Doc.: IEEE 802.15-03/139r4 Submission July 2003 Didier Helal and Philippe Rouzet, STMSlide 1 Project: IEEE P802.15 Working Group for Wireless Personal

July 2003

Didier Helal and Philippe Rouzet, STMSlide 1

doc.: IEEE 802.15-03/139r4

Submission

Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

Submission Title: [STMicroelectronics proposal for IEEE 802.15.3a Alt PHY]Date Submitted: [14 July, 2003]Source: [Didier Helal (Primary) Philippe Rouzet (Secondary)] Company [STMicroelectronics]Address [STMicroelectronics, 39 Chemin du Champ des Filles 1228 Geneve Plan-les-Ouates, Switzerland]Voice [+41 22 929 58 72 or +41 22 929 58 66 ], Fax [+41 22 929 29 70], E-Mail :[[email protected], philippe [email protected]]

Re:

[This is a response to IEEE P802.15 Alternate PHY Call For Proposals dated 17 January 2003 under number IEEE P802.15-02/372r8 ]

Abstract: [This document contents the proposal submitted by ST for an IEEE P802.15 Alternate PHY based on UWB technique.]

Purpose: [Presentation to be made during July IEEE TG3a session in San Francisco, California]

Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.

July 2003


doc.: IEEE 802.15-03/139r4

Submission

July 2003, San Francisco, California

STMicroelectronics Proposal for

IEEE 802.15.3a Alternate PHY

Didier Hélal, Philippe Rouzet

R. Cattenoz, C. Cattaneo, L. Rouault, N. Rinaldi,

L. Blazevic, C. Devaucelle, L. Smaïni, S. Chaillou

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Contents

• Introduction to Pulse Position Modulation

• UWB PHY Proposal

• Performances results

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Pulse Position Modulation (1)

Time

PRP = Pulse Repetition Period = 1/PRF

A system with a PRF of 250MHz transmits 250 million pulses per second

Time

PRF = Pulse Repetition Frequency

A system with a PRF of 250MHz transmits one pulse every 4 nanosecond

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Pulse Position Modulation (2)

Time

A system with a PRF of 250MHz using a 4-PPM transmits 500 million bits per second

Position 1

Time

A system with a PRF of 250MHz using a 4-PPM + Polarity transmits 750 million bits

per second

Position 2Position 3Position 4

July 2003


doc.: IEEE 802.15-03/139r4

Submission

1 2

Tp = 300ps

1 bit / pulse

2 bits / pulse

3 bits / pulse

t

3 4Equally spaced Positions

Polarity

2-PPM +

Polarity

4-PPM +

Polarity

July 2003


doc.: IEEE 802.15-03/139r4

Submission

BIT MAPPING

• Gray-invert mapping: takes advantage from the bi-orthogonal modulation PPM+Polarity.

000 001 011 010

101100110111

PPMerror

antipodalerror PP

July 2003


doc.: IEEE 802.15-03/139r4

Submission

MODULATION

PAYLOAD Bit Rate Target

PAYLOAD Bit Rate Effective

Modulation Code-rate

PRP

55 Mbps 62.5 Mbps BPSK 1/2 8 ns

110 Mbps 125 Mbps BPSK +

2-PPM

1/2 8 ns

200 Mbps 250 Mbps BPSK +

4-PPM

2/3 8 ns

480 Mbps 500 Mbps BPSK + 4PPM

2/3 4 ns

July 2003


doc.: IEEE 802.15-03/139r4

Submission

PPM Modulation capacity

• Increasing the number of pulse positions brings better efficiency

-2 0 2 4 6 8 10 120

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Eb/No (dB)

Cap

acity

/Max

imum

ach

eiva

ble

capa

city

2-PPM 4-PPM 8-PPM16-PPM32-PPM

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Channel coding options (1)

• Convolutional code

– Code rate ½, constraint length K=7, [133,171]:

– Puncture table for code rate = 2/3: [1 1 0 1 1 1 1 0]

z-1InputData

Coded bit 1

Coded bit 2

z-1 z-1 z-1 z-1 z-1

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Channel coding options (2)

• Turbo codes PCCC (Parallel Concatenation of Convolutional Codes)

– Code rate 1/3. With puncturing:1/2, 2/3,7/8.

– RSC (recursive systematic convolutional) 13,15(octal def.).

– Block size: 512.

– Low latency : 5 s

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Adaptive band Pulse shape

• Pulse shape should be adapted to any regulation, provided the pulse power spectral density fits emission mask.

• Flexibility on pulse shape enables compatibility with more stringent regulations worldwide.

• See ref. IEEE 802.15-03/211r0.

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Backward and Forward compatibility

• First generation systems will use the lower part of the band due to technology limitations, e.g. 3-7GHz

• Next generation will extend this bandwidth e.g. to 3-10GHz, older systems using the energy in 3-7GHz band.

3 4 5 76 98 10 11

Frequency (GHz)

UNII

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Example of a full band pulse shape

BW-10dB = 7.26 GHzAverage TX power = 0.3 mW

Peak emission power in 50MHz = -10 dBm

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Example of a low band pulse shape

BW-10dB = 4 GHzAverage TX power = TBD mW

Peak emission power in 50MHz = TBD dBm

July 2003


doc.: IEEE 802.15-03/139r4

Submission

FRAME: Known Training Sequencefor Frame Synchronization and Channel Estimation

Example of a simplified emitted pulse train

Pulse shape not shown (use rectangle for clarity)

Preamble Modulated user data

Time Hopping + Polarity

2-PPM + Polarity (Time Hopping optional)

PRP

Frame

Frame Preamble

July 2003


doc.: IEEE 802.15-03/139r4

Submission

BEACON is a regular frame with appended preamble for Coarse Synchronization

Piconet Information


2-PPM + Polarity (Time Hopping optional)

PRP


Coarse Sync. Frame Sync.+ Ch. Est

Beacon

Beacon Preamble

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Cell synchronization (1)

PNC

DEV-A

DEV-B

Scenario

Cell s

ynch Cell synch

Dev-dev synch

A device which enters the piconet has to

1) Detect the piconet code

2) Find approximate beginning of beacon data

3) Estimate its clock drift with PNC

4) Channel estimation and fine synchronization to allow best energy capture

5) Compensate for residual clock drift

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Cell synchronization (2)1. Coarse synchronization

1.1 Detection of the piconet code among 20 possible.

1.2 Alignment: find the end of the superframe beacon preamble. Goal is also to find the beginning of the channel impulse response. This is done by detecting the first path above a fixed threshold. May lead to some uncertainties (thus operation is called ‘coarse’).

