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3GPPFDD_PRACHSprd



Description: Uplink PRACH spreading and scrambling
Library: 3GPPFDD, PhyCH Multiplexers & Coders
Class: SDF3GPPFDD_PRACHSprd
Derived From: 3GPPFDD_ULPhyCHBase

Parameters

Name

Description

Default

Unit

Type

Range

SpecVersion

version of specifications: Version_03_00, Version_12_00, Version_03_02

Version_12_00

 

enum

 

ScrambleCode

index of scramble code

0

 

int

[0:512] for downlink;
[0, 16777215] for uplink

PrmblSgntr

Preamble Signature

0

 

int

[0, 15]

Pin Inputs

Pin

Name

Description

Signal Type

1

CtrlIn

DPCCH part

int

2

GainD

gain factor of DPDCH

real

3

GainC

gain factor of DPCCH

real

4

SltFin

DPDCH slot format

int

5

Data

data

int

Pin Outputs

Pin

Name

Description

Signal Type

6

out

data

complex

Notes/Equations
  1. This model is used to spread and scramble message part of PRACH. The following figure illustrates the process.

    Spreading and Scrambling of PRACH Message Part
  2. The preamble signature s , 0 ≤ s ≤ 15, points to one of the 16 nodes in the code-tree that corresponds to channelization codes of length 16. The sub-tree below the specified node is used to spread the message part. The control part is spread with the channelization code cc of spreading factor 256 in the lowest branch of the sub-tree, i.e. cc = Cch,256,m where m = 16 × s + 15. The data part is spread by channelization code cd =Cch,SF,m and SF is the spreading factor used for the data part and m = SF × s/16.
  3. The n th PRACH message part scrambling code, denoted Sr-msg,n, where n = 0, 1, ... , 8191, is based on the long scrambling sequence as defined in [2].

References
  1. 3GPP Technical Specification TS 25.211 V3.10.0, Physical channels and mapping of transport channels onto physical channels (FDD), March 2003, Release 1999.
  2. 3GPP Technical Specification TS 25.213 V3.7.0, Spreading and modulation (FDD), March 2003, Release 1999.

    http://www.3gpp.org/ftp/Specs/2002-03/R1999/25_series/25213-370.zip

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