Documentation

ltePCFICHPRBS

PCFICH pseudorandom scrambling sequence

Syntax

  • seq = ltePCFICHPRBS(enb,n)
    example
  • seq = ltePCFICHPRBS(enb,n,mapping)
    example

Description

example

seq = ltePCFICHPRBS(enb,n) returns a vector containing the first n outputs of the physical control format indicator channel (PCFICH) scrambling sequence when initialized according to cell-wide settings structure, enb.

example

seq = ltePCFICHPRBS(enb,n,mapping) allows control over the format of the returned sequence, seq, through the mapping string.

Examples

collapse all

Scramble CFI Codeword

Scramble the CFI codeword.

Create cell-wide configuration structure, initialized to RMC R.14. Generate a CFI codeword and a pseudorandom scrambling sequence for the PCFICH the same length as the codeword.

enb = lteRMCDL('R.14');
cw = lteCFI(struct('CFI',2));
pcfichPrbsSeq = ltePCFICHPRBS(enb,length(cw));
size(pcfichPrbsSeq)
ans =

    32     1

Scramble the CFI codeword using the generated scrambling sequence.

scrambled = xor(pcfichPrbsSeq,cw);

Generate Signed PCFICH Pseudorandom Scrambling Sequence

Generate a signed pseudorandom scrambling sequence for the PCFICH. Each resource element (RE) in the PCFICH is QPSK-modulated, resulting in two bits-per-symbol mapping on each resource element.

Create cell-wide configuration structure, initialized to RMC R.14.

enb = lteRMCDL('R.14');
info = ltePCFICHInfo
pcfichPrbsSeq = ltePCFICHPRBS(enb,info.NRE*2,'signed');
size(pcfichPrbsSeq)
pcfichPrbsSeq(1:10)
info = 

    NREG: 4
     NRE: 16


ans =

    32     1


ans =

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

The scrambling sequence contains a vector of 32 signed ones.

Input Arguments

collapse all

enb — Cell-wide settingsscalar structure

Cell-wide settings, specified as a scalar structure. enb contains the following fields.

NCellID — Physical layer cell identity0...503

Physical layer cell identity, specified as a nonnegative scalar integer in the range of 0 to 503.

Data Types: double

NSubframe — Subframe numberpositive scalar integer

Subframe number, specified as a positive scalar integer greater than 0.

Data Types: double

Data Types: struct

n — Length of scrambling sequencepositive scalar integer

Length of scrambling sequence, specified as a positive scalar integer greater than 0. This argument determines the number of elements in the output vector, seq.

Data Types: double

mapping — Controls the format of the returned sequence'binary' (default) | 'signed'

Controls the format of the returned sequence, specified as either binary or signed. Valid formats are ('binary' (default), 'signed'). 'binary' maps true to 1 and false to 0, and 'signed' maps true to –1 and false to 1.

Data Types: char

Output Arguments

collapse all

seq — PCFICH pseudorandom scrambling sequencelogical column vector | numeric column vector

PCFICH pseudorandom scrambling sequence, returned as a logical column vector or a numeric column vector. This argument contains the first n outputs of the PCFICH scrambling sequence when initialized according to cell-wide settings structure, enb. If you set mapping to 'signed', the output is of data type double. Otherwise, it is of data type logical.

Data Types: logical | double

Introduced in R2014a

Was this topic helpful?