3g basic issue 1-3 ovsf code thai

3rd Generation of Mobile Communications Advanced Info Service PLC.

1 | P a g e Radio Access BKK Composed by: Wutthilert Rungchai February 2010 Edit by: Bunjong Yosapa

ISSUE 1-3

Code CDMA (Code) ( FDMA

TDMA ) Spread

Scrambling

Scrambling Code

Scrambling Code

Channelization Code

Spreading

Scrambling

De-Spreading

De-Scrambling

Voice

Data

Voice

Data

1 code spreading scrambling



Scrambling Spread ( spreading )

Modulate Bit Rate

Bit Rate Spread

Spreading & Modulation

2 Spreading Despreading

2 (Data) (Spreading) ()

Spreading Code ( Channelization code



channel ) Spreading Signal Spreading Signal Despread

Spreading Code

Spreading (Data) Exclusive OR Spreading

Code Output Spreading Code Chip Rate

Spreading Code

Code WCDMA Code

(Channel) OVSF code (Orthogonal Variable

Spreading Factor) Code

Spreading Factor (SF) )

3 Code tree



3 OVSF Code Code

Spread Factor (SF) SF= 1 SF=256 (UL)/512 (DL)

Code CSF, No. 0 C1,1 (SF=1, No.=1) 00 C2,1 (SF=2, No.=1)

Code generation

(RNC)

WCDMA

A

A,A

A,-A 4 code

Code Code A Code

Code A A, A Code A Code A, -A

Code (A) Code Invert A Code A 1010 (SF=4) code

SF SF=8 = A,A = 10101010 A,-A = 10100101

WCDMA Code Spread Chip Rate 3.84 Mega chip per

second (Mcps) Code SF Mod Spread

3.84 Mcps



SF SF SF= 8 User Throughput

SF SF=128 User Throughput

SF SF SF = 4

chip Radio

SF SF

SF

Radio

Spreading Factor Spreading Factor

User throughput

User

User throughput

User

Correlation

Despreading

Correlation

(Code) CDMA

0 -1 () 1 +1 () 1

Exclusive OR ( 1 1)

[-1 +1] =0, [+1+1]=2, [-1-

1]=-2 Code ()



-1

+1

0

-1

-1 1 -1 1 1 1-1 1 -1 1 1 1

+1

0

-1

-1 1 -1 1 1 1

+1

0

-1 1 -1 1 1 1

1 1 1 1 1 1= +1+1+1+1+1+1= 6/6=1

5 Correlation

Exclusive OR ( = 0 -1

= 1) (1+1+1+1+1+1)/ = 6/6 = 1 Correlation

-1

+1

0

-1

-1 1 -1 1 1 11 1 -1 1 -1 1

+1

0

-1

-1 1 -1 1 1 1

+1

0

1 1 -1 1 -1 1

-1 1 1 1 -1 1

=-1+1+1+1-1+1= 2/6 = 0.33 6 2 ()

5 6 Function exclusive OR

Correlation = 0.33 2 6 Correlation 1



-1

+1

0

-1

-1 1 -1 1 1 11 1 1 1 -1 1

+1

0

-1

-1 1 -1 1 1 1

+1

0

1 1 -1 1 -1 1

-1 1 -1 1 -1 1

=-1+1-1+1-1+1= 0/6 = 0 7 Correlation 0 (zero) correlation

7 Zero Correlation

( ) Orthogonal

Orthogonal

Spread

Code

1 Correlation Auto Correlation Zero Correlation

Cross Correlation



Despreading

Code SF4,4(0110)

Input

output

8 Spreading Spreading code SF4,4

(Input) 2 1 0 Spreading Code Spreading Factor = 4

Code 4 ( Code tree code 0110 0 1

) -111-1 () Output

-111-11-1-11 ( 01101001) ()

