WCDMA3G IdScrambler

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WCDMA3G_IdScrambler

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

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	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	Name	Description	Signal Type
7	ScrmbO	identified scrambling code	complex
8	IndexO	identified scrambling code index	int

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.
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

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