6-CRNP Capacity Planning

7/28/2019 6-CRNP Capacity Planning

http://slidepdf.com/reader/full/6-crnp-capacity-planning 1/52

Huawei Confidential. All Rights Reserved

0RG004601 CDMA1X Capacity planning

Issue 3.0



Internal Use

Chapter 1 Characteristics of CDMA Network

Chapter 2 Interference analysis

Chapter 3 Reverse link capacity analysis

Chapter 4 Forward link capacity analysis

Chapter 5 Capacity planning



Internal Use

Capacity Analysis

In CDMA system, all cells shares the same spectrum, which increases

the capacity of a CDMA system. However the use of same frequencies

may cause for multi-address interference. This kind of interference

can restrict the system capacity. The capacity of a radio system is determined by both the forward and

reverse links. During the capacity planning. The analysis should be

based upon both the forward and reverse links.

Because of distributed sources, in general we concentrate more on

the reverse link capacity.

Character istics of CDMA network



Internal Use

Basic Capacity Model

Limited interference model

ITOT=Iown+Iother +PN+T

Iown Interference from subscribers in the local cell

Iother Interference from subscribers in the neighboring cells

PN Background noise of receiver

T External interference

Limited power model

PTOT=Ppil+Psync+Ppag+Ptraf +Pother

Ppil Power of pilot channelPsync Power of synchronous channel

Ppag Power of paging channel

Ptraf Power of traffic channel

Pother Power of other channel

Character istics of CDMA network



Internal Use








Internal Use

Interference at reverse link

I own Interference from subscribers in the local cell

Interference each subscriber should overcome: ITOT - P j

P j is the receiving power of jth subscriber , V j is the voice activationfactor

Provided that the power control is ideal, then:

The value of Pj can be obtained:

The subscriber interference in the local cell is equal to the sum of allother subscribers power reaching the receiver:

I nterf erence analysis


http://slidepdf.com/reader/full/6-crnp-capacity-planning 7/52Internal Use

Interference due to the neighboring cell subscribers

It is difficult to conduct theoretical analysis of the interference

contributed by the neighboring cell subscribers, which is closely

related to the subscriber distribution, actual cellular layout, load

of neighboring cell, antenna pattern, etc.

f is adjacent cell interference factor and it is the ratio between the

intercell interference to the intra cell interference, i.e.

If the subscribers are distributed uniformly,

The typical value of f is 0.55 for an omni-directional cell

The typical value of f is 0.65 for 3-sectors directional cell

Interference at reverse linkI nterf erence analysis



Let

We can write

Since




Where is uplink load factor:

The two main components of the reverse interference depends upon the cell load

When the load factor is equal to 1, ITOT reaches infinite. In this case, the corresponding

capacity is called the limit capacity

Assuming：

Power control is ideal

Interference from subscribers from neighbor cells is constant

From last equation we get




Relationship between load factor and reverse interference

50% load -- 3dB

60 % load -- 4dB

75 % load -- 6dB




Iown from subscribers in the local cell (Less interference due to Rake receiver)

Forward coherent demodulation of the local cell, the interference originates from

multipath, and defining the multipath factor. In the following graph, the horizontal

axis indicates the number of multipath components and the vertical axis

indicates the ratio of the co-channel interference to the total power spectrum in

the same cell. The distribution of multipath energy has a certain rule, according

to it, 87% of the energy is distributed into three strongest multipaths. The Rakereceiving technology is adopted to compensate this effect and achieve the 2-3dB

demodulation gain.

Interference at forward linkI nterf erence analysis



Internal Use

Interference at forward linkI nterf erence analysis

Interference from the neighboring cell subscribers

The interference from the neighboring cell is closely related to the

subscriber distribution. At the center of BTS, the interference from

the neighboring cell is very small, while at the edges of the cell, the

interference is very large

The horizontal axis indicates the distance from the mobile station

to the BTS, and the vertical axis indicates ratio of the forward link

interference from other cells to the forward link power received by

the local BTS (Ioc /S).