2. Coarse clock drift correction, based on information given in 1.2. Is made based on several superframe beacon preambles. Use of basic interpolation or adaptive filtering (like Kalman, should the oscillator spec require it) to predict clock drift.

3. Fine synchronization: can take place now, with better accuracy, since some of the clock drift between PNC and DEV has been removed in 2. Via channel estimation and processing, can align to the beginning of the channel impulse response with much more accuracy than after 1.2.

4. Fine clock drift correction, based on information given in 3.

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Coarse Synchronization (1)

Preamble coding :

TIME HOPPING + POLARITY

Preamble codes :

Sequences of length Lc = 79

TH = Quadratic-Congruence (QC) sequences

Cn = time-hopping offset (multiple of time-hopping resolution)

POL = Derived from row of a Hadamard matrix of size 80 x 80

79mod)*( 2)( nic in • i = 1,2,…,78: sequence number

• n = 0,1,…,78: TH offset index

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Coarse Synchronisation (2)

• Preamble construction•PRP = 8 ns. TH offset resolution: 50ps.

•Sequence is repeated R = 120 + 3 times.

•Duration of coarse sync beacon preamble: DC = R*LC *PRP = 77.7 s.

…..

120 repetitions

End of Beacon Preamble (EOBP) signature

Beacon preamble duration: DC = 77.7 s

One sequence: LC*PRP

+

--

++

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Coarse Synchronisation (3)

Contention Free Period

MC

TA

1

CT

A

1

MC

TA

n

C

TA

2

CT

A

m

pre

amb

le

hea

der

bo

dy

Beacon

CT

A

x

Contention

Access

Period

Superframe N

pre

amb

le

Detection : Find one sequence among 20

Alignement : Find end of coarse synchronization beacon preamble with a precision of ~10 ns.

Superframe N+1

… … … …

pre

amb

le

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Coarse Clock Synchronization (1)


MC

TA

1

CT

A

1

MC

TA

n

C

TA

2

CT

A

m

pre

amb

le

hea

der

bo

dy

Beacon

CT

A

x

Contention

Access

Period

Superframe N

pre

amb

le

Superframe N+1

… … … …

pre

amb

le

correct clock drift between TX DEV and RX DEV

pre

amb

le

TSF: average superframe period (e.g. 10 ms)

slope of clock drift = ((ti+1 – ti) – TSF)/TSF

ti+1 ti

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Coarse Clock Synchronization (2)

Coarse Drift estimation and tracking

• Clock tracking algorithm uses coarse synchronization ouptuts to predict clock drift over next superframe, by basic interpolation or implementing an adaptive filter (like Kalman, should the oscillator spec require it).

• Drift correction down to ~1 ppm. Enough for fine synchronization & channel estimation, done over 6 s.

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Fine Synchronization


MC

TA

1

CT

A

1

MC

TA

n

C

TA

2

CT

A

m

pre

amb

le

hea

der

bo

dy

Beacon

CT

A

x

Contention

Access

Period

Superframe N

pre

amb

le

Superframe N+1

… … … …

pre

amb

le

DEV-A synchronized to PNC’s clock

DEV-A demodulates beacon Fine Synchronisation is made jointly with channel

estimation and optimizes energy capture

Fine synchronization algorithm gives end of beacon preamble (blue) with good accuracy

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Fine Clock Synchronization

Fine clock drift estimation and tracking

• Clock tracking algorithm uses fine synchronization ouptuts to refine clock drift prediction down to 0.1ppm. Enough for demodulation over 100 s


MC

TA

1

CT

A

1

MC

TA

n

C

TA

2

CT

A

m

pre

amb

le

hea

der

bo

dy

Beacon

CT

A

x

Contention

Access

Period

Superframe N

pre

amb

le

Superframe N+1

… … … …

pre

amb

le

pre

amb

le

July 2003


doc.: IEEE 802.15-03/139r4

Submission

DEV-to-DEV Synchronization (1)


MC

TA

1

CT

A

1

MC

TA

n

C

TA

2

CT

A

m

pre

amb

le

hea

der

bo

dy

Beacon

CT

A

x

Contention

Access

Period

Superframe N

Body

Frame sent to DEV-A by DEV-B

Hea

de

r

Pre

am

ble

pre

amb

le

Superframe N+1

… … … …

pre

amb

le

DEV-A wakes up, and needs to synchronize to DEV-B’s clock.

DEV-A’s clock is synchronized to DEV-B’s clock, and can start to demodulate the data contained in the frame sent by DEV-B.

1) Clock drift is known and can be corrected

2) Fine Synchronisation and channel estimation

3) Demodulation

July 2003


doc.: IEEE 802.15-03/139r4

Submission

DEV-to-DEV Synchronization (2)

f1 and f2 are estimated during cell synchronization phase, by DEV-1 and DEV-2 respectively

f12 is known by PNC and must be corrected by DEVs

PNC

DEV-1TX

DEV-2RX

f1f2

f12

July 2003


doc.: IEEE 802.15-03/139r4

Submission

DEV-to-DEV Synchronization (2)Two solutions

1. RX DEV corrects for both f1 and f2.

+ Better precision

- MAC needs to provide f values to all piconet devices.

