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High Speed Downlink Packet Access (HSDPA)November 2006 1
High Speed Downlink Packet Access(HSDPA)
Reiner StuhlfauthTraining Centre, Rohde & Schwarz
High Speed Downlink Packet Access (HSDPA)November 2006 2
Motivation:
Release 99 Capabilities for Downlink Packet DataFocus of HSDPA
High Speed Downlink Packet Access (HSDPA)November 2006 3
MotivationRelease 99 Capabilities for Downlink Packet Data
WCDMA release 99 supports:
� Quality of service
� Multimedia services
� Peak data rates of up to (theoretically) 2 Mbps
� 10 ms frame size
� Packet data transmission via� Dedicated channels
� RACH/FACH channels
� Downlink shared channel (DSCH) Notimplementedin products
Only for smallpackets
Limitedefficiency
High Speed Downlink Packet Access (HSDPA)November 2006 4
MotivationRelease 99 Functional Split
DriftRNC
ServingRNC
MSC
SGSN
RNC = Radio Network Controller
SGSN = Serving GPRS Support Node
MSC = Mobile Switching Center
Iub Iur Iu
•Fast power control•Overload control
• Admission control• Initial power and SIR setting• Radio resource reservation• Air interface scheduling for common channels• Downlink code allocation• Overload control
• Mapping RAB QoS parameters into air interface• Air interface scheduling for dedicated channels• Handover control• Outer loop power control and power balancing
Radio network topologyhidden to core network
High Speed Downlink Packet Access (HSDPA)November 2006 5
MotivationFocus of HSDPA
HSDPA is a 3GPP release 5 feature for UMTS FDD/TDD.
Main focus: Enhancements for downlink packet data
� Background Servicesemail delivery, file download, telematics
� Interactive Servicesweb browsing, data base retrieval, server access
� Streaming Servicesaudio/video streaming
Mobility: 0-30 km/h (pedestrian – low speed vehicular)
High Speed Downlink Packet Access (HSDPA)November 2006 6
MotivationReduced Costs and Higher Revenue
Attract new subscribersdue to new services
Decreased costs per bitfor the operator
Downlink peakdata rates
up to 14 Mbit/s
Increased cell anduser throughput
Reduced delay
High Speed Downlink Packet Access (HSDPA)November 2006 7
Technology Overview:
Key FeaturesImpact on Radio Access Network Architecture
PrincipleChannel Structure
High Speed Downlink Packet Access (HSDPA)November 2006 8
Technology OverviewKey Features of HSDPA (I)
Shared Channel transmission:• Channelization codes and transmission power in a cell
are dynamically shared between users.
• A new transport channel High Speed Downlink SharedChannel (HS-DSCH) is introduced.
Adaptive modulation and coding (AMC):• Adaptation of transmission parameters to radio
conditions and terminal capability
• Modulation schemes:– 16-QAM (Quadrature Amplitude Modulation): UE capability– QPSK (Quadrature Phase Shift Keying): mandatory for UE
High Speed Downlink Packet Access (HSDPA)November 2006 9
HSDPA modulation, QPSK + 16 QAMQuadratur Phase Shift Keying
Qt
I
Q
ϕ
Quadraturcomponent
Inphasecomponent
Q(t)
I(t)
It
Q
I
16-QAM
16 Quadratur Amplitude Modulation
1 modulation symbol = 2 bits 1 modulation symbol = 4 bits
High Speed Downlink Packet Access (HSDPA)November 2006 10
Technology OverviewKey Features of HSDPA (II)
Hybrid automatic-repeat-request (HARQ)• Improving robustness against link adaptation errors• UE rapidly requests retransmissions of erroneously receveived data• UE can combine information from the original transmission with that of
later retransmissions (Soft Combining)Fast scheduling in the Node B instead of RNC
• Moving scheduling and processing of retransmissions closer to airinterface
• New MAC-hs (Medium Access Control – high speed) protocol entity inthe Node B
Short transmission time interval of 2ms• Accelerating packet scheduling for transmission
High Speed Downlink Packet Access (HSDPA)November 2006 11
HSDPA: Capacity aspects
+⋅⋅=NSTBC 1log 2
Capacity aspects:
How does HSDPA increase the capacity per user?
1.) Possibility of code combination
2.) Introduction of 16-QAM modulation scheme
3.) Permission of link adaption -> dynamic channel coding
High Speed Downlink Packet Access (HSDPA)November 2006 12
Technology OverviewImpact on Radio Access Network Architecture
Core Network
Radio Network Controller (RNC)
Node B:Scheduling, Adaptive
modulation/coding, HARQ
Node B:Scheduling, Adaptive
modulation/coding, HARQ
UTRAN
UE
High Speed Downlink Packet Access (HSDPA)November 2006 13
Technology OverviewPrinciple Node B:
HS-DPCCH:
Channel Quality (CQ
I)
Packet ACK/NACK
HS-(P)DSCH User DataHS-SCCH Scheduling Information
Generation ofScheduling Information
for the User Databased on User Feedback
HS-D
PCCH
Chan
nel Q
ualit
y (CQ
I)
Pack
etAC
K/NAC
K
UE1 UE2
High SpeedShared Control
Channel
High Speed DedicatedPhysical Control Channel
High Speed(Physical) Downlink
Shared Channel
High Speed Downlink Packet Access (HSDPA)November 2006 14
Technology OverviewChannel Structure
• The HS-DSCH is associated with one downlink Dedicated Physical Channel (DPCH), and one or severalHigh Speed Shared Control Channels (HS-SCCH).
• The number of HS-SCCHs in a HS-SCCH set as seen from the UE can range from a minimum of 1 to amaximum of 4 HS-SCCHs.
Downlink DPCH (R99)Node B UE
HS-DPCCH
Shared Control Channel (HS-SCCH) #1
HS-DSCH
Uplink DPCH (R99)
ACK/NACKQuality indication
Data
Shared Control Channel (HS-SCCH) #2
Shared Control Channel (HS-SCCH) #3
Shared Control Channel (HS-SCCH) #4
Transport Format /Resource IndicatorHARQ Information
High Speed Downlink Packet Access (HSDPA)November 2006 15
New Physical and Transport Channels
HS-(P)DSCHHigh Speed (Physical) Downlink Shared Channel
High Speed Downlink Packet Access (HSDPA)November 2006 16
HSDPA: subframe structure
Radio Frame
10 ms38400 chips
at a chip rate of 3.84 MChips/s
....
666,6 µs2560 chips
at chip rate of 3.84 MChips/s
....
