Reporting of Channel Quality Indicator (CQI) Conformance Test

NFrames = 10; SNRdB = 6.0;

enb = struct('RC','R.3');% Set up parameters of RMC R.3enb = lteRMCDL(enb); enb.CFI = 3;% Reconfigure Control Format Indicatorenb.OCNGPDSCHEnable ='On';% Enable OCNG for unallocated PDSCH REsenb.TotSubframes = 1;% Reconfigure for a single subframeenb.PDSCH.RVSeq = 0;% Disable HARQenb.PDSCH.CSIMode ='PUCCH 1-0';% Configure the CSI reporting modeenb.PDSCH.CSI ='On';% CSI scaling of soft bits

channel.Seed = 10;% Channel seedchannel.NRxAnts = 2;% 2 receive antennaschannel.DelayProfile ='EPA';% Delay profilechannel.DopplerFreq = 5.0;% Doppler frequencychannel.MIMOCorrelation ='High';% Multi-antenna correlationchannel.ModelType =“GMEDS';% Rayleigh fading model typechannel.NormalizeTxAnts ='On';% Normalize for transmit antennaschannel.NormalizePathGains ='On';% Normalize delay profile powerchannel.InitPhase ='Random';% Random initial phaseschannel.NTerms = 16;% Oscillators used in fading model% Set channel model sampling rateofdmInfo = lteOFDMInfo(enb); channel.SamplingRate = ofdmInfo.SamplingRate;

% Configure channel estimatorcec.PilotAverage ='UserDefined';% Type of pilot symbol averagingcec.FreqWindow = 9;% Frequency window size in REscec.TimeWindow = 9;% Time window size in REscec.InterpType ='Cubic';% 2D interpolation typecec.InterpWindow ='Centered';% Interpolation window typecec.InterpWinSize = 1;% Interpolation window size% Channel estimator behaviorperfectChanEstimator = true;