2. TX DEV correct f1 by adjusting pulse position transmission

+ RX DEV does not need to know f1

- Less precise

July 2003


doc.: IEEE 802.15-03/139r4

Submission

PHY-SAP Data Throughput close to Payload Bit Rate

PHY Header, MAC Header (802.15.3 format), HCS use 62.5Mb/s mode

Optimized Packet Overhead Times

Payload Bit Rate (Mb/s)

PHY-SAP Throughput (Mb/s) 5 frames

PHY-SAP Throughput (Mb/s) 1 frame

T_DATA

(1020 Bytes MPDU)

62.5(mandatory) 58.26 56.9 132.68 s

125 (mandatory) 109.49 106.27 66.34 s

250 (optional) 195.4 188.25 33.04 s

500 (optional) 321.56 301.8 16.79 s

T_PA_

INITIAL

T_PHYHDR

T_MACHDR

T_HCS T_MIFS T_SIFS T_PA_

CONT

T_RIFS

6 s 0.26s 1.3 s 0.26s 1s 2 s 6 s 4 s

July 2003


doc.: IEEE 802.15-03/139r4

Submission

MAC enhancements

Proposed MAC is compliant with existing MAC IEEE 802.15.3

• Introduction of optional minor MAC adaptations to optimize– Receiver power consumption– Complexity (synchronization)– Performance (ARQ)

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Frame reception (1)• Approximate frames Times Of Arrival (TOAs) used

in CTA slots

TOA information announced by source DEV at the begining of CTA

– Used for channel estimation & synchronization

– Several ways of TOA signaling possible (i.e. one example presented after)

– Benefits :

• ARQ scheme can be improved (One ACK per CTA to lower overhead)

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Proposed TOA used by MAC for Frame synchronization

•Use of approximate frame TOAs to manage different lengths of frames and facilitate frame synchronization

CTA slot in superframe

Frame 1 MIF

SFrame 2 M

IFS

MIF

S

MIF

S

3 Frame 4 Frame 5

MIF

S

6

MIF

S

TO

A 1

TO

A 2

TO

A 3

TO

A 4

TO

A 5

TO

A 6

TOA 1 TOA 2 TOA 3 TOA 4 TOA 5 TOA 6

MIF

S

CTA Header announcing TOAs

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Frame reception (2)

• Randomized access without CAP

Use MCTA slots and Slotted Aloha instead of CAPVERY LOW POWER CONSUMPTION

• Randomized access within CAP without CSMA/CA

Use CAP with a new Slotted mechanismLOW POWER CONSUMPTION

• Randomized access within CAP with CSMA/CA

Use CAP as defined in 802.15.3: CSMA/CA with CCA

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Randomize access within CAP• CSMA/CA in CAP is possible by CCA through preamble

detection but not efficient– CCA consumes a lot of energy (due to UWB environment, true for

all PHY layer proposals and not only STM one)– Not suitable for time-bounded consumer applications (audio/video

streaming)

• Better solution is to do CCA by Slotted CAP mechanism

20ns 20ns 20ns 20ns 20ns

10μs 10μs 10μs 10μs

…

CAP

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Proposed Alternate PHY enables

Single Chip FULL CMOS solution

Through

DIRECT SAMPLING on 1 BITand

DIGITAL MATCHED FILTERINGLearn pulse signature after channel propagation

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Demodulation is performed by Match-Filtering

The match-filter is the estimate of the pulse signature through channel propagation

No pulse shape is assumed by receiver !

Take advantage of multi-path (complete immunity)

Match-filtering

Compound Channel Response

Average

Demodulation

Channel Estimation

Tx signalRx signal

Channel+ Noise

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Channel estimation chain• Picture shows E/No = 6dB• Time window is 50ns and 1ns 1 bit ADC

Noise injection

Average of 750 pulses (1-bit

sampled)

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Channel estimation

• The channel estimated is compared with the actual channel response

• Averaging 1 bit data remove noise and gets accurate estimation

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Channel estimation easy to implement• Each point of the channel estimation can be seen as one finger of a rake

receiver64 ns = 1280 fingers of 50 ps width

• Channel estimation consists in coherent integration of received pulses.

One bit ADC makes the operation a simple increment/decrementNo multiplication or complex operator !

• Estimated gate count of the whole channel estimation block

bit slice number of gates * number of bit of the counter * number of channel point(20*7*1280 = 179200 gates)

• Power consumption

Parallel hardware implementation of all fingersFrequency of operations is low (1/PRP)

July 2003


doc.: IEEE 802.15-03/139r4

Submission

RF block

Antenna

BPFilter

Pulse

Generator

Clock

Synthesizer

1-bit

ADC

TDD

Switch

ABR

ABR

Optional

LNA

PTC

UWB System-on-ChipBlock Diagram

Channel estimation

Synchronization

DemodulationChannel

Decoding

Channel

Coding

Modulation &

coding

Baseband block

TX

Data

RX

Data

TX

Preparation

Frag-mentation

TX

Control

RX

Control

Defrag-

mentation

MAC block (Bottom part)

PTC

ABR = Adaptive Band RejectionPTC = Piconet Time Control

MAC+BB+RF on same silicon except BP filter and Antenna

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Link Budget

Noise figure for all RX chain referred at the antenna output

Implementation loss = jitter effect <2dB (varies with pulse shape) + 2dB margin in order to enable simplest demodulation

Antenna

BPFilter

Pulse

Generator

Clock

Synthesizer

1-bit

ADC

TDDSwitch

ABR

ABR

Optional

LNA

2dBloss

0.5dBloss

NF = 3dB2dB

G = 16dB

NF = 9dB

Clock Jitter : 10ps rms (maximum from 0.13m silicon measurements)

