Documentation

ltePDCCHPRBS

PDCCH pseudorandom scrambling sequence

Syntax

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

Description

example

seq = ltePDCCHPRBS(enb,n) returns a column vector containing the first n outputs of the Physical Downlink Control Channel (PDCCH) scrambling sequence when initialized according to cell-wide settings structure, enb.

example

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

Examples

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Return Binary PDCCH Scrambling Sequence

Generate the first 7 outputs of the pseudorandom scrambling sequence for PDCCH in binary (default) format.

enb = lteRMCDL('R.0');
pdcchSeqBinary = ltePDCCHPRBS(enb,7)
pdcchSeqBinary =

     0
     0
     0
     0
     0
     0
     1

Scramble Random PDCCH Codeword

Scramble a random PDCCH codeword.

Create a cell-wide configuration structure, initialized to RMC R.0. Generate a codeword. Use MTot to determine the total number of bits associated with PDCCHs. Generate a PDCCH pseudorandom scrambling sequence the same length as the codeword.

enb = lteRMCDL('R.0');

pdcchInfo = ltePDCCHInfo(enb)
cw = randi([0,1],pdcchInfo.MTot,1);

pdcchSeq = ltePDCCHPRBS(enb,length(cw));
pdcchInfo = 

        NREG: 113
         NRE: 452
        NCCE: 12
    NREGUsed: 108
     NREUsed: 432
        MTot: 904
    NSymbols: 3

Scramble codeword with PDCCH PRBS.

scrambled = xor(pdcchSeq,cw);

Return Signed PDCCH Scrambling Sequence

Generate the first 7 outputs of the pseudorandom scrambling sequence for PDCCH in signed format.

enb = lteRMCDL('R.0');
pdcchSeqSigned = ltePDCCHPRBS(enb,7,'signed')
pdcchSeqSigned =

     1
     1
     1
     1
     1
     1
    -1

Input Arguments

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enb — Cell-wide settingsstructure

Cell-wide settings, specified as a structure. This argument contains the following fields.

NCellID — Physical layer cell identity0,...,503

Physical layer cell identity, specified as a nonnegative scalar integer from 0 through 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 — Number of elements in returned sequencenumeric scalar

Number of elements in returned sequence, seq, specified as a numeric scalar.

Data Types: double

mapping — Sequence format'binary' (default) | 'signed'

String that controls the format of the returned sequence seq. The string 'binary' maps true to 1 and false to 0. The string 'signed' maps true to –1 and false to 1.

Data Types: char

Output Arguments

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

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

Data Types: logical | double

Introduced in R2014a

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