Hsdpa Training

8/13/2019 Hsdpa Training

http://slidepdf.com/reader/full/hsdpa-training 1/47

1 © NOKIA WCDMA RAN / 15.11.2004 / HSDPA BP Confidential – Non Binding – Company Confidential

HSDPAImplementation

andPerformance

Antti KuurneHSDPA BP

02 Dec 04

Internal use only. Forcustomercommunication ,agree with HSDPABusiness Program




Outline

• HSDPA vs. R99 architecture

• HSDPA features

• HSDPA Performance



HSDPA Overview – changes to

R99 architecture




Architecture Change 2(5)

RNC

MAC-d MAC-sh

BTS

MAC-hs

Iub

Packet scheduling forHSDPA is moved from

RNC to BTS




• Peak data rate 1.8Mbit/s (in 1st release and later up to 10.7Mbit/s)

• Reduced (re)transmission delays

• Node-B based fast packet scheduling

• Clearly improved spectral efficiency

• Improved Iub efficiency

• Improved baseband efficiency

HSDPA - Taking WCDMA to the Next Stage

HSDPA

Adaptivemodulation and

coding

Data rates are optimizeddynamically during the sessionaccording to radio link quality. Thisensures highest possible data ratesto end-users.

Fastscheduling

To improve QoS data packages arefurther compressed and BTSschedules data transmission insteadof RNC. Fast interleaving(2ms).

Fastretransmission

Data retransmission is handled byBTS. UE combines correct bits fromoriginal transmission and retransmission (and Hard ARQ). Thisprovides fastest possible response.




Adaptive Modulation and CodingAchievable HSDPA Peak Data Rates

Modulation Code rateSF Throughput(10 codes)

Throughput(15 codes)

Throughput(5 codes)

QPSK

1/4

2/4

3/4

16

16

16

1.2 Mbps

2.4 Mbps

3.6 Mbps

1.8 Mbps

3.6 Mbps

5.3 Mbps

600 kbps

1.2 Mbps

1.8 Mbps

16QAM

1/4

2/4

3/4

16

16

16

2.4 Mbps

4.8 Mbps

7.2 Mbps

3.6 Mbps

7.2 Mbps

10.7 Mbps

1.2 Mbps

2.4 Mbps

3.6 Mbps

14,4 Mbps with4/4 coding

(theoretical)

Uncoded bitrate of4,8Mbps

(Hype, not a userbit rate)

Uncodedbitrate of2,4Mbps

(Hype, not auser bit rate)




HSDPA - general principle

• Fast scheduling is done directly in Node-B based onfeedback information from UE and knowledge of currenttraffic state.

UE2

Channel quality(CQI, Ack/Nack, TPC)


Data

Data

Users may be time and/or code multiplexed

New base station functions• HARQ retransmissions

• Modulation/coding selection

• Packet data scheduling (short TTI)

UE1

0 20 40 60 80 100 120 140-2

02468

10121416

Time [number of TTIs]

QPSK1/4

QPSK2/4

QPSK3/4

16QAM2/4

16QAM3/4

In

stantaneousEsNo[dB]






HSDPA with QPSK and 5 codes

QPSK

1/4

Modulation Code rate

2/43/4

16

SF

1616

16QAM2/4

3/4

16

16

1.2 Mbps


2.4 Mbps3.6 Mbps

4.8 Mbps

7.2 Mbps

1.8 Mbps


3.6 Mbps5.3 Mbps

7.2 Mbps

10.7 Mbps

600 kbps

Throughput(5 codes)

1.2 Mbps1.8 Mbps

2.4 Mbps

3.6 Mbps

• Maximum number of HSDPA users per BTS: 16

• HS-DSCH is transmitted to one cell at a time from the BTS

• Time multiplexed between different cells of the BTS

• Up to 3 cells per BTS can be enabled for HSDPA

• Maximum HS-PDSCH codes per cell: 5

• Maximum HS-SCCH codes per cell: 1

• Maximum HS-PDSCH codes per UE: 5

• HSDPA channel encoding/decoding functionality

• HSDPA ARQ handling for MAC-hs

• HS-DSCH link adaptation based on CQI from the UEs

HSDPA functionalityPeak data rates up to 1.8 Mbit/s

HSDPA

AMC

Frame SizeH-ARQ

Spreading

& Multip.