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Performances Summary

• The following results are voluntary based on- 3-7GHz pulse instead of 3-10GHz- Convolutional coding instead of Turbo Coding

July 2003


doc.: IEEE 802.15-03/139r4

Submission

110Mbps @ 10m, AWGNThroughput Rb (Mb/s) 125Distance (m) 10.0Average TX power Pt (dBm) -5.58Tx antenna gain Gt (dBi) 0.0Fc (Hz) 4.9E+09Path loss 1 meter L1 (dB) 46.2Path loss at d meter L2 (dB) 20.0Rx antenna gain Gr (dBi) 0.0Rx power Pr (dBm) -71.7N = -174 + 10*LOG10(Rb) (dBm) -93.0Noise Figure (dB) 6.1Average noise power per bit Pn (dBm) -86.9Eb/No min (dB) TBDImplementation Loss (dB) 4.0Link Margin (dB) #######Proposed Min Rx sensitivity Level (dBm) #######

MAXIMUM RANGE

TBD m

EFFECTIVE THROUGHPUT

125 Mbps

RESULTS INCLUDE SHADOWING

July 2003


doc.: IEEE 802.15-03/139r4

Submission

200Mbps @ 4m, AWGN

MAXIMUM RANGE

TBD m


250 Mbps

Throughput Rb (Mb/s) 250Distance (m) 4.0Average TX power Pt (dBm) -5.58Tx antenna gain Gt (dBi) 0.0Fc (Hz) 4.9E+09Path loss 1 meter L1 (dB) 46.2Path loss at d meter L2 (dB) 12.0Rx antenna gain Gr (dBi) 0.0Rx power Pr (dBm) -63.8N = -174 + 10*LOG10(Rb) (dBm) -90.0Noise Figure (dB) 7.0Average noise power per bit Pn (dBm) -83.0Eb/No min (dB) TBDImplementation Loss (dB) 4.0Link Margin (dB) #######Proposed Min Rx sensitivity Level (dBm) #######


July 2003


doc.: IEEE 802.15-03/139r4

Submission

480Mbps @ 1m , AWGN

MAXIMUM RANGE

TBD m


500 Mbps

Throughput Rb (Mb/s) 500Distance (m) 1.0Average TX power Pt (dBm) -5.58Tx antenna gain Gt (dBi) 0.0Fc (Hz) 4.9E+09Path loss 1 meter L1 (dB) 46.2Path loss at d meter L2 (dB) 0.0Rx antenna gain Gr (dBi) 0.0Rx power Pr (dBm) -51.7N = -174 + 10*LOG10(Rb) (dBm) -87.0Noise Figure (dB) 6.1Average noise power per bit Pn (dBm) -80.9Eb/No min (dB) TBDImplementation Loss (dB) 4.0Link Margin (dB) #######Proposed Min Rx sensitivity Level (dBm) #######


July 2003


doc.: IEEE 802.15-03/139r4

Submission

55Mbps @ 10m, AWGNThroughput Rb (Mb/s) 62.5Distance (m) 10.0Average TX power Pt (dBm) -5.58Tx antenna gain Gt (dBi) 0.0Fc (Hz) 4.9E+09Path loss 1 meter L1 (dB) 46.2Path loss at d meter L2 (dB) 20.0Rx antenna gain Gr (dBi) 0.0Rx power Pr (dBm) -71.7N = -174 + 10*LOG10(Rb) (dBm) -96.0Noise Figure (dB) 6.1Average noise power per bit Pn (dBm) -89.9Eb/No min (dB) TBDImplementation Loss (dB) 4.0Link Margin (dB) #######Proposed Min Rx sensitivity Level (dBm) #######

MAXIMUM RANGE

TBD m


62.5 Mbps


July 2003


doc.: IEEE 802.15-03/139r4

Submission

Coding Performances in CM4 channelcoding PRP #PPM Code rate Data rate # operations Eb/No

TC - RSC [13,15] 8ns 4 1/3 125Mbps equivalent dB

CC - [133,171] 8ns 2 1/2 125Mbps equivalent dB

For similar complexity

Using a convolutionnal coding

instead of a Turbo coding results in a

1.4dB loss in performances

July 2003


doc.: IEEE 802.15-03/139r4

Submission

• Coexistence with in-band systems ensured by TX pulse shaping or filtering

– System is independent from pulse shape

• Transmit power control reduces interferences

– Helped by location awareness capability (distance can be estimated with 3cm resolution)

• No impact on current regulation

– FCC’s Part 15 rules followed

– Additional spectrum protection

can be supported

• 802.15.3 Power Management modes are supported

(DSPS, PSPS, APS)

Coexistence and regulatory impact

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Simultaneously operating PiconetsSingle Interferer

TX DEV

RX DEV

Interferer

dint

CM1, CM2, CM3 or CM4multipath channel

dref

CM1, CM2, CM3 or CM4

multipath channel

Rx level = (limit PER=8%) + 6dB

Modulation : 2-PPM, Prp = 8 ns,CR 1/2, 125 MbpsContinuous overlapping interferer transmission (worst condition)

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Simultaneously operating PiconetsSingle piconet interferer

• Dref/Dint is better than TBD (for 125 Mbps modulation)– CM3, CM4 supports interferer @ ~TBD meters for a Ref source

@ 10 meters– Interfering channel slightly impacts performance (better for low

density channel such as CM1 and CM2, instead of CM3,CM4) -> meters instead of meters

– Pulse BW impact performances Dref/Dint ~ (BW)– PRP or Datarate impact performances Dref/Dint ~ (PRP) using the

same modulation scheme, just changing PRP (and along the datarate)• Gracefull degradation of performance in case of strong UWB

interferer by adjusting PRP

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Simultaneously operating PiconetsEffect of TH