Internal Use

How to Control Interference

Influence of interference upon the network

Successful handoff rate

Access efficiency

Call drop rate

Conversation quality

How to control interference

Improve power control

Improve the Rake receiving efficiency

Reasonable network planning

I nterf erence analysis



Internal Use








Internal Use

Reverse Capacity Model – Soft Blocking Model

)

)1(

)1((

22

22

222

2

1

0

e M

e M X R

W

Q Bcdma

dt e xQt

x

2/2

2

1)(

0 X : Indicating the permitted cell load, determined by factors such as cell

coverage, etc.

10/)10(ln,)/( t b N E e

2 、 : First order and second order factors for speech activation

、: First and second order interference factor

: Power control covariance

M : Cell capacity (Erlang)

RW / : Spread frequency gain

CDMA B : Soft blocking possibility

Reverse l ink capacity anal ysis



Internal Use

Soft Capacity of the CDMA 1X System

Reverse Capacity Test Results: Mean system load 70%

Soft blocking rate 2%

Interference factor 0.1

Power control covariance (dB) 2.5

Activation factor 1

Mean Eb/Nt value of traffic channel (dB) 2.7

Sector factor 2.55

Throughput of traffic channel in omni-directional

cell (Kbps)

307

Throughput of traffic channel in 120º sector

(Kbps)

261

Throughput of S111 BTS in 3-sector cell (Kbps) 783




Internal Use

Static 3km/h 8km/h 30km/h 100km/h

Mean load of thesystem

50% 50% 50% 50% 50%

Service blocking rate 2% 2% 2% 2% 2%

Interference factor 0.55 0.55 0.55 0.55 0.55

Basicparameter

Second order interference factor

0.086 0.086 0.086 0.086 0.086

Power controlcovariance (dB)

2.5 2.5 2.5 2.5 2.5

Sector factor 2.55 2.55 2.55 2.55 2.55

Activation factor Select 0.4 for voice service and 1 for data service

Servicedemodulation

threshold

6.6 7 7.8 9.2 8.8

IS95 voice Throughput of omni-directional BTS

(Kbps)

78.5 70.6 56.9 38.7 43.3

Throughput of directional TRX

(Kbps)

66.8 60.0 48.4 32.9 36.8

Typical values of reverse capacity


Eb/Nt increase

Throughput decrease



Internal Use

1X9.6K voice Service demodulation

threshold

5.08 5.57 6.34 7.13 6.78

Throughput of omni-

directional BTS

(Kbps)

117.2 103.1 84.2 68.2 74.9

Throughput of directional

TRX (Kbps)

99.6 87.6 71.5 57.9 63.6

1X19.2K

data

Service demodulation

threshold

3.4 4.11 4.96 5.96 5.37

Throughput of omni-

directional BTS(Kbps)

138.5 113.0 88.1 65.4 78.0


TRX (Kbps)

117.7 96.0 74.9 55.6 66.3

1X38.4K

data


threshold

2.59 3.01 3.64 4.78 4.26

Throughput of omni-

directional BTS

(Kbps)

145.7 128.4 105.9 74.2 87.4


TRX (Kbps)

123.8 109.1 90.1 63.1 74.3

Typical values of reverse capacityReverse l ink capacity anal ysis



Internal Use

1X76.8K data Service demodulation

threshold

2.15 2.47 3.01 4.28 3.57

Throughput of omni-

directional BTS (Kbps)

131.5 118.7 99.5 65.1 82.7


TRX (Kbps)

111.8 100.9 84.6 55.4 70.3

1X153.6Kdat

a


threshold

1.54 1.98 2.51 3.8 2.68

Throughput of omni-

directional BTS (Kbps)

118.8 102.1 84.8 53.4 79.9


TRX (Kbps)

101.0 86.8 72.1 45.4 67.9

Typical values of reverse capacityReverse l ink capacity anal ysis



Internal Use

Mean Reverse Throughput of Sector TRX

Md= KiRi

M = Md.PdVi+Mv.PvVi

Mv :Throughput of TRX voice service

Md:Throughput of TRX data service

Ki: Proportion of different service access

ratesRi: Different service access rates

Pd: Data subscriber proportion

Pv: Voice subscriber proportion

VI: Proportion of subscriber movement rate

At different service access rates, the air interface of the cdma-1X

system has different capacity. With the combination of traffic model

and subscriber proportion, the basic capacity of air interface can be

planned. Use the following formula:

Capacity planni ng



Internal Use

According to the traffic model provided by Zhengzhou Research Institute andthe subscriber proportion, the calculated TRX capacity of embedded omni-

directional cell is 110kbps in reverse link and 300kbps in forward link. For 120º

sector site, it is 94kbps in reverse link and 255kbps in forward link.

