CDMA PLANIF

8/4/2019 CDMA PLANIF

http://slidepdf.com/reader/full/cdma-planif 1/32

Sommaire

Chapitre 1: Introduction of CDMA Technologies

Chapitre 2: Process of Radio Network Planning

and Optimization

Chapitre 3: PN offset Planning



Multi-Access Technology

Time

Frequency

CodeCDMA

User 3

User 2

User 1



1st Generation1980s (analog) 2

nd

Generation1990s (digital) 3rd

Generationcurrent (digital)

3G provides: Complete integrated service solutions High bandwidth Unified air interface Best spectral efficiency

AMPS

Analog to DigitalTACS

NMT

OTHERS

GSM

CDMA

IS95

TDMAIS-136

PDC

UMTSWCDMA

CDMA2000

TD-SCDMA

Development of Mobile Communications Introduction

Voice to Broadband



3G Objectives

3G is developed to achieve:

Universal frequency band for standard and seamless global

coverage

High spectral efficiency

High quality of service with complete security and reliability

Introduction



3G Objectives

•Easy and smoothly transition from 2G to 3G, compatible with 2G

•Provide multimedia services, with the rates:

• Vehicle environment: 144kbps• Walking environment: 384kbps• Indoor environment: 2Mbps



Sommaire


Chapitre 2: Radio Network Planning and

Otpimization




Coverage Quality CostCapacity

Achieve a mobile network with

•better coverage

•large capacity and

•future proof

Efficient Networking

Objective of RNP



Capacity Analysis

Estimate number of subscribers

long-term predictions

demanded number

Expected traffic load per subscriber

data calls domination

voice calls domination

Particular phone usage by the subscribers

thin & thick areas

phoning during some special events

Process of RNP



Process of Radio Networw Planning andOptimization

•Network Planning and optimization are two key elements very important

For the whole of mobile network construction

•Network Planning is start when the contract is signedand ends when the report is submitted



Process of Radio Networw Planning andOptimization

Dimensioning Planning & Implementation O & M

Requirements

- Capacity

- Coverage

- QoS

Dimensioning

-Link Budget

-Capacity

analysis

Equipment

Number

Coverage Planning

& Site Acquisition

- Simulation

- Search ring

- Site Survey

Capacity Planning

- Traffic

- Service

PN offset Planning

Parameter Planning

- Area/Cell Specific

- Handover Type- Maximum load

Network Construction

Installation Test

- Cell Test

- Cluster Test

- System Test

Network

Optimization

- Statistics

- Measurement

- User Claims

Network Re-

engineering

- Increase FA- Add Equipment

- Relocating



Sommaire


Chapitre 2: Process of Radio Network Planning and

Optimization




Séquence de Cryptage de (M)

Two types of codes are used in a CDMA2000 system,

i.e. orthogonal code and pseudo-noise code.

Pseudo-noise codes used in a CDMA2000 system are

of two types

m-sequence with length 215-1

and that with length 242-1.

Techniques & Technologies de CDMA



Short Code

In a CDMA system, a pair of m-sequences with length 215 chips

are used as the spectrum spreading codes for forward and

backward links.

This pair of m-sequences are also the pilot codes for pilot

channels, and different sectors are assigned different pilot code

phases.

with the phase difference between adjacent phases required to be

at least 64 bits. So the maximum number of available phases is:

215 /64=512.



Long Code

The long code is a sequence of PN with one period of 242-1 çhips

Functions of long code:

Encoding the channel of shameless CDMA

Control the insertion of the bit of control of energy

To spread out information over the channel of CDMA reversed to

identify the stations of MS



Walsh Code

W2n=Wn Wn

Wn Wn

W1=0

W2=0 0

0 1

W4 =

0 00 1

0 00 1

0 00 1

Walsh code

64-order Walsh function is used as a spreading function and

each Walsh code is orthogonal to other.

Walsh Code is one kind of orthogonal code.

A Walsh can be presented by Wim where ith (row) is the

position and m is the order. For example, W24 means 0101

code in W4 matrix

1 1

1 0



Walsh Code

•In a CDMA system, the 1.2288Mbit/s 64-order Walshfunction is used to spread the spectrum of each code

multiplexed forward channel so as to make code

multiplexed forward channels orthogonal to each other.

•A code multiplexed forward channel spread by using 64-order Walsh function n (n=0-63) is defined as code

multiplexed channel n, wherein “Walsh function n” refers to

row n+1 in the above Walsh function matrix.

The sequence number function of the pilot channel is “0”,

namely, Wal (64, 0).



Variable Walsh codes

64

4

8

16

32

12

9600 19200 38400 76800 153600 307200 614400

Data Rate(bps)-

W01=0

W02=00

W12=01

W04=0000

W24=0011

W14=0101

W34=0110

W08=00000000

W48=00001111

W28=00110011

W68=00111100

W18=01010101

W5

8=01011010

W38=01100110

W78=01101001

( W016,W

816)

( W416,W

1216)

( W216,W

1416)

( W616,W

1416)

( W116,W

916)

( W516,W13

16)

( W316,W

1116)

( W716,W

1516)

The Walsh Code for The data rate



Search Windows

•SRCH_WIN_A : used to search the activated and candidate pilot set

•SRCH_WIN_N : used to search the adjacent pilot set

•SRCH_WIN_R : used to search the remaining pilot set

•The measurement unit for each window is “chip”.