• Effect of Time hopping in modulated data on interferer immunity– Small effect, equivalent of ~0.1 dB

– Effect is marginal on average but smooth some worst case

• Marginal improvement for a marginal added complexity– TH may be kept as on option in standard (TBD)

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Simultaneously operating PiconetsMultiple Piconet interferers

TX DEV

RX DEV

dint

CM3 or CM4multipath channel

dref

Free space channel

Rx level = (limit PER=8%) + 6dB

3 Interferers

Modulation : 2-PPM, Prp =8 ns,CR 1/2, 125 MbpsContinuous overlapping interferer transmission (worst condition)

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Simultaneously operating PiconetsMultiple piconet interferer

• Multiple Interferer use free space channel

– Low width of pulse means small effect on receiver

– Infinite rake architecture and 1 bit sampling gives strong performance here

• 2 Interferers : Dref/Dint is better than TBD (for 125 Mbps modulation)

– CM1, CM2, CM3, CM4 supports 2 interferers @ ~TBD meters for a Ref source @ 10 meters

• 3 Interferers : Dref/Dint is better than TBD (for 125 Mbps modulation)

– CM3, CM4 supports 3 interferers @ ~TBD meters for a Ref source @ 10 meters

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Simultaneously operating PiconetsMultiple piconet interferer

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Interference and Susceptibility

• Performances in a simple configuration : fixed UNII notch filter that can be bypassed.

• All out-of-band interferers supported (according to IEEE 802.15-3a proposed criteria).

July 2003


doc.: IEEE 802.15-03/139r4

Submission

PAYLOAD Bit Rate Target

PAYLOAD Bit Rate Effective

Modulation Code-rate PRP Power Consumption

55 Mbps 62.5 Mbps Pol 1/2 8 ns TBD mW

110 Mbps 125 Mbps Pol+2ppm 1/2 8 ns TBD mW



Power Consumption estimates

Hypothesis : convolutional coding, channel estimation operating during 10% of time

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Gate count & Consumption calcul (1/2)Example with the Channel Estimation

• Each point of the channel estimation can be seen as one finger of a rake receiver.(I.e. 64 ns = 1280 fingers of 50 ps width)

• The channel estimation consists to integrate coherently pulses. As the front-end is a one bit ADC, for each point of the channel, the operation is simply an increment/decrement.(I.e 1280 Inc/Dec for each pulse in TS, 1000 pulses -> 1.2 M Inc/Dec, No multiplication or complex operator !)

• Estimated gate count : – We need about 20 gates for each bit slice of an up-down counter : on flip-flop, and add-

sub and a few more for count gating.– So the gate count of the whole channel estimation block is : 20 * number of bit of the

counter * number of point of the channel(Using parallel hardware implementation of each finger, to keep low clock rate of 1/PRP)

• Consumption : – As the increment/decrement operation needs to be done only at each pulse the frequency

is 1/PRP.– The estimation of the consumption in 0.13 m is 6 nW/Gate/MHz

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Gate count & Consumption calcul (2/2)Data Rate (Convolutional Code)Channel Length (ns) 1

Number of Coherent Integration 2

PPM Number 3

Minimum PRP (ns) 4

Bit Rate (Mbits/sec)

Area/Gates Consumption Area/Gates Consumption

RF Transmitter (mm 2 - mW) 1.5 40 1.5 40Digital Transmitter (gates - mW) 20000 15 20000 15

Total Transmitter (mm2 - mW) 1.6 55 1.6 55

RF Receiver (mm 2 - mW) 1.5 70 1.5 70Digital RX Time Hopping Processing (gates - mW) 17920 13.44 17920 13.44Digital RX Channel Estimation (gates - mW) 174080 130.56 174080 130.56Digital RX Demodulation (gates - mW) 35840 26.88 71680 53.76Digital RX Channel Decoding (gates - mW) 50000 37.5 50000 37.5

Total Receiver 5 (mm2 - mW) 2.9 158.2 3.1 182.4

5 : The total consumption supposed that the channel estimation is in operation during 10% of active time and the demodulation and channel decoding 90% of active time

1 : The Channel Length parameter correspond to the windows on which the channel estimation and demodulation is performed.2 : NCI is the number of coherent integration done for the demodulation.3 : PPM number is the number of position for the pulse modulation. There is as many metric block as PPM4 : The minimum PRP (Pulse Repeating Period) indicate directly the max frequency of the chip.

8 8250 375

128 128

2 4

125 Mbits/sec 250 Mbits/sec64 64

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Power saving optimization

• Simulations show that doing a channel estimation on 30 ns for CM1 and CM2 is sufficient (ie. no impact on performance). For a 4 PPM system, the consumption of the baseband part would then be of 72 mW instead of 112 mW.

• For CM3 and CM4, simulations shows that 50 ns is sufficient. For a 4 PPM system, the consumption would be 90mW instead of 112 mW.

• Note that having a channel of 64 ns allows to shorten the synchronization time.

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Very Low Cost Architecture : Sampling at 14 GHz

• In our presentation we use a one bit sampler at 20 GHz. But it still possible to use a one bit sampling at a lower frequency : simulations using a sampler at 14 GHz shows a loss on performances of only 0.5 dB

• On the baseband part (without the channel decoding) this allows to reduce the size and the power consumption : with 4 PPM, we have 0.9 mm2 and 53.5 mW instead of 1.3 mm2 and 75 mW.

