04 Umts Hsdpa Technology-55

7/26/2019 04 Umts Hsdpa Technology-55

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HSDPA Technology

ZTE University


2/54

Driver to HSDPA

HSDPA Theory

HSDPA Algorithm

HSDPA Solution

Content


3/54

Competition to operator

Introduce HSDPA

to WCDMA

2.5G GPRS: 9.05 -171.2kbit/s,

Service deployment is bad

CDMA2000 1x: 153.6kbit/s,

Service deployment is good

3G

CDMA 1x EV-DO: 2.4Mbit/s

WCDMA R99/R4: 2Mbit/s

Peak data rate (Kbps)

Mean data rate (Kbps)

R99


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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.


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HSDPA, Mature technology

2002.6 R5 released

2003.6 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 channelsHS-PDSCH, HS-SCCH and HS-DPCCH

MAC-hs sub-layer, HARQ (Fast Hybrid Automatic Repeat ReQuest), FastScheduling and AMC (Adaptive Modulation and Coding)

HSDPA --Max. downlink data rate: 14.4Mbps


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Competition advantage of HSDPA

Standard Data rate (Mbps) Subscribers per cell

WCDMA R99/R4 231PS64k, 15PS128k or 7PS384k

(SF=32, SF=16 or SF=8)

HSDPA 14.4

64

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

16QAM)

CDMA2000 1x EV-

DO2.4

59

(only tens of kbps, 200kbps when 8

users is configured)

HSDPA suppo rts more users whi le provides hig her data rate!


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Driver to HSDPA

HSDPA Theory

HSDPA Algorithm

HSDPA Solution

Content


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Evolve from R99/R4 to HSDPA

L2

L1

DSCH

FP

RLC

L2

L1

DSCH

FP

Iub/ Iur

PHY

MAC

PHY

RLC

Uu

MAC-d

HS-DSCH

FP

HS-DSCH

FP

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-DPCCH

UE: add MAC-hs, physical channels and process, modulation

MAC

(add

MAC-hs)

PHY

(add

process)

UE UTRAN


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New physical channels of HSDPA

HS-PDSCHis 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

HS-DPCCH

HS-PDSCH

HS-SCCH

UE

DPCH

DCCHUL DTCH

DL DTCH

CN UTRAN

R99 channel

HSDPA channel


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HSDPA working procedure

RNCNode B

(AMC and HARQ)

Data Packet

AMC, modulation and coding selection

HARQ, lowers the time delay, improves the

data throughput

Fast scheduling, quick decision

Evaluation, HS-DSCH parameters setting

Receive data from HS-DSCHaccording to DetectingHS-SCCH


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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


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Node B

CQI (Report periodically)

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

Bad channel state: QPSK

Coding rate (1/3, 3/4, etc.) self-adaptive

Good channel state: 3/4

Bad channel state: 1/3

Efficiently utilize the channel condition

Good channel state: higher speed

Bad channel state: lower speed

Codes adjusting

Good channel state: more codes

Bad channel state: fewer codes


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Standard Data rate (kbps) SF Modulation Coding rate

R99/R4 384 8 QPSK 1/3

HSDPA 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


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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


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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 layer

ARQ 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

L1

L2


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Key technology: HARQ (2)

Advantage: improve transferring reliability

Disadvantage: lower utilization in badchannel state

Advantage: good performance in

lower Bit Error Rate (BER)

Disadvantage: bad performance in

high BER

F

EC

A

R

Q

HA

R

Q

Combine FEC and ARQ, each

sending packet includes error

detection bit and error correction bit

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 Reserve

Resend

whole packet Resend data

Soft

combinationPacket BPacket B

Send SendReceive Receive

Lower efficiency

Longer time delay

Higher efficiency

Shorter time delay


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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 feedbacktime delay (ms)

Remark

R99 10 100 (at least)

HSDPA 2 5.67

Supports 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 ChipHSDPA channel

feedback time delay

is about 8.5 TS

Quick channel feedback


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Driver to HSDPA

HSDPA Theory

HSDPA Algorithm

HSDPA Solution

Content


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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 setthe algorithm in cell level.


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RR Algorithm

The relative priority of RR algorithm is given by:

Relative Priority = Current TimeLast 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.


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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-DPCCHof 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 channelizationcodes.


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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.


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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.


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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 thebest comprehensive effect.

The RR algorithm is rather simple and generally

adopted for comparison test with the PF algorithm.


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HSDPA Code Resource


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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,

0nm-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.


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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 cant 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.


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Blue color: R99 codes

Red color: HSDPA codes

SF=16

SF=16

HSDPA Dynamic Code Allocation Methods


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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 3.4krate and a downlink dedicated channel with SF256

will be occupied.


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HSDPA Power Allocation Methods

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

Dynamic HSDPA power Static HSDPA power


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HSDPA Power Configuration

The allocation of HSDPA power is divided into dynamicconfiguration 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 subscribersand 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 cant be occupied between.


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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.P

HS-PDSCH= P

CPICH+MPO+

PCPICH: Refers to the receive power of pilot channel.

MPO: refers to the Measurement Power Offset.