HSDPA mobility handling withDCH switching

• When entering region withoutHSDPA support, HS-DSCH to DCHswitching is performed

• Packet transmission continues onDCH

• HS-DSCH can be reallocated whenuser returns to HSDPA region (inconnection with RRC statetransitions)

• HS-DSCH to DCH switching isperformed also in case of inter-

frequency and inter-RAT handovers

• Radio bearer is mapped to DCH of 0

kbit/s and the user has a signalingradio bearer active only

• Separate parameter sets for HSDPAUEs in order to control the switching -> extended HSDPA coverage

• If still enough data in buffer, DCH is

allocated• To avoid ping-ponging between the

DCH and the HS-DSCH there isincluded a guard timer for operator’scontrol

• The following inter-frequency and

inter-RAT handover triggers areconsidered

CPICH Ec/N0 of serving cell

CPICH RSCP of serving cell

UE Tx power

RAN05 RRM

Enables full mobility with HSDPA




HSDPA flow control

• Ensures that BTS buffers have enough data for the transmission

needs• Prevent overflow in the BTS buffer to avoid discarded and

retransmitted data

• Ensures HSDPA capacity by filling the reserved power allocation

UE1

UE2

UE3

RNC buffer Node-B buffer

UE1

UE2

UE3

S c h e d u

l i n g




HSDPA shared control channelpower control

5-20% gain in cell throughput

• Power control method for the HS-SCCH (High-Speed Shared ControlChannel)

• Adjusts the HS-SCCH transmit power according to the required powerlevel at the UE

• Decreases the average power overhead required for this controlchannel (compared to using a fixed transmit power level for the HS-SCCH)

• Power is adjusted every TTI based on the CQI received from theUEs, as well as Ack/Nack/DTX received on the uplink HS-DPCCH forouter loop adjustments

• Estimated HSDPA cell throughput gain is 5%-20% (compared to usingfixed HS-SCCH power) depending on the environment and the totalpower allocated to HSDPA




HSDPA channel switching• The HSDPA channel switching

determines whether a user in a cell isallocated on the HS-DSCH or not

• Channel type selection decision is basedon several issues including

• UE capability

• cell resource availability

• UE handover status (active set size,IFHO/ISHO measurements)

• UE multi RAB configuration

PS channel typeselection in downlink

Selectionbetween

FACH and

DCH/HS-DSCH

Selectionbetween DCH

and HS-DSCH

Data transfer onFACH

Data transferon HS-DSCH

Data transfer onDCH

• Further in-activitydetection is used todetermine how long tokeep HS-DSCHreserved for a givenuser

RAN05 T l




HSDPA associated uplink DPCH schedulingHSDPA with high bit rate uplink

Uplink return channel scheduling

Enable bit rate up to 384 kbit/s in uplink

Sector info

PS: HS-DSCH(DL)

PS: DCH (UL)

- PS data up to 384 kbit/s in UL, HSDPA in DL

• Uplink return channel of approximately 64kbit/s for TCP acks (without headercompression) is required to support 1.8

Mbit/s sustained bit rate in DL over HSDPA• Operator selects maximum cell specific

datarate of 64, 128 or 384 kbit/s in uplink

• Similar functionalities are applied for theuplink return channel as is done with DCHwithout HSDPA in RAN05, includingreconfiguration to a smaller data rate incase of congestion or to make room for a

CS call (AMR/Video). Functionalities appliedare:

• RAB pre-emption (Other call may override)

• RT over NRT

• Decrease of the retried NRT DCH bit rate

• Enhanced priority based scheduling andoverload control

• Terminal may use the TFC selection tomomentarily use lower data rate due to e.g.power limitations or lack of data to betransmitted

RAN05 Telecom

HSDPA power allocation 50% headroom




HSDPA power allocation, 50% headroom

Common channels

A B

BTS Tx power Max power

PtxTarget

Semi-static HSDPA powerallocation

Event A:

•HSDPA UE entering the cell

or CELL_DCH•Power level belowPtxTarget_for_HSDPA_admit-> HSDPA is allocated

•cell specific parameter forHSDPA power

Event B:

•No HSDPA users inCELL_DCH state -> powerreleased-> release timer as parameter

•RT over NRT in case of non-controllable load exceedsPtxTarget_for HSDPA_admit

•Rel 99’ traffic exceedsPtxTarget_for_HSDPA_release, all MAC-d flows are relesedand the transmit powercontrol returned back toPtxTarget

R99 power reduced 30%from 13.3 W to 9.3 W

6W HSDPA power giveshigh bit rates

(4W from R99 and 2W from

headroom)

Power control headroom20W

9W

13W

15W

PtxTarget_for_HSDPA_admit

PtxTarget_for_HSDPA_release

Dedicated Channels




HSDSCHPriority = 1

Max power

Node-B Tx power• Event A: First MAC-d

flow entering the cell

PtxNC<=PtxtargetHSDPA-> HS-DSCH is selected,

otherwise DCHscheduling.

• When HSDPA power isin use: PtxNC target isPtxtarget. NRT DCHscheduling upto

PtxtargetHSDPA.• Event B:

PtxnonHSDPA>=PtxtargetHSDPA+PtxoffsetHSDP

A

- Overload controlactions for NRT DCH(s)

started• Event C:


A

- No more NRT DCHs,all MAC-d flows in the

A

Ptx_offset_HSDPAPtxnonHSDPA

PtxNC

Ptx_target_HSDPA

B

Ptxtotal

Ptx_target

C

PtxMaxHSDPA




HSDSCHPriority = 2

Max power

Node-B Tx power• Event A: First MAC-d

flow entering the cell

Ptxtotal<=PtxtargetHSDPA-> HS-DSCH is selected,

otherwise DCHscheduling.

• When HSDPA power isin use: PtxNC target isPtxtarget. NRT DCHscheduling upto

PtxtargetHSDPA.• Event B:


A

- All MAC-d flows in thecell released

• Event C: (normal NRTDCH overload control)

Ptxtotal>=Ptxtarget+Ptxoffset

- Overload controlactions for NRT DCH(s)started

A

Ptx_offset_HSDPA

PtxnonHSDPA

PtxNC

Ptx_target_HSDPA

B

Ptxtotal

Ptx_target

C

Ptx_offset

PtxMaxHSDPA




HSDPA RAN05 bit rate – cell shared with R99 DCH

1.8 Mbps closeto cell site

Approx 250 kbps atthe cell edge (G=-4dB) on HS-DSCH

Median data rate at0.7x distance

Assumptions:

-Total BTSpower 14W

-Orthogon.:1/(1+2.9d)

-Other cellsfully loaded




Assumptions:

• 5 spreading codes• Round Robin• 1 WSPC per cell

• DCH throughputw/o HSDPA 780kbit/s

• HSDPA+DCHthroughput1080kbit/s (HSDPA610kbit/s and DCH470kbit/s)

capacity gain~38%.

Cell Throughput – ITU Vehicular A Multipath




HSDPA BTS packet scheduler

• Packet scheduler similar to Round Robin principle is used for the MAC-hs

packets

• QoS requirements not considered

• Users are served in sequential order according to data availability

• Robust scheduler for achieving good cell throughput

• Improved in RAN06 with proportional fair packet scheduler




HSDPA transport with best effort AAL2 QoS

• All user plane traffic is carried on the same shared VCC

• Background HSDPA traffic is carried over ”Best Effort” AAL2 connections -> No capacity reservation on Iub forany single HSDPA mac-d flow

• Instead, Iub capacity can be reserved for the ”aggregate” of HSDPA users in the BTS.This allows an efficient sharing of Iub capacity amongst the HSDPA users

RNC

BTS

IubNew HSDPABearer

HSDPA

3GPP rel99Bearer

RNC mapsDCH traffic into AAL2s of

“default QoS”

RNC mapsHS-DSCH traffic into AAL2s

of“Best Effort QoS”

DCH traffic

HSDPA traffic

HSDPA reservation =max DCH usage whenHSDPA user present

HSDPA max overbookin

DCH only pipe

Shared pipe – DCH hstrict priority

HSDPA only pipe




Iub Efficiency with HSDPA

• HSDPA improves Iub efficiency compared to Release’99 packetdata since HSDPA is a time shared channel with a flow control inIub