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Choice of sampling RATE

• Sampling frequency is defined by implementer– 20 GHz for top

performance– 14 GHz for low end

product (0.5 dB loss from 20 GHz for 3-7 GHz pulse, simulation done with CM1 channel, at 125 Mbps datarate)

– Lower sample frequency possible but larger loss (undersampling of pulse bandwidth)

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Current Demonstrator Platform

• RF transmitter and receiver : ASIC. – First chipset already in test– Full chipset on September 2003

• Baseband – Today : off-the-shelves board (Nallatech BenNuey) with FPGA

Xilinx Virtex2 6000– End of 2003 : ASIC 0.13 m

• Current progress in demonstrator shows low risk manufacturability (Baseband in FPGA today implies easy migration to ASIC, RF already in test)

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Lay-out of the clock generation block

CMOS 0.13m

July 2003


doc.: IEEE 802.15-03/139r4

Submission

FPGA Floorplaning and Routing

Current estimates on gate count

and power consumption are

based on real implementation

Design Information------------------Target Device : x2v6000Target Package : bf957Target Speed : -4Mapper Version : virtex2 -- $Revision: 1.4 $Mapped Date : Fri May 09 11:15:23 2003

Design Summary-------------- Number of errors: 0 Number of warnings: 0

Number of Slices: 25,606 out of 33,792 75% Number of Slices containing unrelated logic: 0 out of 25,606 0% Number of Slice Flip Flops: 6,298 out of 67,584 9% Total Number 4 input LUTs: 36,944 out of 67,584 54% Number used as LUTs: 33,305 Number used as a route-thru: 3,639 Number of bonded IOBs: 93 out of 684 13% IOB Flip Flops: 67 Number of GCLKs: 1 out of 16 6%

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Easy Manufacturability and attractive form factor

• Full system can be built in CMOS technology– single chip– Die size estimated at less than 5mm2 in 0.13m

• Antenna size : expected 3cm x 3cm (printed PCB)

• Time to Market can be less than 1.5 years !

July 2003


doc.: IEEE 802.15-03/139r4

Submission

CRITERIA REF LEVEL STM RESPONSE

General Solution Criteria

Unit Manufacturing Complexity 3.1 B + Low - Single chip solution

Signal Robustness

Interference and Susceptibility 3.2.2 A + Out-band and In-band Interferers

rejected at down to TBD m

Coexistence 3.2.3 A + Pulse shaping or filtering

Technical Feasibility

Manufacturability 3.3.1 A + Easy - full CMOS

Time To Market 3.3.2 A + 1.5 year

Regulatory Impact 3.3.3 A + Flexible emitted pulse shape

Scalability 3.4 C + Scalable data rates, ranges and

power consumption

Location awareness 3.5 C + Supported + built in “hooks”

MAC Protocol Enhancement Criteria

MAC Enhancements And Modifications 4.1 C + Compliant

July 2003


doc.: IEEE 802.15-03/139r4

Submission

CRITERIA REF. LEVEL STM RESPONSE

PHY Protocol Criteria

Size And Form Factor 5.1 B + Single Chip 5mm2

PHY-SAP Payload Bit Rate & Data Throughput

Payload Bit Rate 5.2.1 A + All rates supported up to 0.5Gbps (+Low Data Rates)

PHY-SAP Data Throughput 5.2.2 A + Short preamble and inter-frame space

Simultaneously Operating Piconets 5.3 A + Different preambles for piconets

TH+polarity code division

Signal Acquisition 5.4 A + Short synchronization time

(good sequence/continuous sampling)

Link Budget 5.5 A + Margin is TBD dB at 10m (2dB for lowest complexity)

Sensitivity 5.6 A + TBDdBm (TBD dBm for lowest complexity) @110Mbps

+ TBDdBm (TBDdBm for lowest complexity) @55Mbps

Multi-Path Immunity 5.7 A + Channel Estimation + Matched-Filter

Retrieves all energy

Power Management Modes 5.8 B + All modes supported

Power Consumption 5.9 A + Very Low. ADC already scaled for highest data-rates

Antenna Practically 5.10 B + 3cmx3cm printed

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Proposal matches all criteria

at

Very Low Cost

and

Very Low Power Consumption

Thank you for your attention

Questions are welcome…

July 2003


doc.: IEEE 802.15-03/139r4

Submission

BACKUP SLIDES

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Monopulse Adaptive band PPM assets• Theoretical capacity is linear with BW• Per bit energy maximized (for a given datarate and

spectrum limit) • Simultaneously operating piconets supported

UWB interference rejection varies along with BW.PRP product

Given a modulation scheme, dref/dint ~ sqrt(BW)

• Synchronizationuse of full BW, good energy level available, short sequence possible, fine synch and channel estimation optimized joint process

• Good localization ability thanks to better channel time resolution

• Less fading issues, optimal energy capture (using infinite rake architecture)

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Monopulse Adaptive band assets

• Pulse shape (so BW) is not hard coded in standard

• Backward compatibility between technology generationsE.g. 3.1-7GHz in 0.13um and 3.1-10.6GHz in 90nm

• Flexible data rate : PRP is easily changed

• Compatibility between High and Low Data Rate devices

• Complexity decreases along with data rate

• Power consumption decreases with data rate

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Simultaneously operating PiconetsSingle piconet interferer : Hypothesis

• Simulation hypothesis– Reference link is a multipath channel in CM3 or CM4 (CM1 and CM2 are

short range and “easy case”, no near far, so not considered for first simulations), several (5) channels of each CM are used

– Rx level is tuned to get 6 dB above the limit of 8% PER (limit level is known from performance simulation as Eb/No for the current simulated channel, 200+ packets simulated to get the reference)

– Interferer level is set from dint simulated (P.d² is constant, and Tx power is same for Ref and for interferer)

– Interferer channel is a multipath channel in CM1,2,3 or 4 (5 channels of each are used)

– Modulation used is 2-PPM, Prp =8 ns, CR 1/2, 125 Mbps

– Simulation operation : dint is tuned to get the reference PER limit of 8% (only the WORST case ratio of distance : dref /dint is kept as result)