cqiDelay = 8;% subframes

% Initialize variables used for results recordingCQIReport = [];% reported CQI valuesSINRReport = [];% corresponding SINR valuesxaxis = [];% corresponding subframe numbers% For each CQI configuration (UE reported and median):forcqiConfig = 1:2if(cqiConfig==1) cqiConfigStr ='UE reported';elsecqiConfigStr ='median';endfprintf('\nSimulating with %s CQI at %gdB SNR for %d Frame(s)\n',...cqiConfigStr,SNRdB,NFrames);% Initialize CQI values: for UE reported, set to all ones; for median,% set to the median of the CQI values for the UE reported runif(cqiConfig==1) cqiBuffer = ones(1,cqiDelay);elsecqiBuffer = ones(1,cqiDelay)*medianCQI;end% Initialize variablesrng('default');% Default random number generator seedtotalCRC = [];% CRC values, used for throughput calculationtotalTBS = [];% TBS values, used for throughput calculationoffsets = 0;% Initialize frame offset value% For each subframe:forsubframeNo = 0:(NFrames*10-1)% Update subframe numberenb.NSubframe = mod(subframeNo,10);% Select CQI, reading the oldest value from the CQI buffercqiPtr = mod(subframeNo,cqiDelay); CQI = cqiBuffer(cqiPtr+1);% Select MCS according to CQI using TS36.101 Table A.4-1 CSI RMC% RC.1 FDD (MCS.1), which defines the relationship between CQI% indices and MCS indicesIMCSTable = [-1 0 0 2 4 6 8 11 13 16 18 21 23 25 27 27]; IMCS = IMCSTable(CQI+1);% Determine TBS and modulation order[ITBS,modulation] = lteMCS(IMCS); enb.PDSCH.Modulation = {modulation};if(mod(enb.NSubframe,5)==0) TBS = 0;elseTBS = double(lteTBS(size(enb.PDSCH.PRBSet,1),ITBS));endenb.PDSCH.TrBlkSizes(enb.NSubframe+1) = TBS;% Determine if a CQI update is required in this subframe, according% to reporting periodicity N_pd = 2ms and configuration index% cqi-pmi-ConfigurationIndex = 1 from TS36.101 Table 9.3.2.1.1-1cqiPeriod = 2;% periodicity N_pdcqiOffset = 1;% offset deriving from cqi-pmi-ConfigurationIndexcqiUpdate = (mod(subframeNo,cqiPeriod)==cqiOffset);% Establish if this subframe actually needs executed for PDSCH% reception, CQI estimation or initial timing offset estimation:if((TBS~=0 && subframeNo>=(cqiDelay+cqiOffset)) ||...(cqiConfig==1 && cqiUpdate) || subframeNo==0)% Generate random bits for the subframedata = randi([0 1],TBS,1);% Create OFDM resource grid containing RMC transmission and% perform OFDM modulation.txWaveform = lteRMCDLTool(enb,data);% The initialization time for channel modeling is set each% subframe to simulate a continuously varying channelchannel.InitTime = subframeNo/1000;% Pass data through the fading channel model.% An additional 25 samples are added to the end of the% waveform. These are to cover the range of delays expected% from the channel modeling (a combination of implementation% delay and channel delay spread)rxWaveform = lteFadingChannel(channel,...[txWaveform ; zeros(25,size(txWaveform,2))]);% Calculate noise gain including compensation for downlink% power allocationSNR = 10^((SNRdB-enb.PDSCH.Rho)/20);% Normalize noise power to take account of sampling rate, which% is a function of the IFFT size used in OFDM modulation, and% the number of antennasN0 = 1/(sqrt(2.0*enb.CellRefP*double(ofdmInfo.Nfft))*SNR);% Create additive white Gaussian noisenoise = N0*complex(randn(size(rxWaveform)),...randn(size(rxWaveform)));%添加情况下接收到的时域波形rxWaveform = rxWaveform + noise;% Perform synchronization% An offset within the range of delays expected from the% channel modeling (a combination of implementation delay and% channel delay spread) indicates successif(mod(subframeNo,10)==0) offset = lteDLFrameOffset(enb,rxWaveform);if(offset > 25) offset = offsets(end);endoffsets = [offsets offset];%#okendrxWaveform = rxWaveform(1+offset:end,:);% Perform OFDM demodulation on the received data to create% the received resource gridrxGrid = lteOFDMDemodulate(enb,rxWaveform);% Channel estimationif(perfectChanEstimator) chEstGrid =...lteDLPerfectChannelEstimate(enb,channel,offset); n = lteOFDMDemodulate(enb,noise(1+offset:end,:)); noiseEst = var(reshape(n,numel(n),1));else[chEstGrid,noiseEst] =...lteDLChannelEstimate(enb,enb.PDSCH,...cec、rxGrid);%#okend% If this subframe requires PDSCH reception:if(TBS~=0 && subframeNo>=(cqiDelay+cqiOffset))% Decode the PDSCHind = ltePDSCHIndices(enb,enb.PDSCH,enb.PDSCH.PRBSet); pdschRx = lteExtractResources(ind,rxGrid) *...(10^(-enb.PDSCH.Rho/20)); pdschChEst = lteExtractResources(ind,chEstGrid); [rxBits,rxSymbols] = ltePDSCHDecode(enb,enb.PDSCH,...pdschRx,pdschChEst,noiseEst);% Decode the DL-SCH[decbits,crc] = lteDLSCHDecode(enb,enb.PDSCH,TBS,rxBits);% Record the CRC and TBS values for final throughput% calculationtotalCRC = [totalCRC crc];%#oktotalTBS = [totalTBS TBS];%#okend% Update CQI:if(cqiConfig==1 && cqiUpdate)% Perform CQI selection[thisCQI,thisSINR] =...lteCQISelect(enb,enb.PDSCH,chEstGrid,noiseEst);% Feed the CQI value back to UE (in a buffer)cqiBuffer(cqiPtr+1) = thisCQI;% Record values for plottingCQIReport = [CQIReport thisCQI];%#okSINRReport = [SINRReport thisSINR];%#okxaxis = [xaxis subframeNo];%#okendend% For subframes where CQI was not updated, re-use the previous% value in the bufferif(cqiConfig==1 && ~cqiUpdate) cqiBuffer(cqiPtr+1) = cqiBuffer(mod(cqiPtr-1,cqiDelay)+1);endend% Display results for the current CQI configurationfprintf('\nResults with %s CQI:\n',cqiConfigStr); tputTotal = sum(totalTBS);if(cqiConfig==1)% Compute and display throughputtputUEReported = sum(totalTBS.*(1-totalCRC)); fprintf('Throughput: %d bits (%0.2f%%)\n',...tputUEReported,tputUEReported/tputTotal*100);% Compute and display BLERmeasuredBLER = mean(totalCRC); fprintf('BLER: %0.3f (requirement is >= 0.02)\n',measuredBLER);% Compute and display median CQImedianCQI = ceil(median(CQIReport)); fprintf('Median CQI: %d\n',medianCQI');% Compute and display proportion of CQI values% outside +/- 1 of the medianmeasuredAlpha = (sum(CQIReport<(medianCQI-1)) +...sum(CQIReport>(medianCQI+1)))/length(CQIReport)*100; fprintf(['Percentage of CQI indices outside +/- 1 of median:'...' %0.2f%% (requirement is >= 20%%)\n'],measuredAlpha);else% Compute and display throughputtputMedian = sum(totalTBS.*(1-totalCRC)); fprintf('Throughput: %d bits (%0.2f%%)\n',...tputMedian,tputMedian/tputTotal*100);% Compute and display throughput ratiomeasuredGamma = tputUEReported/tputMedian; fprintf(['Throughput ratio (gamma): %0.3f'...' (requirement is >= 1.05)'],measuredGamma);endend

figure; subplot(2,1,1); plot(xaxis,SINRReport,'rx-'); xlabel('Subframe number'); ylabel('Estimated SINR (dB)'); title('Estimated SINR versus subframe number'); holdon; subplot(2,1,2); plot(xaxis,CQIReport,'bo-'); xlabel('Subframe number'); ylabel('Selected CQI Index'); title('Selected CQI Index versus subframe number');