hPUSCHEVM using with TDD uplink signals

Question

Reichmuth Kim 2020-11-12

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/645618-hpuschevm-using-with-tdd-uplink-signals

评论： Zhengguang Zhang 2023-7-5

Hello,

I try to use the function as described in Title to evaluate the EVM of an LTE UE Uplink signal in TDD. I tried to do it like the example "LT E Uplink EVM and In-Band Emissions Measurements" openExample('lte/UplinkEVMandInBandEmissionsExample')

I generated a signal over the lteRMCULTool and set the Duplex Mode to TDD. Result is that i´ve got EVM over 300% and a warning:

________

Warning: CRC failed on decoded data, using sliced received symbols, EVM may be inaccurate!

> In hPUSCHEVM_ (line 303)

In UplinkEVMandInBandEmissionsExample (line 111)

________

Why does´nt it work with TDD. Can somebody help me?

EDIT: Code as follows:

clear all; close all;
%%  Transmitter
% Set the seeds of random number generators used to 0
rng(0);
% UE Configuration, TS36.101 FRC
frc = lteRMCUL('A3-5');
frc.PUSCH.RVSeq = 0;    % Redundancy version
frc.TotSubframes = 10;  % Total number of subframes to generate
frc.DuplexMode = 'TDD';
% Create UE transmission with random PUSCH data
txWaveform = lteRMCULTool(frc,randi([0 1], frc.PUSCH.TrBlkSizes(1), 1));
%%  Impairment Modeling
% Model EVM with additive noise
scfdmaInfo = lteSCFDMAInfo(frc);        
txEVMpc = 1.2; % Desired transmit EVM in percent
evmModel = txEVMpc/(100*sqrt(double(scfdmaInfo.Nfft)))* ...
    complex(randn(size(txWaveform)),randn(size(txWaveform)))/sqrt(2);        
rxWaveform = txWaveform+evmModel;    
% Add frequency offset impairment to received waveform
foffset = 33.0;         % Frequency offset in Hertz
t = (0:length(rxWaveform)-1).'/scfdmaInfo.SamplingRate;
rxWaveform = rxWaveform.* exp(1i*2*pi*foffset*t);
% Add IQ offset
iqoffset = complex(0.01, -0.005);
rxWaveform = rxWaveform+iqoffset;
%%  Receiver
% Apply frequency estimation and correction for the purposes of performing
% timing synchronization
foffset_est = lteFrequencyOffset(frc, rxWaveform);
rxWaveformFreqCorrected = ...
    lteFrequencyCorrect(frc, rxWaveform, foffset_est);
% Synchronize to received waveform
offset = lteULFrameOffset(frc, frc.PUSCH, rxWaveformFreqCorrected);    
rxWaveform  = rxWaveform(1+offset:end,:);      
%% Perform Measurements
% Compute EVM and in-band emissions
[evmpusch, evmdrs, emissions, plots] = hPUSCHEVM(frc, rxWaveform); 
% Plot the absolute in-band emissions
if (~isempty(emissions.DeltaRB))
    hPUSCHEVMEmissionsPlot(emissions);
end