Received

Code SF4,4(0110)

output

-1 1 1-1 1-1-1 1

-1 1 1-1 -1 1 1-1

1 -1

9



() = [Received SF code]/Code length = [-1 1 1-1 -1 1 1-1]/4 =

[1+1+1+1]/4 = 4/4 = 1

= [1-1-1 1 -1 1 1-1]/4 = [-1-1-1-1]/4 = -4/4 = -1

Exclusive OR 0 () -1

1

Received

Code SF4,4(0110)

output

-1 1-1-1 1-1 1 1

-1 1 1-1 -1 1 1-1

0.5 -0.5

10 despreading

1

= [-1 1-1-1 -1 1 1-1]/4 = [1+1-1+1]/4 = 2/4 =0.5

= [1-1 1 1 -1 1 1-1]/4 = [-1-1+1-1]/4 = -2/4 = -0.5

Correlation 1 1 (0)



Code Despread

Received

Code SF4,3(0101)

output

-1 1 1-1 1-1-1 1

-1 1-1 1 -1 1-1 1

0 0

11 SF code despread

Despread code (

) SF4,3 (0101)

= [-1 1 1-1 -1 1-1 1]/4 = [1+1-1-1]/4 = 0/4 = 0

= [1-1-1 1 -1 1-1 1]/4 = [-1-1+1+1]/4 = 0/4 =0

1 0 Idle

Orthogonal SF4,4 SF,4,3 orthogonal



Channelization code

Code

Code Spread Channelization Code Code

01

0101

0110

01010101

01011010

01100110

01101001

0110100101101001

0110100110010110

SF2 SF4 SF8 SF16

12 code

Code Code Code

Code

Code Code 00110011 (SF=8) Code

0011001100110011 0011001111001100 (SF=16) Code (SF=32,

64,..) Code 0011 Code Code 00111100

Resource planning



code Uplink SF 4 256 Downlink (DL)

SF 4 512 R99 EUL (Enhance UL) SF 2

Scrambling Code

Scrambling Code Channelization Code

Scrambling Code Downlink Channelization

Channel Scrambling Scrambling Code

Channelization code (SFn,m)

Channelization code (SFn,m)

Scrambling codeData in

Data in

13 Channelization code scrambling code

Scrambling Code BSIC Code

512 Code Uplink (UE) Scrambling Code RNC

Code UE Code Code 1 RNC

UE RNC ( RNC) Code



Scrambling Code Scrambling

Scrambling Spreading

Code Scrambling Code

(SC) Channelization Code

HSPA Carrier



Code UMTS

Synchronization

Codes

Channelization

Codes

Scrambling

Codes, UL

Scrambling

Codes, DL

Type

Gold Codes

Primary Synchronization

Codes (PSC) and

Secondary

Synchronization Codes

(SSC)

Orthogonal Variable

Spreading Factor

(OVSF) codes

sometimes called

Walsh Codes

Complex-Valued

Gold Code Segments

(long) or Complex-

Valued S(2) Codes

(short)

Pseudo Noise (PN)

codes

Complex-Valued

Gold Code

Segments

Pseudo Noise

(PN) codes

Length 256 chips 4-512 chips 38400 chips /

256 chips 38400 chips

Duration 66.67 s 1.04 s -

133.34 s 10 ms / 66.67 s 10 ms

Number of

codes

1 primary code / 16

secondary codes

spreading factor

4 ... 256 UL,

4 ... 512 DL

16,777,216

512 primary / 15

secondary for

each primary

code

Spreading No, does not change

bandwidth

Yes, increases

bandwidth

No, does not change

bandwidth

No, does not

change

bandwidth

Usage

To enable terminals to

locate and synchronize to

the cells' main control

channels

UL: to separate

physical data and

control data from same

terminal

DL: to separate

connection to different

terminals in a same

cell

Separation of terminal Separation of



WCDMA for UMTS Wiley

http://www.umtsworld.com/technology/codes.htm

3GPP TS 25.201, 25.213, 25.223

3g basic issue 1-3 ovsf code thai

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