Slot #0 Slot #14
HSDPA subframe = 3 slots2 ms total time
HSDPA subframe versus Rel-99 frame structure
High Speed Downlink Packet Access (HSDPA)November 2006 17
New Physical and Transport ChannelsStructure of Downlink HS-PDSCH
• Spreading Factor 16• Assignment of multiple channelization codes to one UE possible
Slot #0 Slot#1 Slot #2
Tslot = 2560 chips
320 bits for QPSK, 640 bits for 16QAM
1 subframe of 3 slots: 2 ms
HS-DSCH transport channelwith user data
HS-DSCH:transport channel
HS-PDSCH:physical channel
High Speed Downlink Packet Access (HSDPA)November 2006 18
New Physical and Transport ChannelsHS-PDSCH Code Allocation
SF=1
SF=2
SF=4
SF=8
SF=16
SF=32
SF=64
SF=128
SF=256
2,0
2,1
4,08,0
16,032,0
64,0128,0
256,1
256,3256,4256,5256,6256,7256,8256,9
256,10
256,11256,12256,13256,14256,15
16,15
16,116,216,316,416,516,616,716,816,9
16,1016,1116,1216,1316,14
8,1
8,2
8,3
8,4
8,5
8,6
8,7
4,1
4,2
4,3 256,249256,250256,251256,252256,253256,254256,255
256,248
1,032,1
32,31
64,1
64,2
64,3
64,62
64,63128,126
128,127
256,2
128,125
128,124
128,1
128,2
128,3
128,4
128,5
128,6
128,7
32,30
::
256,0All possible HS-PDSCH codes
Possible HS-SCCH codes (example)
CPICHP-CCPCHblocked
High Speed Downlink Packet Access (HSDPA)November 2006 19
New Physical and Transport ChannelsHS-DSCH Coding Chain
CRC attachment toeach transport block
Code block segmentation
Channel Coding
Physical Layer Hybrid-ARQfunctionality
Bit Scrambling
PhCH#1 PhCH#P
Physical channel mapping
HS-DSCH Interleaving
Physical channelsegmentation
Constellation Re-arrangement for
16QAM
Data arrives to the coding unit in form of a maximum ofone transport block once every transmission time interval.
Turbo Coding Rate 1/3
High Speed Downlink Packet Access (HSDPA)November 2006 20
New Physical and Transport ChannelsConstellation Rearrangement
b=0 b=1
b=2 b=3
High Speed Downlink Packet Access (HSDPA)November 2006 21
New Physical and Transport ChannelsHS-DSCH Coding Chain: Example
Example: Coding rate for Fixed reference Channel H-Set 1 (QPSK)acc. to 3GPP TS 25.101:
Equivalent to nom. average information bit rateof 534 kbps (=3202 bits / 3 (Inter TTI) / 2ms)
CRC length = 24 bits for HS-DSCH
Code Rate = 0,67(= 3202 information bits / 4800 binary channel bits per TTI)5 HS-PDSCHs
Rate matching to number of SoftChannel Bits available for this
HARQ process (9600 bits)
Inf. Bit Payload
CRC Addition
Turbo-Encoding(R=1/3)
3202
Code BlockSegmentation
1st Rate Matching 9600
Tail Bits129678
3226
CRC243202
Redundancy VersionSelection
4800
Physical ChannelSegmentation 960
High Speed Downlink Packet Access (HSDPA)November 2006 22
New Physical and Transport Channels
HS-SCCHHigh Speed Shared Control Channel (Downlink)
High Speed Downlink Packet Access (HSDPA)November 2006 23
New Physical and Transport ChannelsHS-SCCH Usage
HS-DSCH
I would like to receive databut I don‘t know where my
HS-DSCH resources are andhow they look like. ?
HS-SCCH
Read the 1st HS-SCCH slotfor HS-DSCH channelization
codes and modulationscheme.
Then, the 2nd and 3rd HS-SCCHslot will tell you aboutTransport block size information,Hybrid-ARQ process information,Redundancy/constellation version,New data indicator.
High Speed Downlink Packet Access (HSDPA)November 2006 24
New Physical and Transport ChannelsStructure of Shared Control Channel (HS-SCCH)
• The HS-SCCH is a fixed rate (60 kbps, SF=128) downlink physical channelused to carry downlink signalling related to HS-DSCH transmission
Slot #0 Slot#1 Slot #2
Tslot = 2560 chips
Data = 40 bits
1 subframe = 2 ms
High Speed Downlink Packet Access (HSDPA)November 2006 25
New Physical and Transport ChannelsTiming Relation between HS-SCCH and HS-PDSCH
• Start of HS-SCCH subframe #0 is aligned with start of P-CCPCH frames.• The HS-PDSCH starts
τHS-PDSCH = 2×Tslot = 5120 chips
after the start of the HS-SCCH.
HHSS--SSCCCCHH
HHSS--PPDDSSCCHH
3×Tslot = 7680 chips
3×Tslot 7680 chips
HS-DSCH sub-frame
τHS-PDSCH (2*Tslot = 5120 chips)
High Speed Downlink Packet Access (HSDPA)November 2006 26
New Physical and Transport ChannelsHS-SCCH Contents
� Channelization Code Set information (7 bits)� Modulation scheme information (1 bit)� Transport block size information (6 bits)� Hybrid-ARQ process information (3 bits)� Redundancy and constellation version (3 bits)� New data indicator (1 bit)� UE identity (16 bits) = H-RNTI
High Speed Downlink Packet Access (HSDPA)November 2006 27
New Physical and Transport ChannelsHS-SCCH: Signalling of HS-PDSCH Code Allocation
C lus
t er c
ode
Indi
cato
r(3b
its)
Tree offset indicator (4 bits)
0 (1/15)
1 (2/14)
2 (3/13)
3 (4/12)
4 (5/11)
5 (6/10)
6 (7/9)
7 (8/8)
0 10 11 12 13 14 151 2 3 4 5 6 7 8 9
PΟ
Decoding notation
Number ofmulti-codesOffset fromleft/right in codetree (SF=16)
11213141516171
12223242526272
13233343536373
14243444546474
15253545556575
16263646566676
17273747576777
18283848586878
7988
192939495969
6109787
110210310410510
5111069686
111211311411
4121151059585
112212312
3131241141049484
113213
2141331231131039383
114
1151421321221121029282
1511411311211111019181Redundant area
SF=16
Code ‘0’ isreserved forcommonchannels
Code offset 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
P=5O=7
code group indicator:xccs,1, xccs,2, xccs,3 = min(P-1,15-P)code offset indicator:xccs,4, xccs,5, xccs,6, xccs,7 = |O-1-P/8 *15|
A cluster of codescan be allocated to a UE:C ch,16,O … C ch,16, O+P-1
Signalled on HS-SCCH ->
High Speed Downlink Packet Access (HSDPA)November 2006 28
New Physical and Transport ChannelsHS-SCCH: Signalling of Transport Block Size
............
