LTE - Release 10 PUSCH Multiple Codeword Transmit and Receive Modeling

Posted 2020-12-17 zzyzz

Introduction

This example demonstrates the multicodeword transmission and reception in the uplink.

Parameters

% Generate configuration for FRC A3-2
frc = lteRMCUL(‘A3-2‘);

% UE configuration
frc.TotSubframes = 1;   % Total number of subframes
frc.NTxAnts = 2;        % Number of transmit antennas

% Update Physical Uplink Shared Channel (PUSCH) configuration for 2 identically configured codewords
frc.PUSCH.NLayers = 2;
frc.PUSCH.Modulation = repmat({frc.PUSCH.Modulation},1,2);
frc.PUSCH.RV = repmat(frc.PUSCH.RV,1,2);
frc.PUSCH.TrBlkSizes = repmat(frc.PUSCH.TrBlkSizes,2,1);

Encoding

This section sets up the transport blocks and the Uplink Control Information (UCI). This is then coded to generate the Uplink Shared Channel (UL-SCH). The diagram below shows the operations performed internally by lteULSCH.

 

 

% Set up the transport block sizes and data for both codewords
TBSs = frc.PUSCH.TrBlkSizes(:,frc.NSubframe+1); % transport block sizes
trBlks = {(randi([0 1], TBSs(1), 1)) (randi([0 1], TBSs(2), 1))}; % data

% Set up UCI contents
CQI = [1 0 1 0 0 0 1 1 1 0 0 0 1 1].‘;
RI  = [0 1 1 0].‘;
ACK = [1 0].‘;

% UL-SCH coding including UCI coding
cws = lteULSCH(frc,frc.PUSCH,trBlks,CQI,RI,ACK);

% PUSCH modulation is applied to the generated codewords
puschSymbols = ltePUSCH(frc,frc.PUSCH,cws);

Decoding

This section demodulates the PUSCH and applies channel decoding. The resulting UCI is then decoded to produce the received Channel Quality Indicator (CQI), Rank Indication (RI) and Acknowledgment (ACK).

% PUSCH demodulation
ulschInfo = lteULSCHInfo(frc,frc.PUSCH,TBSs,length(CQI),length(RI),length(ACK),‘chsconcat‘);    % Get UL-SCH information
llrs = ltePUSCHDecode(frc,ulschInfo,puschSymbols); % Decode PUSCH

% UL-SCH decoding
softBuffer = [];
[rxtrblks,crc,softBuffer] = lteULSCHDecode(frc,ulschInfo,TBSs,llrs,softBuffer);

% UCI decoding
[llrsData,llrsCQI,llrsRI,llrsACK] = lteULSCHDeinterleave(frc,ulschInfo,llrs);
rxCQI = lteCQIDecode(ulschInfo,llrsCQI);    % Decode CQI
rxRI = lteRIDecode(ulschInfo,llrsRI);       % Decode RI
rxACK = lteACKDecode(ulschInfo,llrsACK);    % Decode ACK

esults

The decoded CRC for both codewords is displayed. The transmitted and received CQI, RI and ACK bits are also shown.

CRCs:

Codeword 1: 0
Codeword 2: 0

CQI:
transmitted: 1  0  1  0  0  0  1  1  1  0  0  0  1  1
received   : 1  0  1  0  0  0  1  1  1  0  0  0  1  1

RI:
transmitted: 0  1  1  0
received   : 0  1  1  0

ACK:
transmitted: 1  0
received   : 1  0

Reference 

　　1. MathWorks

　　2. 3GPP TS 36.104