04 UMTS HSDPA Technology-55

HSDPA Technology

ZTE University

Driver to HSDPA

HSDPA Theory

HSDPA Algorithm

HSDPA Solution

Content

Competition to operator

Introduce HSDPA Introduce HSDPA to WCDMAto WCDMA

2.5G GPRS: 9.05 -

171.2kbit/s, Service deployment is bad

CDMA2000 1x: 153.6kbit/s, Service deployment is good3G

CDMA 1x EV-DO: 2.4Mbit/sWCDMA R99/R4: 2Mbit/s

Peak data rate (Kbps)Mean data rate (Kbps)

R99

The driver to HSDPA

HSDPA is a new technology to enhance WCDMA PS data service HSDPA gives subscribers new experience of higher speed

data service with shorter time delay HSDPA brings more bandwidth and more online subscribers It is necessary and feasible to introduce HSDPA to WCDMA

network With consideration of network planning and deployment

cost, HSDPA should be applied at the beginning, or at least the Node B should hardware ready for HSDPA

HSDPA brings new requirement of transmission and network planning. Pay more attention to it.

HSDPA, Mature technology2002.6 R5 released2003.6 HSDPA (High Speed Downlink Packet Access) was

added into R5

HSDPA is smoothly evolved from WCDMA R99 without any big effect to the existing R99 network

1 new transport channel: HS-DSCH 3 new physical channels： HS-PDSCH, HS-SCCH and HS-DPCCH MAC-hs sub-layer, HARQ (Fast Hybrid Automatic Repeat ReQuest),

Fast Scheduling and AMC (Adaptive Modulation and Coding)

HSDPA --Max. downlink data rate: 14.4Mbps

Competition advantage of HSDPA

Standard Data rate (Mbps) Subscribers per cell

WCDMA R99/R4 231×PS64k, 15×PS128k or

7×PS384k(SF=32, SF=16 or SF=8)

HSDPA 14.464

(117.7kbps per user, SF=16, R=3/4, 16QAM)

CDMA2000 1x EV-DO 2.4

59 (only tens of kbps, 200kbps when 8 users is configured)

HSDPA supports more users while provides higher data rate!

Driver to HSDPA

HSDPA Theory

HSDPA Algorithm

HSDPA Solution

Content

Evolve from R99/R4 to HSDPA

L2

L1

DSCH FP

RLC

L2

L1

DSCH FP

Iub/ Iur

PHY

M AC

PHY

RLC

Uu

M AC-d

HS-DSCHFP

HS-DSCHFP

MAC-hs

PHY(add 3

channels)

RNC, Node B: add HS-DSCH FP protocol process, involve Iub/Iur Node B: add MAC-hs, responsible for AMC, HARQ, etc. Node B: add 3 physical channels: HS-PDSCH,HS-SCCH,HS-DPCCHUE: add MAC-hs, physical channels and process, modulation

MAC(add

MAC-hs)

PHY(add

process)

UE UTRAN

New physical channels of HSDPA

HS-PDSCH is the bearer of HS-DSCH, transfer HSDPA user data (downlink) 2ms TTI, 3 slots, spread factor is fixed to 16, multiple users & multiple codes, modulation method: QPSK and 16QAM

HS-SCCH bears information of HS-DSCH such as UE specialized mask code, modulation and coding policy, etc. (downlink) 2ms TTI, 3 slots, spread factor is fixed to 128

HS-DPCCH bears feedback information of HS-PDSCH such as Channel Quality Indication (CQI), H-ARQ confirm information ACK/NACK, etc. (uplink) 2ms TTI, 3 slots, spread factor is fixed to 256

H S-DPCCH

H S-PDSCHHS-SCCH

UE

DPCH

DCCH＋UL DTCH

DL DTCH

CN UTRAN

R99 channelHSDPA channel

HSDPA working procedure

RNCNode B(AMC and HARQ)

Data Packet

⑤ACK/N

ACK （

HS-DPC

CH）

⑥Data

packet

+ re-

send (

if

need)

(HS-DS

CH)