65541731430881613
64381721405871492
63241711380861371
TB SizeIndexTB SizeIndexTB SizeIndex
• The Transport Block Size used on HS-DSCH is not signalled explicitly on HS-SCCH• Instead, a Transport Block Size Index ki is signalled which indicates the transport block size:
……4
7943
6332
4021
11QPSK0
Number ofchannelizationcodes
Modulationscheme
Combination iik ,0
Table according to 3GPP TS 25.321, extract from QPSK section
First step:Modulation scheme and number ofchannelization codes as signalledon HS-SCCH determine value k0,i
Second step:Index kt = ki + k0,i determinesHS-DSCH transport block size
Table according to 3GPP TS 25.321, 254 entries in total
kt = ki + k0,i
High Speed Downlink Packet Access (HSDPA)November 2006 29
New Physical and Transport ChannelsHS-SCCH: Signalling of Transport Block Size
Transportation Block Size
Minimum137 bits
Maximum25558 bits
Possible transportation blockSizes complying with
the modulation scheme and number ofHS-PDSCH‘s
Begin depends onParameters: Modulation
scheme and number of HS-PDSCH‘s
High Speed Downlink Packet Access (HSDPA)November 2006 30
New Physical and Transport Channels
HS-DPCCHHigh Speed Dedicated Physical Control Channel (Uplink)
High Speed Downlink Packet Access (HSDPA)November 2006 31
New Physical and Transport ChannelsHS-DPCCH Usage – ACK/NACK
HS-DSCH
All the HS-DSCH data Ireceive is incorrect!
Send me a NACK, maybeI can do something foryou and send the same
packet again.
Maybe I will even send you anew redundancy version.This could increase theprobability that you can
decode the data.
HS-DPCCH:NACK
High Speed Downlink Packet Access (HSDPA)November 2006 32
New Physical and Transport ChannelsHS-DPCCH Usage – CQI
HS-DSCH
I have to deliver regularreports about the channelquality I experience but I
have to do a lot ofcalculations for this.
These reports really help mein deciding who gets the
next data packet and how Ihave to format it.
HS-DPCCH:CQI (Channel Quality Indication)
High Speed Downlink Packet Access (HSDPA)November 2006 33
New Physical and Transport ChannelsStructure of Uplink HS-DPCCH
Subframe #0 Subframe #i Subframe #4
HARQ-ACK CQI= Channel Quality Information
One radio frame Tf = 10 ms
One HS-DPCCH subframe (2 ms)
2×Tslot = 5120 chipsTslot = 2560 chips
• The spreading factor of the HS-DPCCH is 256 (10 bits per uplink slot)• The HS-DPCCH can only exist together with an UL DPCCH (Ded. Phys. Control Channel).• The DPDCH (Dedicated Physical Data Channel), the DPCCH and the HS-DPCCH are I/Q
code multiplexed.
High Speed Downlink Packet Access (HSDPA)November 2006 34
New Physical and Transport ChannelsSpreading for Uplink DPCCH, DPDCHs and HS-DPCCH
IΣ
j
cd,1 β d
Sdpch,n
I+jQ
DPDCH1
Q
cd,3 β d
DPDCH3
cd,5 β d
DPDCH5
cd,2 β d
DPDCH2
cd,4 β d
cc β c
DPCCH
Σ
S
chs
HS-DPCCH
DPDCH4
chs
HS-DPCCHβ hs
β hs
cd,6 β d
DPDCH6
Scrambling
HS-DPCCH
maximum number ofDPDCH is even
maximum number ofDPDCH is odd
High Speed Downlink Packet Access (HSDPA)November 2006 35
5/1506/1518/1529/15312/15415/15519/15624/15730/158
Signalling values for∆ ACK,∆ΝACK and ∆CQI
New Physical and Transport ChannelsGain Factors for UL HS-DPCCH•Power offset ∆HS-DPCCH for each HS-DPCCH slot
•∆HS-DPCCH = ∆ACK for slots carrying ACK
•∆HS-DPCCH = ∆NACK for slots carrying NACK
•∆HS-DPCCH = ∆CQI for slots carrying CQI
•Gain factor βhs defined as
Signalled by higher layers(values 0…8)
∆ −
⋅= 2010DPCCHHS
chs ββ
Quantized amplituderatios for
∆ −
2010DPCCHHS
High Speed Downlink Packet Access (HSDPA)November 2006 36
New Physical and Transport ChannelsTiming Relations for UL HS-DPCCH
m = (TTX_diff /256 ) + 101
TTX_diff is the difference in chips (TTX_diff =0, 256, ....., 38144) between the transmit timing of thestart of the related HS-PDSCH and the transmit timing of the start of the related downlink DPCH frame
m therefore takes one of a set of five possible values according to the 5 possible transmission timingsof HS-DSCH sub-frame relative to the DPCH frame boundary.
UplinkDPCH
HHSS--PPDDSSCCHHaatt UUEE
UUpplliinnkkHHSS--DDPPCCCCHH
Slot #0 Slot #1 Slot #2 Slot #3 Slot #4 Slot #5 Slot #6 Slot #7 Slot #8 Slot #9 Slot #10 Slot #11 Slot #12
τUEP ≈19200 chips = 7,5 slots
m*256 chips
Tslot = 2560 chips
3 * Tslot = 7680 chips
High Speed Downlink Packet Access (HSDPA)November 2006 37
New Physical and Transport ChannelsRound Trip Timing
HS-SCCH Retransmit
HS-PDSCH Retransmit
A/N CQI
18 slots = 12 ms
3 slots2 slots
2 slots
Minimum retransmission delay = 12 ms
2* Tprop + 15.5 slots A
A = Processing times in L1 and MAC-hs
High Speed Downlink Packet Access (HSDPA)November 2006 38
New Physical and Transport ChannelsMore Timing Relations
k:thS-CCPCH
AICH accessslots
SecondarySCH
PrimarySCH
τS-CCPCH,k
10 ms
τPICH
#0 #1 #2 #3 #14#13#12#11#10#9#8#7#6#5#4
Radio framewith (SFN modulo 2) = 0 Radio framewith (SFN modulo 2) = 1
τDPCH,n
P-CCPCH
Any CPICH
PICH for k:thS-CCPCH
n:th DPCH
10 ms
Subframe#0
HS-SCCHSubframes
Subframe#1
Subframe#2
Subframe#3
Subframe#4
Why this timing?