July 2003


doc.: IEEE 802.15-03/139r4

Submission


• Simulation results P1(3-10GHz) at Eb/No ~ dBWorst case ratio

Dref/dint

(= Near far factor)

Int is CM1 Int is CM2 Int is CM3 Int is CM4

Ref is CM1

(5 channels used)

Ref is CM2

(5 channels used)

Ref is CM3

(5 channels used)

Ref is CM4

(5 channels used)

July 2003


doc.: IEEE 802.15-03/139r4

Submission


• Simulation results P2 (3-7GHz) at Eb/No ~ dBWorst case ratio

Dref/dint

(= Near far factor)

Int is CM1 Int is CM2 Int is CM3 Int is CM4

Ref is CM1

Ref is CM2

Ref is CM3

(5 channels used)

Ref is CM4

(5 channels used)

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Simultaneously operating PiconetsMultiple piconet interferers

• Simulation hypothesis– Reference link is a multipath channel in CM3 or CM4 (CM1 and CM2 are

short range and “easy case”, no near far, so not considered for first simulations), several (5) channels of each CM are used

– Rx level is tuned to get 6 dB above the limit of 8% PER (limit level is known from performance simulation as Eb/No for the current simulated channel, 200+ packets simulated to get the reference)

– Interferer level is set from dint simulated (P.d² is constant, and Tx power is same for Ref and for interferer)

– 2 or 3 independent UWB source interferers– Interferer channel is a free space channel– Modulation used is 2-PPM, Prp =8 ns, CR 1/2, 125 Mbps

– Simulation operation : dint is tuned to get the reference PER limit of 8% (only the WORST case ratio of distance : dref /dint is kept as result)

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Channel Estimation Algorithm

• The channel response is estimated with the training sequence

• Coherent integrations (on the received pulses) reduces noise and ISI effects.

• Most of channel energy is recovered by so.

• SNR at RX is good enough to reduce PRP and to increase data rate.

• System is independent from transmitted pulse shape – No need for Pulse Template

July 2003


doc.: IEEE 802.15-03/139r4

Submission

NPPM Correlations

APP calculations

N-PPM (number of Pulse positions) soft values corresponding to each PPM position at Pulse Repetition Frequency.

Channel estimation

RF DeinterleavingBL=BTC/C

depuncturechannel decoder

(Turbo decoder or Viterbi decoder)

channel decoding architecture

descrambling

Uncorrelates bit errors at the input of the decoder :C=code rateBTC=Turbo code block length.

Adds scalability

demapping and soft A priori per bit Probability calculations.

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Turbo code

• Latency is mainly due to the storage of one block into the channel de-interleaver.

@110Mbps: 512/110e6~5us.@ 55Mbps: 512/55e6=10us.

• Complexity: – RAM: 50 000 bits.– ~500 kGates

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Performance Indicators

• False Alarm probability (PFA): a preamble is detected where there is none

A target PFA ~ 10-4 is assumed

• Missed Detection probability (PMD): the preamble is not detected

A target PMD ~ 10-4 is assumed

• Beacon training sequence length ~ overhead percentage ~ synchronization time

Hypotheses

• No clock jitter present

• No clock drift present

• Send at max power allowed by FCC

• PRP = 10.8 ns

• Superframe ~= 10 ms

• CM3 channels utilised

• Most proposed pulse shapes will do

• Dimension preamble sequence for worst conditions: 110 Mbps @ 10m

Coarse synchronization

July 2003


doc.: IEEE 802.15-03/139r4

Submission

• First step: Preamble Detection

- Goal: search sequentially one sequence among 20 possible.

- Done over the first 120 repetitions of the QCH sequence.

- If piconet present and SNR >~ -7dB: Integration over 3 repetitions of the QCH sequence is enough. Sequence will be detected within 10 ms (at most 2 superframe beacons necessary).

- If piconet present but bad radio conditions: need to combine 4 or more QCH sequences to achieve detection.

• Second step: Alignment

- Goal: find end of beacon preamble.

- Done with aid of EOBP signature. Try to correlate with last 5 replicas of the beacon preamble: [+1 +1 –1 –1 +1].

Coarse Sync: Timeline

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Coarse sync: pulse comparison

SNR [dB]

PRP = 5.4 ns, L = 237, THR = 111 CM3

-10 -9.5 -9 -8.5 -8 -7.5 -7 -6.5 -6 -5.5 -5

10-4

10-3

10-2

10-1

100

10-5

PM

D

P3.1-10.6, no jitterP3.1-10.6, 10ps jitterP3.1-7, no jitterP3.1-7, 10ps jitter

P3.1-7 - 45, 10ps jitterP3.1-5, no jitterP3.1-5, 10ps jitter

P3.1-7 - 45, no jitter

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Channel estimation Simulation Results

• Loss due to reduction of training sequence length from 6s to 3s equals 1dB

0 2 4 6 8 10

10-2

10-1

Eb/No

Ser

Cm3 PRP=6ns

NCI=500NCI=1000NCI=750NCI=600

0 2 4 6 8 10 12 14

10-2

10-1

Cm4 PRP=6ns

Eb/No

Ser

NCI=1000NCI=500NCI=600NCI=750

Eb/No

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Pulse Repetition Period at 110Mb/s

Nbit/Pulse 1 2 3 4 5Modulation POL 2PPM

POL4PPM POL

8PPM POL

16PPM POLCR = 1/3 3 6.05 9.05 12.1 15.15

CR = 1/2 4.5 9.05 13.6 18.15 22.7CR = 2/3 6.05 12.1 18.15 24.2 30.3CR = 3/4 6.8 13.6 20.45 27.25 34.05CR = 7/8 7.95 15.9 23.85 31.8 39.75CR = 1 9.05 18.15 27.25 36.35 45.45CR = Code Rate All PRP values in nanosecond

Low order modulation preferred to minimize gate count/costfor low data-rate devices

