRSAV11

acknowledgement




RIFS CIFSRIFS

AV11delimiter



RIFS


RIFS




Preamble +FC + data

Preamble +FC + data











SOF SOF SACK















119867in Figure 23



119867











TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











Atte

nuat

ion

(dB)

times 107

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20


PSD

(dBm

Hz)


minus 160

minus 150

minus 140

minus 130

minus 120

minus 110

minus 100





0 10 20 30 40 50 60 70 80 90 100

0

Frequency (kHz)

Mag

nitu

de (d

B)



minus 100

minus 90

minus 80

minus 70

minus 60

minus 50

minus 40

minus 30

minus 20

minus 10

55 dB58 dB

27 dB42 dB 32 dB

13 dB






Copy and window

Copy and window



Flat guard

interval

FFT section


= 0 = RI

RIRI GI

TI2

TI2

TI2

TI2

I2

RI2

OFDM symbol


115 12 125 13 135 14

0

5

10

Frequency (MHz)

Pow

er (d

B)

10 carriers notch

543

2Singlecarriernotch

minus 30

minus 25

minus 20

minus 15

minus 10

minus 5

= 0= 001= 003125

= 00625= 0121








RI = 120573119879s (9)


119879119864= (1 + 120573) sdot 119879s (10)




















Frequency (Hz)

PSD

(dBm

Hz)


2 4 6 8 100times 107

A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 5 dB

SNR

=35

dB

(a)



times 107PS

D (d

BmH

z)A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 10 dBSNR

=30

dB

(b)







11987811


11 and






11
















(1

1 minus100381610038161003816100381611987811 (119896)

1003816100381610038161003816

2)

minus119872(119896) 0) IMCmax)

(11)


11


11 and









0

02

04

06

08

1


CDF

of11119878


0 2 4 6 8 10 12 14 160

02

04

06

08

1

IMC (dB)

CDF

of IM

C









1 15 2 25 3 35 4 45 50

01

02

03

04

05

06

07

08

09

1

Perc

entil

e

Low EMIvalues

High EMIvalues





6 dB






















Beacon period (BP)

Time

Time

Time

Time

Awake Window

Station A

Station B

Station C

Station D


BPCn

t=0times

010

BPCn

t=0times

011

BPCn

t=0times

012

BPCn

t=0times

013

BPCn

t=0times

014


Preamble Carrier


Data Carrier









Payload

AV11delimiter

AV11delimiter

SD

PRSAV11

acknowledgement




RIFS CIFSRIFS

AV11delimiter



RIFS


RIFS




Preamble +FC + data

Preamble +FC + data











SOF SOF SACK















119867in Figure 23



119867











TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










Copy and window

Copy and window



Flat guard

interval

FFT section


= 0 = RI

RIRI GI

TI2

TI2

TI2

TI2

I2

RI2

OFDM symbol


115 12 125 13 135 14

0

5

10

Frequency (MHz)

Pow

er (d

B)

10 carriers notch

543

2Singlecarriernotch

minus 30

minus 25

minus 20

minus 15

minus 10

minus 5

= 0= 001= 003125

= 00625= 0121








RI = 120573119879s (9)


119879119864= (1 + 120573) sdot 119879s (10)




















Frequency (Hz)

PSD

(dBm

Hz)


2 4 6 8 100times 107

A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 5 dB

SNR

=35

dB

(a)



times 107PS

D (d

BmH

z)A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 10 dBSNR

=30

dB

(b)







11987811


11 and






11
















(1

1 minus100381610038161003816100381611987811 (119896)

1003816100381610038161003816

2)

minus119872(119896) 0) IMCmax)

(11)


11


11 and









0

02

04

06

08

1


CDF

of11119878


0 2 4 6 8 10 12 14 160

02

04

06

08

1

IMC (dB)

CDF

of IM

C









1 15 2 25 3 35 4 45 50

01

02

03

04

05

06

07

08

09

1

Perc

entil

e

Low EMIvalues

High EMIvalues





6 dB






















Beacon period (BP)

Time

Time

Time

Time

Awake Window

Station A

Station B

Station C

Station D


BPCn

t=0times

010

BPCn

t=0times

011

BPCn

t=0times

012

BPCn

t=0times

013

BPCn

t=0times

014


Preamble Carrier


Data Carrier









Payload

AV11delimiter

AV11delimiter

SD

PRSAV11

acknowledgement




RIFS CIFSRIFS

AV11delimiter



RIFS


RIFS




Preamble +FC + data

Preamble +FC + data











SOF SOF SACK















119867in Figure 23



119867











TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation






















Frequency (Hz)

PSD

(dBm

Hz)


2 4 6 8 100times 107

A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 5 dB

SNR

=35

dB

(a)



times 107PS

D (d

BmH

z)A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 10 dBSNR

=30

dB

(b)







11987811


11 and






11
















(1

1 minus100381610038161003816100381611987811 (119896)

1003816100381610038161003816

2)

minus119872(119896) 0) IMCmax)

(11)


11


11 and









0

02

04

06

08

1


CDF

of11119878


0 2 4 6 8 10 12 14 160

02

04

06

08

1

IMC (dB)

CDF

of IM

C









1 15 2 25 3 35 4 45 50

01

02

03

04

05

06

07

08

09

1

Perc

entil

e

Low EMIvalues

High EMIvalues





6 dB






















Beacon period (BP)