AMC, modulation and coding selection

HARQ, lowers the time delay, improves the data throughput

Fast scheduling, quick decision

①CQI（

HS-DPC

CH）

③HS-DS

CH par

ameter

s (HS-

SCCH)

Data

(HS-DS

CH)

②Evaluation, HS-DSCH parameters setting

④Receive data from HS-DSCH according to Detecting HS-SCCH

Key technology: AMC (1)

Adaptive Modulation and Coding (AMC), Node B can adjust modulation (QPSK, 16QAM) and coding rate (1/3, 3/4, etc) in time according to the feedback channel state from UE. So data transferring can follow the step of channel state changing in time, it is a good technology for link self-adaptive

For long time delay packet data, AMC can improve system capacity without add interference to neighbor cells

Standard AMC Remark

R99/R4 N Quick power control

HSDPA Y Satisfy 15dB SIR dynamic range


Node BNode B

CQI (Report CQI (Report periodically)periodically)

Modulation (QPSK, 16QAM) self-adaptiveGood channel state: 16QAMBad channel state: QPSK

Coding rate (1/3, 3/4, etc.) self-adaptiveGood channel state: 3/4Bad channel state: 1/3

Efficiently utilize the channel condition

Good channel state: higher speedBad channel state: lower speed

Codes adjustingGood channel state: more codesBad channel state: fewer codes


Standard Data rate (kbps)

SF Modulation Coding rate

R99/R4 384 8 QPSK 1/3HSDPA 720 16 16QAM 3/4

HSDPA, the service bearing ability of one channel is further larger than R99/R4 by using more efficient modulation and coding rate, while SF is twice as R99/R4

As using bigger SF, system can support more users

HSDPA, R99/R4 channel bearing ability comparison


Modulation coding rate

Data rate (1 code)

Data rate (5 codes)

Data rate (15 codes)

QPSK 1/4 120kbps 600kbps 1.8Mbps

QPSK 1/2 240kbps 1.2Mbps 3.6Mbps

QPSK 3/4 360kbps 1.8Mbps 5.4Mbps

16QAM 1/2 480kbps 2.4Mbps 7.2Mbps

16QAM 3/4 720kbps 3.6Mbps 10.8Mbps

HSDPA throughput, relative with modulation & coding rate

HSDPA can provide data rate per user up to 10.8Mbps (16QAM, 3/4) by AMC and multiple codes technology

In the situation of high speed, HSDPA requires high channel condition

Key technology: HARQ (1)

Hybrid Automatic Repeat reQuest (HARQ) is a combined technology with Forward Error Correction (FEC) and Automatic Repeat reQuest (ARQ)

HARQ can provide flexible and subtle adjustment for its process by cooperated with AMC

Standard HARQ Remark

R99/R4 NFEC is in high layerARQ is in RLC layer, channel feedback is slow

HSDPA Y Includes physical layer HARQ and HARQ entity in MAC-hs

L1 HARQ

HARQ

MAC-hs

TFRC

L1L2

Key technology: HARQ (2)Advantage: improve transferring reliabilityDisadvantage: lower utilization in bad channel state

Advantage: good performance in lower Bit Error Rate (BER)Disadvantage: bad performance in high BER

FECARQ

HARQ

Combine FEC and ARQ, each sending packet includes error detection bit and error correction bit

Packet

A con

firm

Packet

A con

firm

Error packet A

Packet A

Packet A

Error packet A

Packet A

Packet A missing data

Packet A missing data

HARQ phase I（ Resending is in RNC， R99）

HARQ phase II, III（ Resending is in Node B, HSDPA）

Packet A

Discard ReserveResend

whole packet Resend data

Soft combination

Resend

requi

rement

Resend

requi

rement

Packet B

Packet B

Send SendReceive Receive

Lower efficiencyLonger time delay

Higher efficiencyShorter time delay

Key technology: Quick scheduling (1)

With quick channel feedback, HSDPA can suitably adjust coding rate, codes, modulation, etc. in time according to the channel state

Standard

TTI (ms)

Channel feedback time delay (ms)

Remark

R99 10 100 (at least)