Reverse Capacity at Different Rates and SpeedsCapacity planni ng

Application rate proportion Static 3km/h 8km/h 30km/h 100km/h

Data subscriber 90% 5% 3% 2% 0%

Voice subscriber 60% 20% 14% 5% 1%

Access rate proportion 9.6kbps 19.2kbps 38.4kbps 76.8kbps 153.6kbps

Data subscriber 85% 8% 6% 1% 0%

Proportion of

subscriber service

type

Voice

subscribers

Data

subscribers

Mixed service

subscribers

Proportion of

voice

subscribers

Proportion of

data

subscribers

90% 0% 10% 90% 10%



Internal Use








Internal Use

Note: The numbers in red indicate “exceeding the throughput of

single TRX”, which is solved by adding more TRXs.

TRXs & CE Configuration in the System (S1/1/1)

Capacity planni ng

Number of

subscribers per

sector

Voice service flux

(kbps)

Channels needed

for voice

service

Data service flux

(kbps)

Channels needed

for data

service

100 7.68 2 0.15 0.01

250 19.2 5 0.38 0.03

550 42.24 11 0.84 0.06

1150 88.32 23 1.75 0.12

1750 134.4 35 2.67 0.19

The real project planning should be based on the detailed subscriber configuration according to

the coverage planning and the subscriber distribution. The subscriber distribution is relatively

sparse in suburb areas, a small number of channels can meet the requirements, while in denseurban areas, the subscribers are distributed densely, so more channels are needed to meet the

capacity requirements. The typical configuration is given below:



Internal Use

Capacity planni ng

The following results can be obtained from the above analysis:

Number of

subscribers per BTS

Basic configuration Considering soft

handover

Considering access

channel

Actual configured

channels considering

the blocking rate

100*3 S2/2/2 S3/3/3 S4/4/4 S7/7/7

250*3 S6/6/6 S8/8/8 S9/9/9 S12/12/12

550*3 S12/12/12 S16/16/16 S17/17/17 S21/21/21

1150*3 S24/24/24 S31/31/31 S32/32/32 S36/36/36

1750*3 S36/36/36 S47/47/47 S48/48/48 S52/52/52

Note: The numbers in red indicate “exceeding the throughput of

single TRX”, which is solved by adding more TRXs.

TRXs & CE Configuration in the System



Internal Use

Forward Link Capacity Model

].)(

.10[..

)(m ax

m ax

10/)(

m ax

pag

pag

p

sync

sync

pil

f T m

dB M

traf traf

traf

PG N

PG P K R L N P

K PG P M

)( ma x P M : Forward capacity )(dB M : Demodulation threshold allowance

ma x P : Maximum permitted power of BTS : Speech activation factor (being 0.4 generally)

traf PG : Processing gain of traffic channel; sync PG : Processing gain of synchronous channel;

pag PG : Processing gain of Paging channel traf : Demodulation threshold of traffic channel;

pil : Demodulation threshold of pilot channel; sync : Demodulation threshold of synchronous channel;

pag : Demodulation threshold of paging channel p N : Number of paging channels in the cell

m N

: Thermal noise traf K

: Subscriber distribution factor f K : Forward integrated interference factor (including interference inside and outside the cell)

)( R LT : Forward link attenuation (corresponding to the cell radius actually)

Forward li nk capacity analysis



Internal Use

Forward Capacity Test ResultsForward li nk capacity analysis

Background noise (dBm) -105

Path loss (dB) 130

System interference index 1.4

Geographic distribution coefficient of subscribers 0.4

Maximum transmitting power (W) 20

Demodulation threshold of pilot channel (dB) -15

Demodulation threshold of synchronous channel (dB) 6

Demodulation threshold of paging channel (dB) 6

Demodulation threshold of traffic channel (dB) 7

Throughput of omni-directional station (Kbps) 401

Throughput of traffic channel in 120º sector (Kbps) 341

Throughput of S111 BTS in 3-sector cell (Kbps) 1024

Forward Capacity Test Results:

Generally: Forward Capacity > Reverse Capacity

T i l V l Of F d C it



Internal Use

Typical Value Of Forward Capacity

static 3km/h 8km/h 30km/h 100km/h

Basic Parameter thermal noise -105 -105 -105 -105 -105

forward link attenuation 130 130 130 130 130

forward link interference factor 2 2 2 2 2

subscriber distribution factor 0.4 0.4 0.4 0.4 0.4

BTS maximum transmission power (W) 20 20 20 20 20

pilot channel demodulation threshold (dB) -15 -15 -15 -15 -15

sync channel demodulation threshold (dB) 6 6 6 6 6

paging channel demodulation threshold (dB) 6 6 6 6 6

CDMA 1X 9.6k Voice service service demodulation threshold 6.8 7.46 8.49 9.54 9.08

cell throughput (Kbps) 285.7 245 193 152 169

CDMA 1X 19.2k Data service service demodulation threshold 4.8 5.8 7 8.41 7.58


CDMA 1X 38.4k Data service service demodulation threshold 4.5 5.23 6.32 8.31 7.4





cell throughput (Kbps) 654.46 530 411 221.76 379.21




Internal Use

Forward Capacity Characteristics of the System

For different service type, the total capacity of equipment is

different.

The movement speed has great influences on the system

capacity.

In the central area of a cell, the forward interference is

mainly because of multipath.

At the borders of a cell, the forward interference is mainly

because of the neighboring cells.

The capacity of forward link depends upon the total

transmitting power of the cell and the distribution of the

transmitting power in the traffic channel and other additional channels.

The subscriber distribution has direct influence upon the

forward capacity of the BTS.


C i f C it Ch t i ti



Internal Use

Reverse capacity

The coherent demodulation of reverse pilot is adopted for traffic

channels and the Turbo code is used for the data service so that

the reverse demodulation performance is improved. The reverse

capacity of the CDMA-1X is 2 to 3 times that of the IS-95.

Forward capacity

The quick power control technique is used for the forwardchannel so that the power control accuracy is improved and the

mean forward transmitting power is decreased. Moreover turbo

code is used for the data service. The forward capacity of the

CDMA-1X is 1.5 to 2 times that of the IS-95.

Comparison of Capacity Characteristics

between IS-95 and CDMA-1X Forward li nk capacity analysis



Internal Use








Internal Use

Considerations in CDMA 1X Network Planning

Area division and traffic model analysis

Determine the planned capacity of single TRx in the target area

Conduct capacity-based network planning so as to determine the

number of BTSs and TRxs.

Configuration of BTS

Configuration of Abis interface

Configuration of BSC

Configuration of A interface

Configuration of MSC

Configuration of PDSN and Radius Server

Capacity planni ng



Internal Use

CDMA 1X Capacity Planning

Data-Voice Traffic Model

Configuration of TRXs and Channel

Resources in the System

Capacity planni ng

V i S i M d l



Internal Use

Voice Service Model

For voice service, the 2G and 3G systems do not differ withrespect to subscriber behavior, service type and resource

occupation. A standard model is available for the 2G voice service

in the telecom industry, so the analysis results of the model are

directly quoted.

Voice service model

Service blocking rate 2%

Primary channel rate (Kbps) 9.6

Traffic (Erl) 0.02

Soft handover proportion 30%

Capacity planni ng

V i C i D ib d i Th h



Internal Use

For voice services, the fixed rate channel is adopted and Erl isused to describe the processing capability of equipment. Once the

data service is imported, different services lead to different mean

subscriber rates, in such case it is difficult to describe the

occupation in Erl. To describe this, Huawei uses throughput, which

is:

Throughput = Traffic strength*Data rate*Activation factor

Voice Capacity Described in Throughput

r AvS

Capacity planni ng

D t S i M d l (1)



Internal Use

Data Service Model (1)Capacity planni ng

Sum (Data service rate x Statistic proportion of distribution)

Estimated action of high end users in the



Internal Use

Throughput at busy hour: 3600321 R M M M T nS

M1: Centralized coefficient on busy day N: Access service count T: Mean communication time

M2:Centralized coefficient on busy hours M3: duty cycle R: Mean data service rate