• Release’99 requires dedicated resources from RNC to UE. Thoseresources are not fully utilized during TCP slow start or duringinactivity timer

• Additionally, HSDPA does not use soft handover no need forsoft handover overhead in Iub

= User 1

= User 2

= User 3

E1 for BTS1

E1 for BTS2

E1 for BTS11 2

1 = TCP slow start

2 = Inactivity timer

3

3 = Soft handover for some connections

Iub efficientlyutilized by HSDPA




Local management for HSDPA PM in BTS

HSDPA performance management

Node B3G SGSNRNC

Iub Iu-PS

BTS statistics•BTS buffer

measurements• CQI measurements

RNW statistics•non-HSDPA power

•Number of users distribution•HS-DSCH

allocations/durations/releases•RLC measurements

Transport statistics• AAL2 resources

RAN KPIs:•HSDPA availability•HSDPA throughput• Average number of HSDPA users•HSDPA Total Power




HSDPA handovers

1. HS-DSCH to HS-DSCH intra Node-B handover

2. HS-DSCH to HS-DSCH inter Node-B handover

3. HS-DSCH to DCH handover (needed if the UE is moving toa cell without HSDPA support)

Provide full intra-frequency mobility for HSDPA usersand enables HSDPA also in soft handover region

Cell with HSDPA capability

Cell without HSDPA capability

1

2 3

HSDPA Handover UL = soft and softer HO ; DL = Serving cellchange




HSDPA with additional RAB initiation

• HSDPA is suspended whenother RAB setup is initiated(e.g. Video call)

• Multicall combinations on

dedicated channels can beused

bit rate

HS-DSCH

time

DCH

Video call isinitiated ->HSDPA is

suspended

After HSDPA issuspended, DCH packetscheduling procedurescan be applied -> if stillenough data in buffer,

DCH is allocated

Enable multicalls for HSDPA users






HSDPA 16QAM support

QPSK

1/4


2/4

3/4

16

SF

16

16

16QAM2/4

3/4

16

16

1.2 Mbps


2.4 Mbps

3.6 Mbps4.8 Mbps

7.2 Mbps

1.8 Mbps


3.6 Mbps

5.3 Mbps7.2 Mbps

10.7 Mbps

600 kbps

Throughput(5 codes)

1.2 Mbps

1.8 Mbps2.4 Mbps

3.6 Mbps

• Node B can select 16QAM when channel quality is sufficient

• 16QAM will be typically be selected in 5-25% of the cell area,depending on the environment

• Average cell throughput increased by 5-20%

Peak data rates up to 3.6 Mbit/s5-20% gain in cell throughput

HSDPA

AMC

Frame SizeH-ARQ

Spreading& Multip.

RAN05.1 Telecom




HSDPA with 10 codes

QPSK

1/4


2/4

3/4

16

SF

16

16

16QAM2/4

3/4

16

16

1.2 Mbps


2.4 Mbps

3.6 Mbps

4.8 Mbps

7.2 Mbps

1.8 Mbps


3.6 Mbps

5.3 Mbps

7.2 Mbps

10.7 Mbps

600 kbps

Throughput(5 codes)

1.2 Mbps

1.8 Mbps

2.4 Mbps

3.6 Mbps

• High peak data rates, up to 7.2 Mbps

• High cell capacity

• Evolution of HSDPA with 5 codes and HSDPA with 16QAM -features

• Dynamic code allocation between 5 or 10 codes

• One HS-SCCH needed

Peak data rates up to 7.2 Mbit/s

HSDPA

AMC

Frame SizeH-ARQ

Spreading& Multip.