Time

Time

Time

Time

Awake Window

Station A

Station B

Station C

Station D


BPCn

t=0times

010

BPCn

t=0times

011

BPCn

t=0times

012

BPCn

t=0times

013

BPCn

t=0times

014


Preamble Carrier


Data Carrier









Payload

AV11delimiter

AV11delimiter

SD

PRSAV11

acknowledgement




RIFS CIFSRIFS

AV11delimiter



RIFS


RIFS




Preamble +FC + data

Preamble +FC + data











SOF SOF SACK















119867in Figure 23



119867











TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










Frequency (Hz)

PSD

(dBm

Hz)


2 4 6 8 100times 107

A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 5 dB

SNR

=35

dB

(a)



times 107PS

D (d

BmH

z)A minus 100

A minus 90

A minus 80

A minus 70

A minus 60

A minus 50

A minus 40

A minus 30

A minus 20

A minus 10

A

SNR = 10 dBSNR

=30

dB

(b)







11987811


11 and






11
















(1

1 minus100381610038161003816100381611987811 (119896)

1003816100381610038161003816

2)

minus119872(119896) 0) IMCmax)

(11)


11


11 and









0

02

04

06

08

1


CDF

of11119878


0 2 4 6 8 10 12 14 160

02

04

06

08

1

IMC (dB)

CDF

of IM

C









1 15 2 25 3 35 4 45 50

01

02

03

04

05

06

07

08

09

1

Perc

entil

e

Low EMIvalues

High EMIvalues





6 dB






















Beacon period (BP)

Time

Time

Time

Time

Awake Window

Station A

Station B

Station C

Station D


BPCn

t=0times

010

BPCn

t=0times

011

BPCn

t=0times

012

BPCn

t=0times

013

BPCn

t=0times

014


Preamble Carrier


Data Carrier









Payload

AV11delimiter

AV11delimiter

SD

PRSAV11

acknowledgement




RIFS CIFSRIFS

AV11delimiter



RIFS


RIFS




Preamble +FC + data

Preamble +FC + data











SOF SOF SACK















119867in Figure 23



119867











TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation























(1

1 minus100381610038161003816100381611987811 (119896)

1003816100381610038161003816

2)

minus119872(119896) 0) IMCmax)

(11)


11


11 and









0

02

04

06

08

1


CDF

of11119878


0 2 4 6 8 10 12 14 160

02

04

06

08

1

IMC (dB)

CDF

of IM

C









1 15 2 25 3 35 4 45 50

01

02

03

04

05

06

07

08

09

1

Perc

entil

e

Low EMIvalues

High EMIvalues





6 dB






















Beacon period (BP)

Time

Time

Time

Time

Awake Window

Station A

Station B

Station C

Station D


BPCn

t=0times

010

BPCn

t=0times

011

BPCn

t=0times

012

BPCn

t=0times

013

BPCn

t=0times

014


Preamble Carrier


Data Carrier









Payload

AV11delimiter

AV11delimiter

SD

PRSAV11

acknowledgement




RIFS CIFSRIFS

AV11delimiter



RIFS


RIFS




Preamble +FC + data

Preamble +FC + data











SOF SOF SACK















119867in Figure 23



119867











TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










1 15 2 25 3 35 4 45 50

01

02

03

04

05

06

07

08

09

1

Perc

entil

e

Low EMIvalues

High EMIvalues





6 dB






















Beacon period (BP)

Time

Time

Time

Time

Awake Window

Station A

Station B

Station C

Station D


BPCn

t=0times

010

BPCn

t=0times

011

BPCn

t=0times

012

BPCn

t=0times

013

BPCn

t=0times

014


Preamble Carrier


Data Carrier









Payload

AV11delimiter

AV11delimiter

SD

PRSAV11

acknowledgement




RIFS CIFSRIFS

AV11delimiter



RIFS


RIFS




Preamble +FC + data

Preamble +FC + data











SOF SOF SACK















119867in Figure 23



119867











TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation




















Beacon period (BP)

Time

Time

Time

Time

Awake Window

Station A

Station B

Station C

Station D


BPCn

t=0times

010

BPCn

t=0times

011

BPCn

t=0times

012

BPCn

t=0times

013

BPCn

t=0times

014


Preamble Carrier


Data Carrier









Payload

AV11delimiter

AV11delimiter

SD

PRSAV11

acknowledgement




RIFS CIFSRIFS

AV11delimiter



RIFS


RIFS




Preamble +FC + data

Preamble +FC + data











SOF SOF SACK















119867in Figure 23



119867











TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











Payload

AV11delimiter

AV11delimiter

SD

PRSAV11

acknowledgement




RIFS CIFSRIFS

AV11delimiter



RIFS


RIFS




Preamble +FC + data

Preamble +FC + data











SOF SOF SACK















119867in Figure 23



119867











TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










SOF SOF SACK















119867in Figure 23



119867











TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










TDMU2TDMU1TMDU0

ACC IH-W IH-O IH-G

ISP window

TDMS7

TDMS6

TDMS5

TDMS4

TDMS3

TDMS2

TDMS1

TDMS0

TH


ISP119879


Timing Parameters


16 OFDM symbols

Time ( s)

minus 2times

le 1024









95 gt1365 gt220




99 gt1315 gt173












7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation

















7 Conclusion




References







































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation


























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









Documents

Research Article An Overview of the HomePlug AV2 Technologydownloads.hindawi.com/journals/jece/2013/892628.pdf · Research Article An Overview of the HomePlug AV2 Technology ... (TCC)