HSDPA 2 5.67Supports continuous feedback, R5 also supports 10ms TTI

HS-PDSCH

HS-SCCH

HS-DPCCH (ACK/NACK and CQI)

HS-SCCH

2 TS 7.5 TS +/- 128 Chip N TS

1 TS = 2560 Chip HSDPA channel feedback time delay is about 8.5 TS

Quick channel feedback

Driver to HSDPA

HSDPA Theory

HSDPA Algorithm

HSDPA Solution

Content

Scheduling Algorithm

The main aim is to calculate the relative priority of all UEs in each TTI of 2ms according to preset algorithm, and sort them. The UE with higher priority will be scheduled first.

The scheduling algorithms implemented by ZTE UMTS Node B include Max-C/I, Round robin(RR) and Proportional fair(PF).

The parameter “Scheduling Algorithm” is used to set the algorithm in cell level.

RR Algorithm

The relative priority of RR algorithm is given by:

Relative Priority = Current Time – Last Time of UE Scheduling

The unit of time in the above equation is TTI 2ms.

Current Time: Refers to current scheduling time.

It is obvious that RR algorithm has the longest scheduling waiting time.

MAX C/I Algorithm The MAX C/I algorithm only takes into account the

channel quality to maximize cell throughput. The relative priority of MAX C/I algorithm is given by:Relative Priority = CQI × TBSIZE

The Channel Quality Indicator (CQI) is fed back by HS-DPCCH of UE. The maximum MAC-hs Transmission Block Size (TBS) of UE is obtained by querying the CQI mapping table for UE categories provided by TS 25.214 based on current CQI, UE categories and number of available HS-PDSCH channelization codes.

PF Algorithm PF algorithm takes into account both the channel

quality and history traffic, or both cell throughput and user fairness. As a tradeoff between fairness and cell throughput. The relative priority of PF algorithm is given by:Relative Priority = (Weight of SPI ×Weight of CQI × TBS) ÷ (1 + History Traffic)

The Schedule Priority Indicator (SPI) refers to the UE scheduling priority, which ranges between 0 and 15. The SPI is related to the UE services. Weight of SPI refers to the weight obtained through SPI mapping which is configured through the parameter SPI Factor(SPI Factor). The larger the value of SPI Factor , the steeper the mapping relation between Weight of SPI and SPI, that is, the more scheduling chance the UEs with high SPI have.

PF Algorithm Weight of CQI refers to the weight obtained through CQI mapping

which is configured through the parameter Channel Quality Weight. The larger the value, the steeper the mapping relation between Weight of CQI and CQI, that is, the more scheduling chance the UEs with high CQI have.

The history traffic of UE attenuates at a rate of 4% at intervals of 2 ms, and the accumulated newly transmitted data increases by TBS, as given in the following equation:History Traffic(n) = History Traffic (n-1) * 0.96 + TBS

Where, TBSIZE is a variable because the data volume scheduled each time varies. n refers to the times of history scheduling. History Flux(n) refers to the history flux after n times of scheduling. TBSIZE refers to the TBSIZE of last scheduling. Under an ideal situation: If data is scheduled every 2 ms, TBSIZE in each scheduling is unchanged andn is sufficiently large, then History Flux will converge at about 25 times the value of TBSIZE instead of being an infinitive value.

Summary of Scheduling Algorithms

The MAX C/I algorithm focuses on the maximum cell throughput, but is seldom adopted in practice.

The PF algorithm is the most widely used and complicated scheduling algorithm, and also has the best comprehensive effect.

The RR algorithm is rather simple and generally adopted for comparison test with the PF algorithm.

HSDPA Code Resource

OVSF Code Tree

The previous figure shows the downlink OVSF code tree: some have been allocated to the common channels. Each channel code is represented by C (m, n), m is the spreading frequency, n is the channel code number, 0≤n≤m-1, m is 2n.

HSDPA cells need to configure common channels and its channel codes is similar to R99 cells. Codes of P-CPICH and P-CCPCH are set to be (256, 0); S-CCPCH number and SF (256~4) are changeable.