High Speed Downlink Packet Access (HSDPA)November 2006 39
Timing TDPCH of each DPCH – usage
t
+1
-1T 2T
x1(t) = d1(t ) * c1(t)
t
+1
-1T 2T
x(t) = x1(t) + x2(t)
t
+1
-1T 2T
+2
-2
x2(t) = d2(t ) * c2(t)
Sum
0 -> +11 -> -1
Spreaded signals are added in a multi-user scenario,e.g. downlink signal from node B.This will engender an impact on the amplitude ofthe sum signal.
Problem:If the input signal from each user DPCH willhave the same content, like it is in the periodof e.g. the Pilot bits -> The Crest Factor willrise!
Solution:Node B will set a timing TDPCH for eachDownlink DPCH individually to „randomize“ the signal behaviour
High Speed Downlink Packet Access (HSDPA)November 2006 40
High Speed Downlink Packet AccessDL DPCH Timing Offset
P-CCPCH
DL-DPCH
HS-SCCH
HS-PDSCH
UE timing
2slots
T_dpch_offset
1 Radio Frame = 10 ms
Propagation Delay
DL-DPCH
T_txdiff
HS-PDSCH
UL-DPCH
HS-DPCCH
T_dl_ul_offset = 1024 chips
T_UlDpch-HsDpcch = (T_txdiff + 101)*256 chips
Propagation Delay
7.5 slots
DPCH offset 21�alignment ofUL DPCH andHS-DPCCH
High Speed Downlink Packet Access (HSDPA)November 2006 41
High Speed Downlink Packet AccessDL DPCH Timing Offset
P-CCPCH
DL-DPCH
HS-SCCH
HS-PDSCH
UE timing
2slots
T_dpch_offset
1 Radio Frame = 10 ms
Propagation Delay
DL-DPCH
T_txdiff
HS-PDSCH
UL-DPCH
HS-DPCCH
T_dl_ul_offset = 1024 chips
T_UlDpch-HsDpcch = (T_txdiff + 101)*256 chips
Propagation Delay
7.5 slots
DPCH offset 22�10% overlap ofUL DPCH andHS-DPCCH
High Speed Downlink Packet Access (HSDPA)November 2006 42
High Speed Downlink Packet AccessDL DPCH Timing Offset
P-CCPCH
DL-DPCH
HS-SCCH
HS-PDSCH
UE timing
2slots
T_dpch_offset
1 Radio Frame = 10 ms
Propagation Delay
DL-DPCH
T_txdiff
HS-PDSCH
UL-DPCH
HS-DPCCH
T_dl_ul_offset = 1024 chips
T_UlDpch-HsDpcch = (T_txdiff + 101)*256 chips
Propagation Delay
7.5 slots
DPCH offset 26�50% overlap ofUL DPCH andHS-DPCCH
High Speed Downlink Packet Access (HSDPA)November 2006 43
High Speed Downlink Packet AccessDL DPCH Timing Offset
� DL DPCH timing offset results in a propable„non slot alignment“ between HS-DPCCH and the DPCHslot
� 1 slot = 2560 chips = 10 symbols
50% overlap
slotalignment
Remark
1102938475665748392
0110
realtive timing difference DPCH vs. HS-DPCCH(symbols)
T_dpch_offset(symbols)
High Speed Downlink Packet Access (HSDPA)November 2006 44
Data Rates10 or 14 Mbps?
High Speed Downlink Packet Access (HSDPA)November 2006 45
Data RatesHow are 14.4 Mbps derived?
• 1 slot HS-PDSCH (equivalent to 10 ms / 15 = 666.7 us) using 16 QAM contains 640 bits
• Maximum 15 HS-PDSCH codes can be allocated to a UE
• 15 HS-PDSCHs therefore result in a gross bit rate of
15* 640 bits / 666.7 us = 14.4 Mbps This does not include any channelcoding and is therefore a rather
theoretical value
Slot #0 Slot#1 Slot #2
Tslot = 2560 chips
320 bits for QPSK, 640 bits for 16QAM
1 subframe of 3 slots: 2 ms
High Speed Downlink Packet Access (HSDPA)November 2006 46
Data RatesUser Equipment Classes
28800363015Category 12*
14400363025Category 11*
17280027952115Category 10
17280020251115Category 9
13440014411110Category 8
11520014411110Category 7
67200729815Category 6
57600729815Category 5
38400729825Category 4
28800729825Category 3
28800729835Category 2
19200729835Category 1
Total numberof soft channel
bits
Maximum number ofbits of an HS-DSCH
transport blockreceived within
an HS-DSCH TTI
Minimuminter-TTIinterval
Maximumnumber of HS-DSCH codes
received
HS-DSCH category
1.2 Mbps class
3.6 Mbps class
7 Mbps class
10 Mbps class
*QPSK only
3GPP
TS
25.3
06
High Speed Downlink Packet Access (HSDPA)November 2006 47
Adaptive Modulation and Coding
MotivationPrinciple
Channel Quality Reporting
High Speed Downlink Packet Access (HSDPA)November 2006 48
Adaptive Modulation and CodingPrinciple
� HS-DSCH data rate is adjusted bymodifying
� modulation scheme
� effective code rate
� number of HS-PDSCH codes
� Decision based on channel quality reportsfrom UE
HS-DSCH,e.g. 16QAM,code rate 3/4
HS-DSCH,e.g. QPSK,code rate 1/2
High Speed Downlink Packet Access (HSDPA)November 2006 49
Adaptive Modulation and CodingChannel Quality Reporting
HS-DSCH modulation /coding adapted acc. toproposed CQI
HS-DPCCH:proposed CQI(every 2ms…160ms)
……………
-216-QAM5716824
-116-QAM5716823
016-QAM5716822
016-QAM5655421
016-QAM5588720
016-QAM5528719
016-QAM5466418
016-QAM5418917
016-QAM5356516
0QPSK5331915
0QPSK4258314
0QPSK4227913
0QPSK3174212
09600……………
XRV
NIRReferencepower
adjustment ∆Modulati
on
Numberof
HS-PDSCH
TransportBlock Size
CQIvalue
UE proposes CQI value so thatHS-DSCH transport block errorprobability would not exceed 0.1
Table according to 3GPP TS 25.214
High Speed Downlink Packet Access (HSDPA)November 2006 50
Adaptive Modulation and CodingChannel Quality Reporting
……………
-216-QAM5716824
-116-QAM5716823
016-QAM5716822
016-QAM5655421
016-QAM5588720
016-QAM5528719
016-QAM5466418
016-QAM5418917
016-QAM5356516
0QPSK5331915
0QPSK4258314
0QPSK4227913
0QPSK3174212
09600……………
XRV
NIRReferencepower
adjustment ∆Modulati
on
Numberof
HS-PDSCH
TransportBlock Size
CQIvalue
3GPP TS 25.214 contains 5different tables for:
� Categories 1-6
� Categories 7-8
� Category 9
� Category 10
� Categories 11,12
Each table contains definitions forCQI values 0…30
High Speed Downlink Packet Access (HSDPA)November 2006 51
Adaptive modulation and coding (AMC)
Tests 1&2 2codesx4TS
0
200
400
600
800
1000
1200
-2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
SIR (dB)
Thro
ughp
ut (b
its/s
ub-fr
ame)
QPSK 240 QPSK 253QPSK 267 QPSK 282QPSK 298 QPSK 315QPSK 332 QPSK 351QPSK 370 QPSK 391QPSK 413 QPSK 436QPSK 461 QPSK 487QPSK 514 QPSK 543QPSK 573 QPSK 605QPSK 639 QPSK 67516-QAM 675 16-QAM 71216-QAM 752 16-QAM 79416-QAM 839 16-QAM 88616-QAM 936 16-QAM 98816-QAM 1043 16-QAM 110216-QAM 1163
High Speed Downlink Packet Access (HSDPA)November 2006 52
CQI encoding with (20,5) code
SIR
Thr
ough
put
high
low
highlow
≡CQIn
≡CQIn-1
≡CQIn-2
≡CQIn+2
≡CQIn+1
Prevailing conditions of SIR
Optimumthroughput if the UE
reports CQIn
SIR changes, CQI reporting must follow!