July 2003


doc.: IEEE 802.15-03/139r4

Submission



POL4PPM POL

8PPM POL

16PPM POL

CR = 1/3 1.65 3.3 5 6.65 8.3

CR = 1/2 2.5 5 7.45 10 12.45

CR = 2/3 3.3 6.65 10 13.3 16.65

CR = 3/4 3.7 7.45 11.25 14.95 18.7

CR = 7/8 4.35 8.75 13.1 17.5 21.85

CR = 1 5 10 15 20 24.95

CR = Code Rate All PRP values in nanosecond

Low order modulation preferred to enableintermediate data-rate devices

July 2003


doc.: IEEE 802.15-03/139r4

Submission




POL4PPM POL

8PPM POL

16PPM POL

CR = 1/3 0.65 1.35 2.05 2.75 3.45

CR = 1/2 1 2.05 3.1 4.15 5.2

CR = 2/3 1.35 2.75 4.15 5.55 6.9

CR = 3/4 1.55 3.1 4.65 6.2 7.8

CR = 7/8 1.8 3.6 5.45 7.25 9.1

CR = 1 2.05 4.15 6.2 8.3 10.4

Larger PRP preferred to avoid too small inter-position delay !

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Pulse Repetition Period at 1Gb/s



POL4PPM POL

8PPM POL

16PPM POL

CR = 1/3 0.3 0.65 1 1.3 1.65

CR = 1/2 0.5 1 1.5 2 2.5

CR = 2/3 0.65 1.3 2 2.65 3.3

CR = 3/4 0.75 1.5 2.2 3 3.7

CR = 7/8 0.8 1.75 2.6 3.5 4.35

CR = 1 1 2 3 4 5

Larger PRP preferred to avoid too small inter-position delay in PPM

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Manufacturability• Architecture matches full CMOS implementation

– Low cost, single chip product– Using today’s silicon technology

• Simulation proven hardware architecture– SystemC model used (synthesized model available)– Performance and gate complexity estimated from chipset and

FPGA implementation

• Demonstrator in development– 0.13 m CMOS technology

• Size and form factor– Single chip silicon allows small size like PC card, memory stick,

…, and would be usable in portable devices

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Power consumption

• Low power Architecture– Minimum RF front end (low power with respect to

alternative architecture)– Demodulation processed in digital– Channel estimation gates (~2/3 of demodulation count)

used only during frame preamble (<10% of time) – Typical clock frequency is PRP (only RF front end is

high speed)– Digital power consumption will scale as Moore’s law

in future technology

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Scalability

• Low data rate (LDR) permits lower power, lower complexity– Channel estimation power cost can be reduced for low

data rate (need less path, and shorter sequence)

– Simple modulation (polarity) compatible with HDR devices

• High data rate scalable easily– ST expect data rate of up to 750 Mbps shortly

– 1 Gbps theoretically possible for high-end products

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Location awareness

• Relative location (distance between stations) available at almost no cost– Thanks to channel estimation principle

• 2 performance levels possible (implementor choice)– A few decimeters accuracy (simple processing)– A few centimeters accuracy (signal processing of

estimated channel)– Minimal additional hooks in 802.15.3 MAC

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Multipath immunity

• Channel estimation principle allows capture of most received energy – Equivalent to infinite rake architecture

• Excellent performance in worst multipath environment

• Pulse shape/spectrum independent– The receiver architecture don’t need a-priori knowledge

on pulse shape (this is why it is so easy to match specific regulation)

– Dense multipath channel with overlapping pulses don’t degrade performance

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Slotted CAP• CAP period is divided into slots with well-defined slot beginning

– beacon defines CAP duration as well as each slot duration (e.g 10μs)

• Transmitter (Tx) sends frame at the beginning of the slot • Devices consume power to perform CCA (6μs preamble detection) only at the beginning of the

slot – 20ns is uncertainty of frame arrival (thus insured less power consumption than in the case

when the frame can arrive anywhere in 10μs slot assuming STM implementation choices)• Tx receives feedback about frame transmission by means of Imm-ACK• If frame is to be retransmitted, Tx sends frame in randomly selected slot (using a backoff

mechanism)

20ns 20ns 20ns 20ns 20ns

10μs 10μs 10μs 10μs

…

Slotted CAP

July 2003


doc.: IEEE 802.15-03/139r4

Submission

CCA by preamble detection (optional)

• No assumption on frame start• Frame preamble tuning needed for CCA

– Preamble still periodic but shorter (allows continuous correlation without additional H/W for coarse synch.)

– Preamble includes both coarse and fine synchronization (~10μs)

• Power consumption : same as channel estimation phase (during all CCA period of activity) : mW

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Out-of-band rejection filter

• Proposed: use elliptic filter with poles placed at known out-of-band interferers.

e.g. BP 3rd order with pole at 2.45GHz

July 2003


doc.: IEEE 802.15-03/139r4

Submission

Comparison on different pulse shapes

0 2 4 6 8 10 12-190

-180

-170

-160

-150

-140

-130

-120

-110

-1003-7GHz 7 sub-bands

0 2 4 6 8 10 12-190

-180

-170

-160

-150

-140

-130

-120

-110

-100

3-7GHz 7 sub-bands3-7GHz gap@5GHz 5 sub-bands

Pulse P2 BW = 3.3-7.2GHz

At 110Mbps, CM4 or CM3, Link budget margin is TBD dB

BW = 3.3-4.9; 6.1-7.2GHz

At 110Mbps, CM4 or CM3, Link budget margin is TBD dB

Monopulse Adaptive band PPM-UWB system easily accommodates regulation impact on pulse shape

Documents

Doc.: IEEE 802.15-03/139r4 Submission July 2003 Didier Helal and Philippe Rouzet, STMSlide 1 Project: IEEE P802.15 Working Group for Wireless Personal