HSDPA Channel Code Allocation When configuring the channel of the HSDPA cells,

besides the common channels similar to R99, code resources shall be allocated to HS-SCCH (static configuration) and HS-PDSCH if statically allocating the code resources. SF of HS-SCCH is set to 128, and that of HS-PDSCH is set to 16. In this case R99 subscribers can’t use the code resources of HSDPA.

If code resources are dynamically allocated, OMC-R will define initial HS-DSCH, the minimum HS-DSCH and the maximum HS-DSCH. Code resources occupied by HSDPA subscribers is not the maximum and the minimum, if more R99 CS subscribers want to get accessed, HSDPA code resources can be occupied.

• Blue color: R99 codes• Red color: HSDPA codes

SF=16

SF=16

HSDPA Dynamic Code Allocation Methods

Code Resources Allocation of HSDPA A-DPCHs

If a subscriber requests a fast-speed PS service, it will be born on HSDPA. HS-SCCH, HS-PDSCH will be occupied, and a DCH (A-DPCH) will be allocated for signaling transmission. A-DPCH is born on 3.4k rate and a downlink dedicated channel with SF256 will be occupied.

HSDPA Power Allocation Methods

• In case of dynamic HSDPA power, margin power normally is about 2%.

Dynamic HSDPA power

Static HSDPA power

HSDPA Power Configuration

The allocation of HSDPA power is divided into dynamic configuration and static configuration.

Dynamic configuration: HSDPA available power=cell power * (1- power margin) -the power of R99 traffic channels and of common channels. In this case, power can be dynamically allocated between R99 subscribers and HSDPA subscribers. R99 CS traffic has real-time requirements, has the priority and can occupy HSDPA power if necessary.

Static configuration: HSDPA power is allocated and fixed. In this case, the power of R99 and HSDPA is independent and can’t be occupied between.

HS-PDSCH Power Control Two types of HS-PDSCH power control algorithms

are provided. The parameter is HS-DSCH Power Control Algorithm Type. The One is the average power control algorithm, the average available power of all UEs that can be scheduled in one TTI. The other is MPO power control algorithm.PHS-PDSCH = PCPICH+MPO+Δ

PCPICH: Refers to the receive power of pilot channel.

MPO: refers to the Measurement Power Offset. Δ Reference Power Adjustment obtained after

querying the CQI mapping table for UE categories.

HS-SCCH Power Control

The configuration of HS-SCCH power can either be static or dynamic. Static configuration has little flexibility, it means transmitting fixed power without considering the change of the channel condition, which will lead to the power waste when channel condition is favorable and the inadequate power when channel condition is bad. Dynamic power configuration means the power can be transmitted flexibly according to the channel condition.

HSDPA Mobility Sample

Intra Frequency Relations (idle+connected mode)

UMTS F1

UMTS F2

UMTS F1

Load Balance relations (connected mode)

Inter-frequency Mobility (idle+connected mode)

Cell reselection (idle mode)

(R99+HSDPA)

(R99)

2G

2G

UMTS F2

Inter-RAT Mobility (idle+connected mode)

HS-PDSCH Intra-frequency Handover

1. M easurem ent Report (1d)

2. Decide to Change HS-DSCH

Serving Cell3. Radio Link Reconfiguration Prepare

5. Radio Link Reconfiguration Ready

4. Radio Link Reconfiguration Prepare


7. Radio Link Reconfiguration Com m it8. Radio Link Reconfiguration Com m it

9. Physical Channel Reconfiguration10. Physical Channel Reconfiguration Com plete

Source Serving Node B

Target Serving Node B RNCUE

HSDPA→DCH Handover

1. M easurem ent Report (e.g. 1D)

2. Decide HS-DSCHà DCH





7. Radio Link Reconfiguration Com m it8. Radio Link Reconfiguration Com m it

9. Transport Channel Reconfiguration10. Transport Channel Reconfiguration Com plete

Serving Node B

Non-Serving Node B RNCUE

DCH → HSDPA Handover

1. M easurem ent Report (e.g. 1D)

2. Decide DCHà HS-DSCH

7. Radio Link Delete Request8. Radio Link Delete Response

3. Radio Link Setup Request4. Radio Link Setup Response

5. Transport Channel Reconfiguration6. Transport Channel Reconfiguration Com plete

Source Node B

Target Serving Node B RNCUE

Driver to HSDPA

HSDPA Theory

HSDPA Algorithm

HSDPA Solution

Content

Combination of HSDPA and R99/R4

HSDPA makes the balance between the coverage and the throughput, increase the coverage decrease the throughput.