If misunderstandingof CQI leeds to
usage of CQI closeto optimum, impact
is not too serious
If misunderstandingof CQI leeds to
usage of CQI remoteto optimum, impactis serious-> data rate
slumps down
CQI is using (20,5) code to reduce mean BER, like e.g. Gray encoding
High Speed Downlink Packet Access (HSDPA)November 2006 53
New Physical and Transport ChannelsChannel Coding for CQI
•Channel Coding for CQI is using a (20,5) code
•Code words of the (20,5) code are a linear combinationof the 5 basis sequences denoted Mi,n
•Channel quality information bits are converted to binaryrepresentation: a0, a1, a2, a3, a4
•Output bits bi are then given by:
i = 0…19
1000019100001810000171000016100001511111141111013111011211100111101110110109110018110007101116101105101014101003100112100101100010
Mi,4Mi,3Mi,2Mi,1Mi,0i
2mod)( ,
4
0Mab ni
nni ×=∑
=
High Speed Downlink Packet Access (HSDPA)November 2006 54
Adaptive Modulation and CodingChannel Quality Reporting
……………
-216-QAM5716824
-116-QAM5716823
016-QAM5716822
016-QAM5655421
016-QAM5588720
016-QAM5528719
016-QAM5466418
016-QAM5418917
016-QAM5356516
0QPSK5331915
0QPSK4258314
0QPSK4227913
0QPSK3174212
09600……………
XRV
NIRReferencepower
adjustment ∆Modulati
on
Numberof
HS-PDSCH
TransportBlock Size
CQIvalue
Example: UE proposes CQI value 19.
CQI value 19 corresponds to
�Transport Block Size 5287 bits
�5 HS-PDSCHs
�16QAM Modulation
UE assumes:
� HS-DSCH power [dB]:
�Γ signalled by higher layers
�Virtual IR buffer NIR
�Redundancy version XRV
∆+Γ+= CPICHHSPDSCH PP
High Speed Downlink Packet Access (HSDPA)November 2006 55
Hybrid ARQ
Protocol DefinitionMotivationPrinciple
HS-DSCH Coding ChainPhysical Layer HARQ Functionality
Redundancy Version CodingHARQ Processes
High Speed Downlink Packet Access (HSDPA)November 2006 56
Hybrid ARQProtocol Definition
• ARQ / Automatic Repeat Request:Receiver detects errors and requests retransmissions of erroneous packets
• HARQ / Hybrid-ARQ:• Coding is applied to transmission packets
• Receiver does not delete received symbols when decoding failsbut combines the new transmission with the old one in the buffer
• Two ways of operating:•Identical retransmission (Chase Combining)•Non-identical retransmission (Incremental Redundancy)
Data
NACK
Data
ACK
High Speed Downlink Packet Access (HSDPA)November 2006 57
Hybrid ARQChase Combining
Turbo Encoder output (36 bits)
Rate Matching to 16 bits (Puncturing)
Chase Combining at receiver
Systematic BitsParity 1Parity 2
Systematic BitsParity 1Parity 2
Systematic BitsParity 1Parity 2
Original Transmission Retransmission
High Speed Downlink Packet Access (HSDPA)November 2006 58
Hybrid ARQIncremental Redundancy
Turbo Encoder output (36 bits)
Rate Matching to 16 bits (Puncturing)
Incremental Redundancy Combining at receiver
Systematic BitsParity 1Parity 2
Systematic BitsParity 1Parity 2
Systematic BitsParity 1Parity 2
Original Transmission Retransmission
High Speed Downlink Packet Access (HSDPA)November 2006 59
Hybrid ARQMotivation
Limitations of Adaptive Modulation and Coding:- accuracy of CQI reporting- effect of delay
HARQ can be understood as an implicit link adaptation technique:- Does not rely on explicit C/I or similar measurements- Link layer acknowledgements are used for re-transmission decisions- Autonomously adapts to the instantaneous channel conditions- Insensitive to measurement error and delay
AMC provides the coarse data rate selection.
H-ARQ provides for fine data rate adjustment basedon channel conditions.
Combination ofAMC and HARQ
High Speed Downlink Packet Access (HSDPA)November 2006 60
Hybrid ARQHS-DSCH Coding Chain
CRC attachment toeach transport block
Code block segmentation
Channel Coding
Physical Layer Hybrid-ARQfunctionality
Bit Scrambling
PhCH#1 PhCH#P
Physical channel mapping
HS-DSCH Interleaving
Physical channelsegmentation
Constellation Re-arrangement for
16QAM
Data arrives to the coding unit in form of a maximum ofone transport block once every transmission time interval.
