基于mimo的城市信道建模完整代码

以下是一个基于MIMO的城市信道建模完整代码示例：

%% 参数定义
numTxAntennas = 4;      % 发射天线数目
numRxAntennas = 2;      % 接收天线数目
numSubcarriers = 64;    % 子载波数目
numSymbols = 14;        % 符号数目
numPoints = 1000;       % 采样点数目

delaySpread = 30e-9;    % 时延扩展
maxDopplerShift = 100;  % 最大多普勒频移
numClusters = 6;        % 簇数
numSubpaths = 10;       % 子路径数
clusterDelaySpread = 2e-9;  % 簇时延扩展
subpathGain = -10;          % 子路径增益

%% 城市信道模型生成
chan = nrCDLChannel;
chan.NumTransmitAntennas = numTxAntennas;
chan.NumReceiveAntennas = numRxAntennas;
chan.SampleRate = 15.36e6;
chan.DelayProfile = 'CDL-C';
chan.DelaySpread = delaySpread;
chan.MIMOCorrelation = 'Low';
chan.TransmitCorrelationMatrix = eye(numTxAntennas);
chan.ReceiveCorrelationMatrix = eye(numRxAntennas);
chan.RandomStream = 'mt19937ar with seed';
chan.Seed = 73;

%% 生成频域响应
[txWaveform,~,gridDims] = helperCDLWaveformGenerator(numSubcarriers,numSymbols,numTxAntennas);
rxWaveform = zeros(numPoints,numRxAntennas);
for i = 1:numPoints
    [rxWaveform(i,:),pathGains] = chan(txWaveform(i,:));
end
rxWaveform = reshape(rxWaveform,numSubcarriers,numSymbols,numPoints,numRxAntennas);

%% 生成时域响应
maxClusterDelay = ceil(delaySpread*(numClusters-1)/clusterDelaySpread);
maxSubpathDelay = ceil(delaySpread*(numClusters-1)*(numSubpaths-1)/clusterDelaySpread);
numSamples = numSymbols*gridDims(1)*numSubcarriers;
timeWaveform = zeros(numSamples,numTxAntennas,numRxAntennas);
for i = 1:numPoints
    pathFilters = helperCDLPathFilters(pathGains{i},delaySpread,maxDopplerShift,maxClusterDelay,maxSubpathDelay,numTxAntennas,numRxAntennas,numSubpaths,clusterDelaySpread,subpathGain);
    timeWaveform = timeWaveform + helperCDLTimeDomainFilter(rxWaveform(:,:,:,i),pathFilters);  
end
timeWaveform = reshape(timeWaveform,numSymbols,gridDims(1),numSubcarriers,numTxAntennas,numRxAntennas);

%% 结果可视化
figure;
for txAnt = 1:numTxAntennas
    for rxAnt = 1:numRxAntennas
        subplot(numTxAntennas,numRxAntennas,(txAnt-1)*numRxAntennas+rxAnt);
        plot(squeeze(abs(timeWaveform(:,1,:,txAnt,rxAnt))));
        xlabel('采样点');
        ylabel('幅度');
        title(['TX Antenna ' num2str(txAnt) ' -> RX Antenna ' num2str(rxAnt)]);
    end
end

这段代码同样使用了MATLAB中的NR CDL信道模型生成器，生成符合城市衰落特性的多输入多输出信道模型。代码中包括了频域响应和时域响应的生成，以及结果的可视化。最后，代码会显示出每个发射天线到每个接收天线的时域响应。