HSDPA provides about 200kbps in the edge of cell, Less than the R99/R4 DCH.

Recommend to combine the HSDPA and R99/R4 DCH together, at the edge of cell UE can “handover” into DCH. With this combination, you can take the most advantage from R99/R4 and HSDPA.

0 10 20 30 40 50 60 70 80 90 1000

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000DL

Capabi

lity (

kbps)

distance/cell_radius %

R99 PSHSDPA


-2 0 2 4 6 8 10 12 14 160

5

10

15Nu

m of H

SDPA

user

Available Num of SF16 for HSDPA

-2 0 2 4 6 8 10 12 14 160

50

100

150

Available Num of SF16 for HSDPA

Num of R

99 user


0 2 4 6 8 10 12 14 16 18 200

1

2

3

4

5

6

Cell H

sdpa

Tho

ughp

ut M

bit/s

HSDPA User Num

5 codes HSDPA only10 codes HSDPA only15 codes HSDPA only


-13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -330

40

50

60

70

80

90

100R99 Capability Loss

R99 Us

er Num

Percent %

Total HSDPA Power offset to BsTxPwer (dB)

HSDPA heavy loadHSDPA light load


-13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -330

40

50

60

70

80

90

100R99 Capability Loss

R99 Us

er Num

Percent %

Total HSDPA Power offset to BsTxPwer (dB)

HSDPA heavy loadHSDPA light load

1 2 3 4 5 6 7 81.5

2

2.5

3

3.5

4

4.5

5

5.5

6

6.5

SectorThroughput M

bit/s

User Num

R99 N/AR99 36dBmR99 38dBmR99 40dBm

HSDPA


10 20 30 40 50 60 70 80 90 100 1100

1

2

3

4

5

6Throughput Mbit/s

R99 12.2k User Num

R99 ThroughputHsdpa ThroughputCell Throughput

ZTE HSDPA construction solution

If necessary, use a carrier

only to support PS

data

Network construction

plan

Frequency point assignment

Resource condition Advantage and disadvantage

Recommended deployment

Intra-frequency plan

F1: HSDPA+R99/R4 Less inter-frequency handover, admission control, load control and power control can be achieved within one same frequency cell.

Advantage: easy to do resource control

Disadvantage: do not have user detail classification

After the network construction finished, to achieve the high demand of voice and PS downlink.

F2: HSDPA+R99/R4

Inter-frequency plan

F1: R99/R4

Situation I: if HSDPA frequency point support normal handset, all the resource have to be assigned within various different frequency cells.

Situation II: HSDPA frequency point are only used for PC card, resource management can be achieved more easily.

Advantage: voice user +HSDPA users get good service

Disadvantage: resource control will be difficult in situation I, maybe some frequency point resource will be wasted at the beginning

With the development of 3G, to provide dedicated frequency point for HSDPA PC card (only PS domain)

F2: HSDPA

HSDPA(PC card)

f1 f2 f3R99/R4+HSDPA

R99/R4+HSDPA

Phase I, IIPhase III

ZTE solution

HSDPA construction areaPhase I :several hot spot,and the important building to deploy HSDPA

Phase II :all the hot spot and several macro sites to deploy HSDPA

Handover between HSDPA and R99/R4handover policy

motivation description

Handover based on traffic load

The traffic load for HSDPA and R99/R4 has large difference. Then we trigger the handover

trigger handover while the traffic load of HSDPA cell is too heavy and the load of R99/R4 cell is lower, or the traffic load of different HSDPA cells are not in balance