Results with HSDPA-only Traffic

HSDPA:920 kbps

HSDPA:940 kbps

HSDPA:1200 kbps

RAN05QPSK only

RAN05 RAN06

4% Gain

27%Gain

Due to using PFinstead of RR

HSDPA:960 kbps

HSDPA:1100 kbps

HSDPA:1500 kbps

RAN05QPSK only

RAN05 RAN06

14%Gain

36%GainDue to using PFinstead of RR

Due to 16QAM

Due to 16QAM

Vehicular-A Pedestrian-A

S f R lt ith Mi d HSDPA & DCH T ffi




Summary of Results with Mixed HSDPA & DCH Traffic

780 kbps

DCH:

410 kbps

1090 kbps

HSDPA:670 kbps

DCH:

410 kbps

1320 kbps

HSDPA:910 kbpsc

DCH:

780 kbps

HSDPA:N.A.

16QAM + RR 16QAM + PFNo HSDPA

4% Gain

21% Gain

Veh-A / Macrocell

Introducing HSDPAwith RR scheduler, 7

W HSDPA power


~1600* kbps

10 codes

*approx. from case ofHSDPA only trafficthroughput of 1800 kbps

21% Gain

DCH:

410 kbps

HSDPA:1190 kbps

DCH:

410 kbps

1055* kbps

HSDPA:635 kbps

QPSK + RR

39% Gain

Due to 16 QAMmodulation

Single user peak BR: 1.8 Mbps 3.6 Mbps 3.6 Mbps 7.2 Mbps

*approx. value, not directlyfrom simulations

RAN05.1 Telecom




HSDPA with 16 users per cellRoll out

• Maximum number of HSDPA users per BTS: 16

• HS-DSCH is transmitted to one cell at a time from the BTS

• Time multiplexed between different cells of the BTS

• Up to 3 cells per BTS can be enabled for HSDPA

Cell specific 1.8/3.6/7.2 Mbit/s HSDPA

(QPSK/16QAM)

HSDPA

AMC

Frame SizeH-ARQ

Spreading& Multip.

High capacity• Maximum number of HSDPA users per cell: 16

• HS-DSCH can be transmitted to all cells in the BTS at thesame time

• HSDPA with 16 users per cell brings the HSDPAperformance gains for each cell independently of the data

rate in the other cells in the same BTS• Availability of sufficient baseband processing and

transport resources required




HSDPA UE capability based handover

Cell (layer) with HSDPA capability

Cell (layer) without HSDPA capability

1 2

Enables multilayer support for HSDPA and maximumutilisation for HSDPA users when HSDPA is not

implemented on all frequency layers

• Load and service basedhandover (RAN05.1)feature is extended withthe following traffic

handling mechanisms:1. Direct HSDPA users to

the cell layer withHSDPA capability

2. Direct non-HSDPA usersto the layer without

HSDPA capability




HSDPA Proportional Fair packet scheduler

UE2



Data

Data

UE1

Multi-user selection diversity(give shared channel to “best” user)

TTI 1 TTI 2 TTI 3 TTI 4

USER 1 Es/N0USER 2 Es/N0

Scheduled user

BTS packet schedulingoperates at 2ms rate and

can utilize information onthe instantaneous channelconditions for each user(part of Nokia RAN06)




Fairness of Different Schedulers• Macro cell, Pedestrian-A, 3km/h, 50% Node-B power and 7 codes allocated

-5 0 5 10 15 200

50

100

150

200

250

300

350

FT

FR

M-TP

P-FR

User G- factor [dB]

A v e r a g e u s e r d a t a r a t e f o r 1 s i m u l a t i o n [ k b p s ]

20 users

Fair throughput

Fair resource

Proportionalfair (fast)

Max C/I (fast) • Slow schedulers

Fair resource

Fair throughput

• Fast schedulers

Proportional fair

Max C/I






0 0.2 0.4 0.6 0.8 10

500

1000

1500

2000

2500

3000

3500

4000

=

k b

p s

HSDPADCH

User Bit Rate in Macro Cell with 5-code HSDPA

3.6 Mbps closeto cell site

Approx 300 kbps atthe cell edge on HS-

DSCH

Median data rate770 kbps (with 0.7x

distance)

Average data rate1000 kbps

• HS-DSCH = 12W• DCH average = 3 W

• DCH SHO gain = 2 dB

HSDPA C ith Ad d T i l




0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10

1000

2000

3000

4000

5000

6000

7000

8000

Distance from BTS [relative to cell radius, 1=cell edge]

k b

p s

10-code, 2-eq

10-code, 1-eq5-code, Rake

HSDPA Coverage with Advanced Terminals

7.2 Mbps onlyclose to cell site

350-700 kbpsat the cell edge

Average data rateover cell area 1000-

2500 kbps

Single user assumed on HS-DSCH



C ll Th h t R lt R d R bi




Cell Throughput Results Round Robin

If the goal is to maximizethe total cell throughput,then the HSDPA powershould be fixed at 7-8 Watt,resulting in a total cellthroughput of 1150 kbps.