Size of windows

In a CDMA system, two adjacent PN offsets must beseparated from each other at an interval of at least 64 chips.

•1 chip=3×108/1.2288M=244.14(m)•64 chips=64×244.14=15.6(km)



PN Planning

PNa

PNc

PNb



Purpose of PN Offset Planning

•In CDMA we have two m-sequence with lenght 215

•We have a limited number of PN Offset planning, a maximum is512

•And we must be developed to avoiy any confusion

•if we would have a same PN offset , thus causing interference



Pilot_inc

•The value of PILOT_INC determines the phase differencebetween pilots of different cells

•In reality, due to complicated radio propagation environmentsand limited sizes of MS search windows, the 15.6km separation

is not enough for distinguishing between two adjacent PN offsetsin an actual PN offset planning.

•For this reason, we use parameter PILOT_INC to set the numberof available PN offsets.

•Available number of PN offsets=512/PILOT_INC



Lower Limit Of Pilot_inc

The numbers are generally according to the

environment : 1;2; 3;4



Lower Limit of Pilot_inc

Rayon de régiond'assurance

r (m)

r(morce

aux)

SRCH_ WIN_ A

Taille deSRCH_WIN

_A(morceaux)

S 1 A PILOT_INC LimiteinférieuredePILOT_INC

Nombred'excentragesdisponibles de

PN

500 2.048 0 4 2 0.17893832 1 512

500 2.048 1 6 3 0.19456332 1 512

500 2.048 2 8 4 0.21018832 1 512

500 2.048 3 10 5 0.22581332 1 512

500 2.048 4 14 7 0.25706332 1 512

500 2.048 5 20 10 0.30393832 1 512

500 2.048 6 28 14 0.36643832 1 512

500 2.048 7 40 20 0.46018832 1 512

500 2.048 8 60 30 0.61643832 1 512

500 2.048 9 80 40 0.77268832 1 512

500 2.048 10 100 50 0.92893832 1 512

500 2.048 11 130 65 1.16331332 2 256

500 2.048 12 160 80 1.39768832 2 256

500 2.048 13 226 113 1.91331332 2 256

500 2.048 14 320 160 2.64768832 3 170

500 2.048 15 452 226 3.67893832 4 128



Engineering Approaches to PN OffsetPlanning

•According to the previous analyses:

•the PILOT_INC lower limit, is “4” in practical applications

•the number of available PN offsets is 128 and the adjacent offset separation is256 chips

•A pilot signal must travel at least 62Km in order to fall into search windowSRCH_WIN_A for another pilot.



Approach 1 to PN offset planning

Cell No. Sector 1(Group A) Sector 2 (Group B) Sector 3 (Group C)

Cell 1 4 172 340

Cell 2 8 176 344

Cell 3 12 180 348

... ... ... ...

Cell n n*4 (n+42)*4 (n+84)*4

... ... ... ...

Cell 37 148 316 484

i2 ij j2

If N is the number of cells in a reuse cluster, it should be

N=37 for this example



Approach 2 to PN Offset Planning

Sub-cluster 1

Sector 1 4 20 36 52 68 84 100 116 132 148 164

Sector 2 172 188 204 220 236 252 268 284 300 316 332

Sector 3 340 356 372 388 404 420 436 452 468 484 500

Sub-cluster 2

Sector 1 8 24 40 56 72 88 104 120 136 152 168

Sector 2 176 192 208 224 240 256 272 288 304 320 336

Sector 3 344 360 376 392 408 424 440 456 472 488 504

Sub-cluster 3

Sector 1 12 28 44 60 76 92 108 124 140 156

Sector 2 180 196 212 228 244 260 276 292 308 324

Sector 3 348 364 380 396 412 428 444 460 476 492

Sub-cluster 4

Sector 1 16 32 48 64 80 96 112 128 144 160

Sector 2 184 200 216 232 248 264 280 296 312 328

Sector 3 352 368 384 400 416 432 448 464 480 496



Distribution of cells in a sub-cluster

As shown above, cells in a sub-cluster are distributed in a spiral

We have used the sector 1



Reuse cluster layouts

148 164 152 168 148 164 152 168

132 20 36 136 24 40 132 20 36 136 24 40

116 4 52 120 8 56 116 4 52 120 8 56

100 84 68 104 88 72 100 84 68 104 88 72

156 160 156 160

140 28 44 144 32 48 140 28 44 144 32 48

124 12 60 128 16 64 124 12 60 128 16 64

108 92 76 112 96 80 108 92 76 112 96 80

152 168 148 164 152 168 148 164

136 24 40 132 20 36 136 24 40 132 20 36

120 8 56 116 4 52 120 8 56 116 4 52

104 88 72 100 84 68 104 88 72 100 84 68160 156 160 156

144 32 48 140 28 44 144 32 48 140 28 44

128 16 64 124 12 60 128 16 64 124 12 60

112 96 80 108 92 76 112 96 80 108 92 76




application case of PN offset planning




ETUDE DE CAS



Documents

CDMA PLANIF