Capacity planni ng

Information

query

WWW

browse

& WAP

E_mail FTP Voice & video

multimedia flow

service

E-

commerc

e

Other

s

Monthly use times 60 60 60 60 5 20 15

Centralized

coefficient on

busy day

0.05 0.05 0.05 0.05 0.05 0.05 0.05

Centralized

coefficient on

busy hours

0.1 0.1 0.1 0.1 0.1 0.1 0.1

Mean use time (s) 120 300 15 30 300 120 60

Duty cycle 0.1 0.1 0.75 0.8 0.8 0.1 0.1

Throughput (bps) 26.21 65.53 24.57 52.42 43.68 8.74 3.28

Estimated action of high-end users in the

early phase of network

Estimated action of high end users in the



Internal Use

Capacity planni ng

Information

query

WWW

browse

& WAP

E_mail FTP Voice & video

multimedia flow

service

E-

commerc

e

Other

s

Monthly use times 60 60 60 60 5 20 15

Centralized

coefficient on

busy day

0.05 0.05 0.05 0.05 0.05 0.05 0.05

Centralized

coefficient onbusy hours

0.1 0.1 0.1 0.1 0.1 0.1 0.1

Mean use time (s) 120 300 15 30 300 120 60

Duty cycle 0.1 0.1 0.75 0.8 0.8 0.1 0.1

Throughput (bps) 26.21 65.53 24.57 52.42 43.68 8.74 3.28

Estimated action of high-end users in the

early phase of network

The throughput of high-end subscribers is 250 bps

The uplink and downlink proportion is 1:4

Thus uplink throughput is 50bps and downlink throughput is 200bps

Total throughput = 250bpsTotal throughput = 250bps

D t S i M d l (2)



Internal Use

The throughput of the low-end subscribers is 35 bps The uplink and downlink proportion is 1: 4

Thus the uplink throughput is 7bps and the downlink throughput is 28bps.

Capacity planni ng

Information

query

WWW

browse &

WAP

E_mail FTP Voice &

video

multimedia

E-commerce Others

Monthly useage 30 30 20 30 0 10 10

Centralized

coefficient on busy

day

0.05 0.05 0.05 0.05 0 0.05 0.05

Centralized

coefficient on busy

hours

0.1 0.12 0.1 0.1 0 0.1 0.1

Mean use time (s) 120 300 15 30 0 120 60

Duty cycle 0.1 0.1 0.75 0.8 0 0.1 0.1

Throughput (bps) 4.80 14.40 3.00 9.6 0 1.60 0.8

Total throughput = 250bpsTotal throughput = 35bps

Data Service Model (2)

Cl ifi ti d D fi iti f S b ib B h i



Internal Use

Classification and Definition of Subscriber Behavior

Capacity planni ng

r v AvS 9600

Service allocation and value of voice subscribers (reverse channel)

Subscriber type Proportion Traffic of single

subscriber (Erlang)

Data service throughput of single subscriber (bps)

Voice 100% 0.02 =76.8

Pure voice subscriber service model

S S d

S S d

Service allocation and value of voice subscribers (reverse channel)

Subscriber type Proportion Data service throughput of single subscriber (bps)

Low-end pure data

subscriber

80%

= 7

High-end pure data

subscriber

20%

= 50

Pure data subscriber service model




Internal Use

Capacity planni ng

l l t t

r d v

P S P S

AvS

9600,

Allocation and value of mixed service (reverse channel)

Subscriber type

Proportion

Traffic of single

subscriber (Erlang)

Data service throughput

of single subscriber (bps)

Mixed service throughput of

single subscriber (bps)

voice 100% 0.02 76.8

=92.4High-end data 20% - 50

Low-end data 80% - 7

Mixed service model





Internal Use

Data Voice Traffic Model

Configuration of TRXs and ChannelResources in the System


Configuration Procedures of BSS Equipment



Internal Use

Configuration Procedures of BSS Equipment

Calculate the subscriber throughput according

to the traffic model and subscriber distribution

Calculate the number of channels

to configure the BTS

Configure the BSC voice processing board and data processing board

according to the channel type and the number of each type of channel

Configure the number of links such as A1/A2，A10/11 and

A3/A7 according to the traffic model

The coverage and capacity planning are

combined with the calculation of the number of

TRXs and BTSs

Capacity planni ng

Flow Diagram



Internal Use

Um interface channel (FCH with soft handoff +

SCH without soft handoff + Common channel）

Characteristics of the CSM5000 chip:

In forward direction 64 CEs, each CE can

demodulate a 9.6k FCH/SCH

In reverse direction 32 CEs, each CE can

demodulate a 19.2k SCH/FCH

Characteristics of DSP chip:

The voice FCH channel is equivalent to a 9.6k channel

The data FCH channel is equivalent to a 9.6k channel

The data SCH channel is equivalent to multiple 9.6K

channels

Abis interface (including

soft handoff branch)

Voice Data

Channel Processing Board

FMR frame processing board

PM Frame TC Frame

(Not including soft handoff

branch)

Voice channel Data channel

Capacity planni ng

Flow Diagram

Characteristics of Equipment



Internal Use

Characteristics of Equipment

In the CDMA-1X system, different channel boards have different processing capability.

Therefore, analysis the processing capability of each channel processing unit beforeconfiguration.

Channel processing board of BTS: At present, two types of boards are available

1: With four CSM5000 chips.

Each CSM5000 chip process the 64 forward CEs and 32 reverse CEs.

2: With two CSM5000 chips.

FMR board (BM/BSC): Each board provides 320 channels demodulation resources.

Each demodulation resource can process an FCH channel or a 9.6k SCH channel.

EVC board (TC/BSC): Each board provides 192 voice channels processing units.

PPU board (PM/BSC): Each PPU board provides data throughput of 16Mb and each

PM frame can provide 2500 activated PPP connections.

Capacity planni ng

A case study



Internal Use

Suppose the subscribers in Area 1 are 800000

The subscriber service behavior: Number of pure voice subscribers Pv=90%，

Number of pure data service subscribers Pd=0%，

Number of mixed service subscribers Pv,d=10%.

Plan according to the 50% mean load

The blocking rate of the system is 2%

The voice traffic is 0.02Erl.

The mean throughput of high-end subscribers is 250bps.The mean throughput of low-end subscribers is 35bps.

The proportion of forward and reverse subscriber data is 4:1.

A case studyCapacity planni ng

TRX & CE Configuration



Internal Use


Capacity planni ng

TT

TRxNum

ber of

subscribers, a

single TRx can

Accommodate

M

Minimumn

umber of TRXs

needed

B

BTS

type

N

Number of

subscribers, asingle TRX can

Accommodate

M

Minimum number

of BTSs needed

S1 1229 651 S1/1/1 3687 217

O1 1437 557 O1 1437 557

Mean subscriber throughput in the coverage area = Sv × Pv + Sd× Pd + Sd,v× Pd,v

= 76.8*90%+92.4*10%=78.36bps

Number of subscribers a single TRX can accommodate = Mean throughput of a single TRX

Mean subscriber throughput in the coverage area

=94*1024/78.36=1229

Number of TRXs needed = Number of subscribers in the coverage area

Number of subscribers a single TRX can accommodate

= 800000/1229=651

For 120º sector site, the calculated TRX

capacity is 94kbps in reverse link




Internal Use

BTS channel board, the forward and reverse CEs process the forward and

reverse channels independently. Each forward CE can demodulate an FCH or a9.6k SCH channel, while a reverse CE can demodulate an FCH channel or a

19.2k SCH channel. In one BTS, multiple sectors share the same CE resources.

Please configure the CEs based upon the subscriber services in the coverage

area of each BTS.

In actual application, common channels should be reserved for the cells. For

each sector, a reverse CE should be reserved for reverse access channel.

While three forward CEs should be reserved for the processing of forward pilot,

synchronous and paging channels.

Soft handoff branches of the CDMA system occupy the CE processing

resources. Currently only FCH takes part in the soft handoff while the SCH

does not take part in the soft handoff. During the data service analysis,

carefully consider which data are transferred by the FCH channel and which

data are transferred by the SCH channel.

In a BTS, currently two types of channel boards are provided, type A and B.