Redundancy Versiondetermined byparameters r and s
Constellationdetermined byparameter b
Signalled to UEon HS-SCCH
Signalled to UEon HS-SCCH
Turbo Coding Rate 1/3
High Speed Downlink Packet Access (HSDPA)November 2006 61
Hybrid ARQPhysical Layer HARQ Functionality (I)
RM P1_1
RM P2_1
RM S
RM P1_2
RM P2_2
Nsys
Np1
Np2
Nt,sys
Nt,p1
Nt,p2
First RateMatching
VirtualIR Buffer
Second RateMatching
Systematic bits
Parity 1 bits
Parity 2 bits
RV Parameterss and r
Fromturbocoder
matches the number of bits to thenumber of soft channel bits available inthe virtual IR buffer (puncturing)
To P
hysi
calC
hann
elS
egm
enta
tion
IR buffer size canbe configured
matches the number of bits to the number ofphysical channel bits in the HS-PDSCH set;generates different redundancy versionswhich mainly influences HARQ performance
Turbo Coder outputs Systematic bitsand two streams of parity bitsSystematic bits are identical to the inputbits to the turbo coder
High Speed Downlink Packet Access (HSDPA)November 2006 62
Hybrid ARQPhysical Layer HARQ Functionality (II)
RM P1_1
RM P2_1
RM S
RM P1_2
RM P2_2
Nsys
Np1
Np2
Nt,sys
Nt,p1
Nt,p2
First RateMatching
VirtualIR Buffer
Second RateMatching
Systematic bits
Parity 1 bits
Parity 2 bits
From
turb
oco
der
3* 7
20 b
its=
2160
bits
are
arriv
ing
To P
hysi
calC
hann
elS
egm
enta
tion,
96
0 bi
tsav
aila
ble
on H
S-P
DS
CH
Example assumptions:
• 1 HS-PDSCH code with QPSK available (960 bits)
• 720 bits input to turbo coder -> (720 * 3) bits output of turbo coder
• Virtual IR buffer size = 1920 bits
Virtual IRbuffer size= 1920 bits
720 bits
720 bits
720 bits
2160 bits have to be matched to1920 bits by puncturing (-11%)
1920 bits have to be matched to960 bits by puncturing (-50%),
High Speed Downlink Packet Access (HSDPA)November 2006 63
Hybrid ARQSignalling of Redundancy Version (QPSK) on HS-SCCH
Redundancy Version Coding Sequences are signalled on HS-SCCH, example:-{0,2,5,6}: one initial transmission + 3 retransmissions with different r and s parameters
307
316
205
214
103
112
001
010
rsXrv(value)
Initial transmission
1st retransmission
2nd retransmission
3rd retransmission
s=1: systematic bits are prioritizeds=0: non systematic bits are prioritized
r (range 0 to 3 for QPSK) influences:• input parameter of puncturing or
(together with s) of repetitionalgorithm defined in TS 25.212
• selection of parity bits
High Speed Downlink Packet Access (HSDPA)November 2006 64
Hybrid ARQSignalling of Redundancy Version (16QAM) on HS-SCCH
0117
3016
2015
1014
1103
1112
0001
0010
brsXrv (value)
Redundancy Version Coding Sequences are signalled on HS-SCCH, example:-{6,4,0,5}: Chase combining (no change in s and r parameters, i.e. same redundancyversion) with 4 possible constellations
Initial transm.
3rd retransm.1st retransm.
2nd retransm.
Definition ofparameter s asfor QPSK
r (range 0 to 1 for 16QAM) influences inputparameter of puncturing or (together with s) ofrepetition algorithm defined in TS25.212 and thusselection of parity bits
b (range 0 to 3) describesconstellation rearrangementto average reliability of bits
High Speed Downlink Packet Access (HSDPA)November 2006 65
HARQ principle: Multitasking
t
BS, Tx
UE, Tx
Data Data
∆t
Demodulate, decode, descramble,despread, check CRC, etc.
ACK/NACK
Minimum processing time for UEreceiver
Data Data
UE, Tx Demodulate, decode, descramble,despread, check CRC, etc.
Remark, for being able to receive an Inter-TTI of 1 it is required tohandle 6 parallel HARQ processes
ACK/NACK
High Speed Downlink Packet Access (HSDPA)November 2006 66
Hybrid ARQHARQ Processes
asynchronous DL - synchronous UL
Number of H-ARQ processes = 1..8 per UE
High Speed Downlink Packet Access (HSDPA)November 2006 67
MAC-hs Protocol Entity
Overall Protocol ArchitectureFunctions and Architecture UTRAN and UE Side
MAC-d Flows and Priority Queue HandlingMAC-hs Protocol Data Unit
MAC-hs Reset
High Speed Downlink Packet Access (HSDPA)November 2006 68
MAC-hs Protocol EntityProtocol Architecture with New MAC-hs Protocol
L2
L1
HS-DSCH
FP
RLC
L2
L1
HS-DSCH
FP
Iub/ Iur
PHY
MAC
PHY
RLC
Uu
MAC-hs
MAC-d
New protocol entity in Node BOne entity for each cell supporting HSDPA
UE
Node B
RNC
MAC = Medium Access ControlRLC= Radio Link ControlFP = Frame Protocol
High Speed Downlink Packet Access (HSDPA)November 2006 69
MAC-hs Protocol EntityUE Side MAC Architecture
MAC-d
FACH RACH
DCCH DTCHDTCH
DSCH DCH DCH
MAC Control
USCH( TDD only )
CPCH( FDD only )
CTCHBCCH CCCH SHCCH( TDD only )
PCCH
PCH FACH
MAC-c/sh
USCH( TDD only )
DSCH
MAC-hs
HS-DSCH
Associated UplinkSignalling
Associated DownlinkSignalling
High Speed Downlink Packet Access (HSDPA)November 2006 70
MAC-hs Protocol EntityUE Side MAC-hs Architecture
MAC-hs
MAC – Control
Associated Uplink Signalling
To MAC-d
Associated Downlink Signalling
HS-DSCH
HARQ
Reordering Reordering
Re-ordering queue distribution
Disassembly Disassembly
High Speed Downlink Packet Access (HSDPA)November 2006 71
NBAP: HS-DSCH Information to Modify (Extract)
9.2.1.52BM>>>RLC Mode
…
9.2.1.38AM>>>>MAC-d PDU Size9.2.1.53IM>>>>SID
1..<maxnoofMACdPDUindexes>
>>>MAC-d PDU Size Index9.2.1.38AaO>>>MAC-hs Guaranteed Bit Rate9.2.1.38BM>>>MAC-hs Window Size9.2.1.24EO>>>Discard Timer9.2.1.56aM>>>T19.2.1.53HM>>>Scheduling Priority Indicator
Shall only refer to an HS-DSCHMAC-d flow already existing in theold configuration.Multiple Priority Queues can beassociated with the same HS-DSCH MAC-d Flow ID.
