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WCDMA3G_IdentifySCG


Description: Identification of scrambling code group
Library: 3GPPFDD 10-99, Common Physical Channels
Class: SDFWCDMA3G_IdentifySCG

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, ∞)

SCGNum

number of candidate SCGs

64

Ns

int

[1, 64]

Pin Inputs

Pin

Name

Description

Signal Type

1

in

received signal

complex

2

Slot_T

indicator of slot synchronization timing

int

3

SSCode

all candidate secondary synchronization codes responding to all candidate SCGs

multiple int

4

SCG

all candidate SCGs

multiple int

Pin Outputs

Pin

Name

Description

Signal Type

5

Frm_T

indicator of frame synchronization timing

int

6

Id_SCG

identified SCG

int

Notes/Equations
  1. This model is used to identify one scrambling code group from all candidate scrambling code groups (SCGs).
    Each firing, one token of Frm_T and one token of Id_SCG are produced when Nf × R × 38400 tokens of in, one token of Slot_T, 256 × 15 tokens of each SSCode signal and one token of each SCG signal are consumed. SSCode and SCG are multiple signals Ns.
  2. Because there are R samples per chip in the received signal, this model first downsamples the received signal to chip sequence according to Slot_T.
    Secondary synchronization code (SSC) is transmitted together with Primary synchronization code during the first 256 chips of each slot of Primary CCPCH. Primary CCPCH is not transmitted in this period. SSC code differs from one slot to another and has a period of one frame. There are 15 slots in one frame, so one SSC has 15 phases. The SSC starting position in the received signal is the frame synchronization timing. Each SSC corresponds to one SCG the cell uses.
    SCG identification is implemented by calculating the cross-correlation between the received signal in [ j ] and candidate SSCs SSCode [ j ]. The cross-correlation of a complex-valued signal and a real-valued sequence is defined as:

    This equation can be implemented using a structure of tapped delay line illustrated in the following figure. P denotes the scope of correlation computation. SSCode is repeated with the period of 256 × 15 tokens.This model includes a group of 15 × Ns 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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