Without any HSDPA traffic,

theRel’99 DCH cell capacityequals780 kbps.

Thus, using 7-8 Watt forHSDPA and 5 HS-PDSCH

codes, the total cellthroughput is increased bya factor 1150/780=1.47

Cell Throughput Results for Proportional Fair




g p p

If the goal is to maximizethe total cell throughput,

then the HSDPA powershould be fixed at 7-8 Watt,resulting in a total cellthroughput of 1320 kbps.

Without any HSDPA traffictheRel’99 DCH cell capacityequals780 kbps.

Thus, using 7-8 Watt forHSDPA and 5 HS-PDSCHcodes, the total cellthroughput is increased by

a factor 1320/780=1.69.






Results with HSDPA-only Traffic

HSDPA:920 kbps

HSDPA:940 kbps

HSDPA:1200 kbps

RAN05QPSK only

RAN05 RAN06

4% Gain

27%Gain


HSDPA:960 kbps

HSDPA:1100 kbps

HSDPA:1500 kbps

RAN05QPSK only

RAN05 RAN06

14%Gain

36%GainDue to using PF

instead of RR

Due to 16QAM

Due to 16QAM

Vehicular-A Pedestrian-A

Summary of Results with Mixed HSDPA & DCH Traffic




y

780 kbps

DCH:

410 kbps

1090 kbps

HSDPA:670 kbps

DCH:

410 kbps

1320 kbps

HSDPA:910 kbpsc

DCH:

780 kbps

HSDPA:N.A.

16QAM + RR 16QAM + PFNo HSDPA

4% Gain

21% Gain

Veh-A / Macrocell

Introducing HSDPAwith RR scheduler, 7

W HSDPA power

Due to using PF

instead of RR

~1600* kbps

10 codes

*approx. from case ofHSDPA only trafficthroughput of 1800 kbps

21% Gain

DCH:

410 kbps

HSDPA:1190 kbps

DCH:

410 kbps

1055* kbps

HSDPA:635 kbps

QPSK + RR

39% Gain

Due to 16 QAMmodulation

Single user peak BR: 1.8 Mbps 3.6 Mbps 3.6 Mbps 7.2 Mbps

*approx. value, not directlyfrom simulations






HSDPA Cell Throughput

0

1000

2000

3000

4000

5000

6000

Macro cell Small cell

WCDMA R99

HSDPA simple scheduler

HSDPA advanced scheduler

HSDPA advanced mobiles

WCDMA R99 = WCDMA Release 99 dedicated channelHSDPA simple scheduler = HSDPA with round robin schedulerHSDPA advanced scheduler = HSDPA with proportional fair scheduler

HSDPA advanced mobiles = HSDPA terminals with rx diversity and equalizer

Gain from Advanced UEs




Gain from Advanced UEs

Median data rate gain from advanced terminals in macro

cells

0%

20%

40%

60%

80%

100%

120%

140%

5 codes 10 codes 15 codes

Low power

High power

• Advanced UE = 2 branch receiver + equalizer• 2 branch gain assumed 2.5 dB in Es/N0• Equalizer improves orthogonality from 0.2-0.9 to 0.8-0.95

Round Trip Time Evolution




Round Trip Time EvolutionNo Queuing Time Due to Loading Included

Round trip time of 32-B packet

0

20

40

60

80

100

120

140

160

180

200

RAN1.5ED2 RAN04 (20-ms

TTI)

RAN04 (10-ms

TTI)

RAN05 HSDPA HSDPA+HSUPA

(2-ms TTI)

m s

Internet

Iu + core

RNC

Iub

Node B

AI

UE

Release 99<150 ms

HSDPA<100 ms

HSUPA50 ms

Documents

Hsdpa Training