Capacity planni ng





Internal Use

In our example, the voice subscribers are 90%, so we consider the reverse limitation i.e. configure the channels in reverse way.From observations, when the data subscribers reach 70% then there will be the forward limitation on resources. The reverse

configuration method is as follows: Voice channel resource = Voice subscriber throughput

Voice flux/Voice activation factor FCH channel resource = FCH data throughput

(Primary rate of FCH data*Utilization ratio of data demodulation resource) SCH channel resource= SCH data throughput

(Primary rate of SCH data* Utilization ratio of data demodulation resource)

The SCH channel does not take part in the soft handoff. Total channel resource after soft handoff =

(Voice channel resource + FCH channel resource)

(1 - Soft handoff proportion) Consider configuring a common access channel for each sector. Number of channels to be configured = ErlB_B (Basic channel resource of BTS, service blocking rate) Voice subscriber throughput = Planned number of subscribers a single TRX can accommodate*

（Proportion of pure voice subscribers + Proportion of mixed service subscribers） * Voice subscriber throughput

Capacity planni ng


+SCH Channel Resource




Internal Use

The detailed configuration of channels and CSM5000 chips should be based upon the

coverage of the BTS and the number of subscribers a single TRX can accommodate. For

the initial planning, we can configure according the approximate estimation of the traffic

coverage:

The number of subscribers a single TRX can accommodate according to the

analysis results of the model developed by Zhengzhou research institute: 1229

Voice throughput =1229*(90%+10%)*76.8=94387.2bps

Data FCH throughput =(1229*10%*80%*7)+(1229*10%*20%*50*36.6%)=1138.05bps

Data SCH throughput =1229*10%*20%*50*63.4%=779.19bps

Number of voice channel resources =94387.2/(9600*0.4)=24.58

Number of data FCH resources =1138.05/9600=0.12

Number of data SCH resources =779.19/(9600*1.5)=0.05

Considering 30% soft handoff =[(24.58+0.12)/(1-30%)]+0.05=35.3

Number of common channel per sector =1

Number of CEs per BTS =ErlB_B(36.3*3,0.02)=122

Number of channels needed for 800, 000 subscribers =122*217=26474

Capacity planni ng


Needs 2 pcs Type A CCPM,

or 1 pc Type B CCPM

FCH Throughput Proportion=

9.6/26.21x 100%

Calculation of BSC Processing Channel



Internal Use

Number of voice FCH channels = Number of subscribers*Proportion of voice

subscribers*Voice subscriber traffic

=800000*(90%+10%)*0.02=16000

Number of data FCH channels =(Number of subscribers* Proportion of data

subscribers*Proportion of low-end subscribers*Throughput of low-end

subscribers*Forward proportion+ Number of subscribers* Proportion of data

subscribers* Proportion of high-end subscribers* Throughput of high-end

subscribers*Forward proportion*FCH data proportion)/FCH processing

capability

=[(800000*(0%+10%)*80%*35*80%]+[800000*(0%+10%)*20%*250

*80%*36.4%)]/9600=308

Number of data SCH channels =(Number of subscribers * Proportion of data

subscribers * Proportion of high-end subscribers * Throughput of high-end

subscribers * Forward proportion *SCH data proportion)/SCH processing

capability =[800000*(0%+10%)*20%*250*80%*(1-36.4%)]/9600=212

Calculation of BSC Processing ChannelCapacity planni ng

Calculation of BSC Processing Channels



Internal Use

Number of FMR channels to be configured= Number of FCH channels/(1- softhandoff proportion) + Number of data SCH channels

=[(16000+308)/(1- 30%)]+212=23510

Number of voice channels in the TC frame (EVC)

= 800000*0.02= 16000

Reverse data traffic flow in the PM frame (PPU)

=(800000*10%*15.6/1024/1024)=1.2M

The forward and reverse proportion is 4:1, so the data traffic in the PM frame is

=1.2*5= 6Mbps

Provided that the subscribers are averagely distributed, then the hardwareresources to be configured are as follows:

Number of FMR boards = 23510/320= 74 pieces

Number of EVC boards = 16000/192= 84 pieces

Number of PPU boards = 6/16= 1 piece

Calculation of BSC Processing ChannelsCapacity planni ng

Data= Mixed –

voice= 92.4 – 76.8 = 15.6



Documents

6-CRNP Capacity Planning