HS-DSCHMAC-d FlowID 9.2.1.31I
M>>>Associated HS-DSCH MAC-dFlow
9.2.1.49CM>>>Priority Queue ID>>Add Priority Queue
M>CHOICE Priority Queue0..<maxnoofPrioQueues>Priority Queue Information
….
Semantics DescriptionIE Typeand
Reference
RangePresenceIE/Group Name
High Speed Downlink Packet Access (HSDPA)November 2006 72
If the F field is set to "0" the F field isfollowed by a SID field. If the F field isset to "1" the F field is followed by aMAC-d PDU.
Size Index Identifier (3 bit), size ofset of consecutive MAC-d PDUs;MAC-d PDU size for a given SIDconfigured by higher layers andindependent for each Queue ID
MAC-hs Protocol EntityMAC-hs Protocol Data Unit (PDU)
Queue ID TSN SID1 N1 F1 SID2 N2 F2 SIDk Nk Fk
MAC-hs header MAC-hs SDU Padding (opt)MAC-hs SDU
Mac-hs payload
VF
• Each MAC-hs SDU equals a MAC-d PDU (format as for the non HS-DSCH case)• A maximum of one MAC-hs PDU can be transmitted in a TTI per UE• The MAC-hs header is of variable size
Version Flag (1 bit), extensioncapabilities for PDU format(value 1 reserved in rel5)
Queue ID (3 bit) providesidentification of the reorderingqueue in the receiver
Transmission SequenceNumber (6 bit) for reorderingpurposes/in-sequence delivery
Number of consecutive MAC-d PDUs withequal size (7 bits); maximum number ofPDUs transmitted in a single TTI shall be 70
High Speed Downlink Packet Access (HSDPA)November 2006 73
HSDPA: MAC-hs SDU and MAC-hs PDU
Q ueue ID TSN SID 1 N 1 F 1 SID 2 N 2 F 2 SID k N k F k
M A C -hs header M A C -hs SD U P adding (opt)M AC -hs SD U
M ac-hs payload
V F
MAC-hs PDU
MAC-d PDU MAC-d PDUEach MAC-hs SDU correspondsto 1 MAC-d PDU
1 MAC-hs PDU is sent every TTI of 2msec
High Speed Downlink Packet Access (HSDPA)November 2006 74
HSDPA: MAC-hs SDU and MAC-hs PDU
MAC-hs PDU
MAC-d PDUSize A
MAC-d PDUSize B
Identifies size of set ofConsecutive MAC-d PDU‘s
1 MAC-hs PDU is sent every TTI of 2msec
Queue ID TSN SID 1 N 1 F1 SID 2 N 2 F2 SID k N k Fk
MAC -hs header MAC -hs SDU Padding (opt)MAC -hs SDU
Mac -hs payload
VF
MAC -hs SDU
Number ofMAC-d PDU‘s,Size A
Identifies size of set of consecutive MAC-dPSU‘s, here of size B
Number of MAC-d PDU‘s of size B
High Speed Downlink Packet Access (HSDPA)November 2006 75
MAC-hs Protocol EntityReordering of MAC-hs PDUs on UE Side
MAC-hs PDUTSN 0
MAC-hs PDUTSN 1
MAC-hs PDUTSN 3
Received MAC-hs PDUs
Delivery toDisassembly Entity
Next expected TSN = 2
TSN = 3 > Next expected TSNStart Reordering Release Timer T1
Reo
rder
ing
Que
ue
High Speed Downlink Packet Access (HSDPA)November 2006 76
Added or Reconfigured MAC-d Flow(in „Added or reconfigured DL TrCH Information“, TS 25.331 (RRC))
REL-5The MAC-hs queue ID isunique across all MAC-d flows.
Integer(0..7)MP>MAC-hs queue IdREL-5<1 to maxQueueID>OPMAC-hs queue to delete listREL-5Integer(0..7)MP>>MAC-d PDU size indexREL-5Integer(1..5000)MP>>MAC-d PDU size
REL-5Mapping of the different MAC-d PDU sizes configured for theHS-DSCH to the MAC-d PDUsize index in the MAC-hsheader.
<1 to maxMACdPDUsizes>
OP>MAC-d PDU size Info
REL-5Integer(4, 6, 8,12, 16, 24, 32)
MP>MAC-hs window size
REL-5Timer (in milliseconds) whenPDUs are released to theupper layers even thoughthere are outstanding PDUswith lower TSN values.
Integer(10, 20,30, 40, 50, 60,70, 80, 90, 100,120, 140, 160,200, 300, 400)
MP>T1
REL-5MAC-d FlowIdentity10.3.5.7c
MP>MAC-d Flow Identity
REL-5The MAC-hs queue ID isunique across all MAC-d flows.
Integer(0..7)MP>MAC-hs queue Id
REL-5<1 to maxQueueID>OPMAC-hs queue to add or reconfigure list
VersionSemantics descriptionType andreference
MultiNeedInformation Element/Group name
SID
High Speed Downlink Packet Access (HSDPA)November 2006 77
MAC-hs Protocol EntityMAC-hs Reset
If a reset of the MAC-hs entity is requested by upper layers, the UE shall:
�flush soft buffer for all configured HARQ processes;
�stop all active re-ordering release timer (T1), set all timer T1 to their initial value;
�start TSN with value 0 for the next transmission on every HARQ process;
�initialise the variables RcvWindow_UpperEdge and next_expected_TSN to theirinitial values;
�disassemble all MAC-hs PDUs in the re-ordering buffer and deliver all MAC-dPDUs to the MAC-d entity;
�flush the re-ordering buffer.
�and then:
�indicate to all AM RLC entities mapped on HS-DSCH to generate a status report.
High Speed Downlink Packet Access (HSDPA)November 2006 78
RRC Protocol(Radio Resource Control)
Signalling of Physical Layer ParametersMobility
High Speed Downlink Packet Access (HSDPA)November 2006 79
RRC ProtocolSignalling of Physical Layer ParametersPhysical layer parameters signalled to UE / Node B:
• HS-SCCH set to be monitored
• Repetition factor of ACK/NACK: N_acknack_transmit
• Channel Quality Indicator feedback cycle k
• Repetition factor of CQI: N_cqi_transmit
• Measurement power offset Γ
• Power offsets for ACK, NACK, CQI
• [Release 6: Status of preamble/postamble transmission:HARQ_preamble_mode]
High Speed Downlink Packet Access (HSDPA)November 2006 80
RRC ProtocolDownlink HS-PDSCH Information
REL-5MeasurementFeedbackInfo10.3.6.40a
OPMeasurement Feedback Info
REL-5HS-SCCHInfo10.3.6.36a
OPHS-SCCH Info
VersionSemanticsdescription
Type andreference
MultiNeedInformation Element/Groupname
Contained in:Cell Update ConfirmPhysical Channel ReconfigurationRadio Bearer ReconfigurationRadio Bearer ReleaseRadio Bearer SetupTransport Channel Reconfiguration
High Speed Downlink Packet Access (HSDPA)November 2006 81
RRC ProtocolHS-SCCH Info
REL-5Integer(0..127)
MP>>>HS-SCCHChannelisation Code
REL-51 to<maxHS-SCCHs>
MP>>HS-SCCHChannelisation CodeInformation
REL-5DL Scramblingcode to beapplied for HS-DSCH and HS-SCCH. Defaultis samescrambling codeas for theprimary CPICH.