Handover based on service

According to the service type and data rate to choose HSDPA or R99/R4 network

Low speed data service can be handled with FACH, Streaming service can be handled with DCH; the rest high speed PS data service or non-real time data service should be assigned to HSDPA

Handover between HSDPA, R99/R4 and DCH/FACH channels，can guarantee the service stability of HSDPA

Network analysis for HSDPA and R99/R4

After the 3G network construction, the basic demand of WCDMA network should adopt HSDPA function, with soft smooth upgrade ability

HSDPA is not constructed as a individual network, HSDPA is a enhanced technology of WCDMA (throughput, users)

Network construction and plan for R99 and HSDPA based on the “one-shot planning, multi-stage deployment”

HSDPA and R99 share the same network, Node B supports HSDPA function

At dense traffic area (capacity is restricted), HSDPA can share the same site of R99 and achieve the same coverage of it.

Capacity and coverage is a balance relationship, increase the network performance to the maximum by making a balance between them.

HSDPA for major areaArea type Square (km2) Erl

Dense urban 91.5 3527

Urban 179.78 4873

Suburb 3000.5 2100

total 3271.78 10500

Major area have no more

than 10% proportion

Major area

occupy 80%

traffic

Fully HSDPA coverage for major area!

Major area： dense urban + urbanDense urban

UrbanSuburb

HSDPA outdoor coverage

Node BNode B

Adaptive modulationGood channel state: 16QAMAdaptive coding rateGood channel state: 3/4

AMC

HSDPA requires a good channel condition for high speed service: Good channel state Near to Node B

At beginning, HSDPA is suitable for micro Node B coverage of outdoor hotspot

Micro Node B is more suitable for HSDPA

HSDPA indoor coverageHSDPA indoor

coverage CBD (focus on) Office, hotel, etc Shopping center, airport,

etc

Macro Node B＋ Indoor distributed system Macro Node B/base band pool＋RRU＋ Indoor distributed system Micro Node B＋ Indoor distributed system Pico

Solution

Transmission

Pico

RRU

Power distribu

tor

Twisted

pair

Fiber

Feeder

Macro Node B or base band

pool

Concern of HSDPA indoor coverage Is the existing indoor

distributed system of R99/R4 suitable for HSDPA?

Is capacity of the existing indoor distributed system enough？ Is the transmission enough?

the indices of indoor distributed components (like power distributor) required by HSDPA and R99 are same,

So the existing indoor distributed system of R99/R4 is suitable for HSDPA

Number of sites (S111)

Site radius

Existing R99 planning

52 537m

Existing R99 sites

HSDPA planning NE Cost of NE Total cost

Advantage

Planning the same number of

sites as R99/R4

CN Same

Add 8％The capacity of PS increases 80 ~120

％

RNC Add 5％Node B Add 10％

Planning Area: 30km2 Subscribers: 80000

HSDPA network planning case study

For capacity R99 cell peak data rate:

7×384Kbps=2.688Mbps HSDPA cell peak data rate:

15×960Kbps×3/4 = 10.8 Mbps Peak throughput of HSDPA

cell is 4 times as that of

R99 cell

For traffic mode The PS traffic mode will

change greatly, more PS traffic will rush into HSDPA system

Peak throughput of HSDPA cell is 4 times as that of R99 cell, and

mean throughput of HSDPA cell is 2 times as that of R99 cell

Consider both capacity and traffic mode, transmission resource of Iub

at beginning should be reserved 4 times as before or at least 2 times

HSDPA requires more transmission resource, because of the changing of capacity of Node B and traffic mode

HSDPA transmission solution

Control

HSDPA Processor

DL Coder

DL Base-band

HSDPA Processor

UL Decoder

UL Base-band

Mid-frequency

After HSDPA Update

Before HSDPA Update

After HSDPA Update

Before HSDPA Update

Iub Interface

Features Advanced design， HSDPA

functions have been embedded into hardware.

Just update software to support HSDPA functions.

No additional hardware is needed!

ZTE serialized Node B support HSDPA flexible update

04 UMTS HSDPA Technology-55

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Transcript of 04 UMTS HSDPA Technology-55