Reference Power Adjustment obtained after querying the

CQI mapping table for UE categories.


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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.


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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)


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HS-PDSCH Intra-frequency Handover

1. Measurement Report (1d)

2. Decide to

Change HS-DSCH

Serving Cell

3. Radio Link Reconfiguration Prepare

5. Radio Link Reconfiguration Ready



7. Radio Link Reconfiguration Commit8. Radio Link Reconfiguration Commit

9. Physical Channel Reconfiguration

10. Physical Channel Reconfiguration Complete

Source ServingNode B

Target ServingNode B

RNCUE


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HSDPADCH Handover

1. Measurement Report (e.g. 1D)

2. Decide

HS-DSCHDCH





7. Radio Link Reconfiguration Commit8. Radio Link Reconfiguration Commit

9. Transport Channel Reconfiguration

10. Transport Channel Reconfiguration Complete

ServingNode BNon-ServingNode B RNCUE


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DCHHSDPA Handover

1. Measurement Report (e.g. 1D)

2. Decide

DCHHS-DSCH

7. Radio Link Delete Request

8. Radio Link Delete Response

3. Radio Link Setup Request

4. Radio Link Setup Response

5. Transport Channel Reconfiguration

6. Transport Channel Reconfiguration Complete

SourceNode BTarget ServingNode B RNCUE


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Driver to HSDPA

HSDPA Theory

HSDPA Algorithm

HSDPA Solution

Content


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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

10000

DL

C

apability

(kbps)

distance/cell_radius %

R99 PS

HSDPA


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-2 0 2 4 6 8 10 12 14 160

5

10

15

Num

ofHSDPAuser

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

ofR99user


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0 2 4 6 8 10 12 14 16 18 200

1

2

3

4

5

6

CellHsdpaThoughpu

tMbit/s

HSDPA User Num

5 codes HSDPA only

10 codes HSDPA only

15 codes HSDPA only


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

40

50

60

70

80

90

100R99 Capability Loss

R99UserNum

Percent%

Total HSDPA Power offset to BsTxPwer (dB)

HSDPA heavy load

HSDPA light load


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

40

50

60

70

80

90

100R99 Capability Loss

R99UserNum

Percen

t%

Total HSDPA Power offset to BsTxPwer (dB)

HSDPA heavy load

HSDPA 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

SectorThroughputMb

it/s

User Num

R99 N/A

R99 36dBm

R99 38dBm

R99 40dBm

HSDPA


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10 20 30 40 50 60 70 80 90 100 1100

1

2

3

4

5

6

ThroughputMbit/s

R99 12.2k User Num

R99 Throughput

Hsdpa Throughput

Cell Throughput


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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 doresource control

Disadvantage: do not

have user detail

classification

After the networkconstruction 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: resourcecontrol 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 f3

R99/R4+

HSDPA

R99/R4+

HSDPA

Phase I, IIhase III

ZTE solution

HSDPA construction area

Phase I :several hot spot,

and the important building

to deploy HSDPA

Phase II :all the hot spot and

several macro sites to deploy HSDPA


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Handover between HSDPA and R99/R4

handover

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 basedon service

According to the servicetype and data rate to

choose HSDPA or

R99/R4 network

Low speed data service can be handledwith 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


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Network analysis for HSDPA and R99/R4

After the 3G network construction, the basic demand of WCDMA networkshould 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.


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HSDPA for major area

Area type Square (km2) Erl

Dense urban 91.5 3527

Urban 179.78 4873

Suburb 3000.5 2100

total 3271.78 10500

Major area haveno more than

10% proportion

Major area

occupy

80% traffic

Fully HSDPAcoverage for

major area!

Major areadense urban urban

Dense urban

Urban

Suburb


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HSDPA outdoor coverage

Node B

Adaptive modulation

Good channel state: 16QAM

Adaptive coding rate

Good channel state: 3/4

AMC

HSDPA requires a good channel condition for high speed service:

Good channel stateNear to Node B

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

hotspot

Micro Node B is more suitable for HSDPA


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HSDPA indoor coverage

HSDPA indoor coverage

CBD (focus on)

Office, hotel, etc

Shopping center, airport, etc

Macro Node BIndoor distributed system

Macro Node B/base band poolRRU

Indoor distributed system

Micro Node BIndoor distributed system

Pico

Solution

Transmission

Pico

RRU

Power

distributor

Twisted

pair

Fiber

Feeder

Macro Node B orbase 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 enoughIs the

transmission enough?

the indices of indoor distributedcomponents (like power distributor)

required by HSDPA and R99 are same,

So the existing indoor distributed system

of R99/R4 is suitable for HSDPA


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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 ~120RNC Add 5

Node B Add 10

Planning Area: 30km2

Subscribers: 80000

HSDPA network planning case study


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For capacity

R99 cell peak data rate:

7384Kbps=2.688Mbps

HSDPA cell peak data rate:

15960Kbps3/4 = 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

ZTE serialized Node B support HSDPA


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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 designHSDPA

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


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04 Umts Hsdpa Technology-55

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Transcript of 04 Umts Hsdpa Technology-55