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WCDMA3G_IdScrambler


Description: Identification of scrambling code
Library: 3GPPFDD 10-99, Common Physical Channels
Class: SDFWCDMA3G_IdScrambler

Parameters

Name

Description

Default

Sym

Type

Range

ChipRate

chip rate of the system: Chip Rate 3.84M

Chip Rate 3.84M

 

enum

 

SampleRate

number of samples per chip

4

R

int

[1, 32]

NumberOfFrame

number of frames for statistics

1

Nf

int

[1, ∞)

Pin Inputs

Pin

Name

Description

Signal Type

1

in

received signal

complex

2

Spread

spreading code used in PCCPCH

int

3

Slot_T

indicator of slot synchronization timing

int

4

Frm_T

indicator of frame synchronization timing

int

5

ScrmbI

a group of eight candidate scrambling codes

multiple complex

6

IndexI

a group of eight scrambling code indices

multiple int

Pin Outputs

Pin

Name

Description

Signal Type

7

ScrmbO

identified scrambling code

complex

8

IndexO

identified scrambling code index

int

Notes/Equations
  1. This model is used to identify the scrambling code used in PCCPCH.
    Each firing, 38400 tokens of ScrmbO and one token of IndexO are produced when 38400 tokens of each ScrmbI signal, one token of each IndexI signal, 38400 × Nf × R tokens of in, 256 tokens of Spread, one token of Slot_T and one token of Frm_T are consumed.
  2. Because there are R samples per chip in the received signal, this model downsamples the received signal to chip sequence according to Slot_T and Frm_T. The Primary CCPCH is not transmitted during the first 256 chips of each slot; Primary SCH and Secondary SCH are transmitted during this period.
    Scrambling code identification is implemented by calculating the cross-correlation between the received signal in [ j ] and the candidate scrambling code Scrmbl [ j ]. Cross-correlation of the two complex-valued signals is defined as:

    This equation can be implemented using a tapped delay line structure illustrated in the following figure. P denotes the scope of correlation computation. ScrmbI and Spread are repeated with the period of 38400 and 256 tokens, respectively. This model includes a group of eight paralleled correlators.

    Correlator Structure

References
  1. 3GPP Technical Specification TS 25.211 V3.0.0, "Physical Channels and Mapping of Transport Channels onto Physical Channels (FDD)," October 1999.
  2. 3GPP Technical Specification TS 25.213 V3.0.0, "Spreading and Modulation (FDD)," October 1999.
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