Secondaryscramblingcode10.3.6.74
MD>>DL Scrambling Code
REL-5>FDD
REL-5MPCHOICE mode
VersionSemanticsdescription
Type andreference
MultiNeedInformationElement/Group name
High Speed Downlink Packet Access (HSDPA)November 2006 82
RRC ProtocolMeasurement Feedback Info
REL-5Refer toquantizationof the poweroffset in [28]
Integer(0..8)
MP>>∆CQI
REL-5Integer(1..4)
MP>>CQI repetition factor
REL-5Inmilliseconds.
Integer(0, 2, 4, 8,10, 20, 40,80, 160)
MP>>CQI Feedback cycle, k
REL-5Default Poweroffsetbetween HS-PDSCH andP-CPICH/S-CPICH. IndB.
Real(-6 ..13 by stepof 0.5)
MP>>POhsdsch
REL-5>FDD
Version
Semanticsdescription
Type andreference
MultiNeedInformationElement/Group name
High Speed Downlink Packet Access (HSDPA)November 2006 83
RRC ProtocolUplink DPCH Power Control Info
REL-5Integer(1..4)OP>>Ack-Nack repetition factor
REL-5refer to quantization ofthe power offset in [28]
Integer(0..8)
OP>>∆NACK
REL-5Refer to quantizationof the power offset in[28]
Integer(0..8)
OP>>∆ACK
In dBInteger (1, 2)CV-algo>>TPC step size
Specifies algorithm tobe used by UE tointerpret TPCcommands
Enumerated(algorithm 1,algorithm 2)
MP>>Power Control Algorithm
In number of framesInteger(0..7)MP>>SRB delay
In number of framesInteger (0..7)MP>>PC Preamble
In dBInteger(-164,..-6by step of 2)
MP>>DPCCH Power offset
>FDD
MPCHOICE mode
VersionSemanticsdescription
Type andreference
MultiNeedInformation Element/Group name
High Speed Downlink Packet Access (HSDPA)November 2006 84
RRC ProtocolAdded or Reconfigured DL TrCH information
VersionSemanticsdescription
Type andreference
MultiNeedInformation Element/Groupname
REL-5Added orreconfiguredMAC-d flow10.3.5.1a
OP>>Added or reconfigured MAC-dflow
REL-5HARQ info10.3.5.7a
OP>>HARQ Info
REL-5Note 1>HS-DSCH
Contained in:Cell Update ConfirmHOV to UTRAN commandRadio Bearer ReconfigurationRadio Bearer ReleaseRadio Bearer SetupTransport Channel Reconfiguration
High Speed Downlink Packet Access (HSDPA)November 2006 85
RRC ProtocolHARQ Info
REL-5Maximum number ofsoft channel bitsavailable in the virtualIR buffer [27]
Integer(800 .. 16000 bystep of 800, 17600 ..32000 by step of 1600,36000 .. 80000 by step of4000, 88000 .. 160000 bystep of 8000, 176000 ..304000 by step of 16000)
MP>>>Process Memory size
REL-5<1 toMaxHProcesses>
MP>>Memory size
REL-5>Explicit
REL-5UE shall applymemory partitioning ofequal size across allHARQ processes
>Implicit
REL-5MPCHOICE Memory Partitioning
REL-5Integer (1..8)MPNumber of Processes
VersionSemanticsdescription
Type and referenceMultiNeedInformation Element/Groupname
High Speed Downlink Packet Access (HSDPA)November 2006 86
RRC ProtocolMobility•HS-DSCH sent from one BTS only
•Associated DCH sent from all cellsRNC
DCH + HS-DSCH
DCH
Iub
High Speed Downlink Packet Access (HSDPA)November 2006 87
RRC ProtocolMobility
Terminology:
• Serving HS-DSCH radio link: The radio link that the HS-PDSCH physical channel(s)allocated to the UE belongs to.
• Serving HS-DSCH cell: The cell associated with the UTRAN access point performingtransmission and reception of the serving HS-DSCH radio link for a given UE. Theserving HS-DSCH cell is always part of the current active set of the UE.
• Serving HS-DSCH Node B: A role a Node B may take with respect to a UE havingone or several HS-PDSCHs allocated. The serving HS-DSCH Node B is the Node Bcontrolling the serving HS-DSCH cell.
Procedures:
• Mobility for HSDPA is based on existing (Release 99) RRC handover procedures.
„Serving HS-DSCH Radio LinkIndicator“ in „Downlink
Information for each Radio Link“
High Speed Downlink Packet Access (HSDPA)November 2006 88
RRC ProtocolServing HS-DSCH Cell Change
NodeB NodeB
MAC-hs
NodeB NodeB
MAC-hs
Source HS-DSCH Node B
Target HS-DSCH Node B
ServingHS-DSCHradio link
ServingHS-DSCHradio link
s t
RNC RNC
Establishment of new HARQentities in target Node B
High Speed Downlink Packet Access (HSDPA)November 2006 89
RRC ProtocolExample: Inter Node B Hard Handover
UE Target Node B Source Node B SRNCHOV DecisionRL Setup
RL ReconfigurationMAC-hs release
MAC-hs setup
RL ReconfigurationTransport ChannelReconfiguration incl.
MAC-hs Reset Indicator
Stop Tx/Rx insource cell
Start Tx/Rx intarget cell
MAC-hs ResetTransport Channel
Reconfiguration Complete
RL DeletionStop Rx/Tx
Start Rx/Tx
High Speed Downlink Packet Access (HSDPA)November 2006 90
Release 6 IssuesHS-DPCCH ACK/NACK Enhancement
�Enhancements to the HS-DPCCH ACK/NACK transmission�Transmission of a layer 1 preamble and postamble
�Objective:�Improve ACK/NACK decoding reliability�Enable current performance with lower HS-DPCCH power�Improved coverage for DCH or E-DCH
High Speed Downlink Packet Access (HSDPA)November 2006 91
Thank you for your attention!
Comments and questionswelcome!