基于Alamouti 空间时间分组编码模拟瑞利衰落信道 BPSK 调制并计算误码率附matlab完整代码

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智能优化算法  神经网络预测 雷达通信  无线传感器

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⛄ 内容介绍

基于Alamouti提出的BPSK调制下空时分组码在Rayleigh衰落信道中的码性能原理,推导出高阶(M ary)调制下Rician衰落信道中空时分组码的符号差错率的最小距离球界,并进行计算机仿真分析了两信道下引入空时分组码的多天线系统中发射和接收天线的分集增益,发射天线数量的"地板效应"以及Rician因子K对符号差错性能的影响。

⛄ 完整代码

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% from Krishna Pillai.

%使用 Alamouti 空间时间分组编码以百分比瑞利衰落信道计算 BPSK 调制误码率的脚本

% Script for computing the BER for BPSK modulation in a

% Rayleigh fading channel with Alamouti Space Time Block Coding

% Two transmit antenna, 1 Receive antenna

clear

N = 10^6; % number of bits or symbols

Eb_N0_dB = [0:25]; % multiple Eb/N0 values

for ii = 1:length(Eb_N0_dB)

    % Transmitter

    ip = rand(1,N)>0.5; % generating 0,1 with equal probability

    s = 2*ip-1; % BPSK modulation 0 -> -1; 1 -> 0

    % Alamouti STBC 

    sCode = zeros(2,N);

    sCode(:,1:2:end) = (1/sqrt(2))*reshape(s,2,N/2); % [x1 x2  ...]

    sCode(:,2:2:end) = (1/sqrt(2))*(kron(ones(1,N/2),[-1;1]).*flipud(reshape(conj(s),2,N/2))); % [-x2* x1* ....]

    h = 1/sqrt(2)*[randn(1,N) + j*randn(1,N)]; % Rayleigh channel

    hMod = kron(reshape(h,2,N/2),ones(1,2)); % repeating the same channel for two symbols    

    n = 1/sqrt(2)*[randn(1,N) + j*randn(1,N)]; % white gaussian noise, 0dB variance

    % Channel and noise Noise addition

    y = sum(hMod.*sCode,1) + 10^(-Eb_N0_dB(ii)/20)*n;

    % Receiver

    yMod = kron(reshape(y,2,N/2),ones(1,2)); % [y1 y1 ... ; y2 y2 ...]

    yMod(2,:) = conj(yMod(2,:)); % [y1 y1 ... ; y2* y2*...]

    % forming the equalization matrix

    hEq = zeros(2,N);

    hEq(:,[1:2:end]) = reshape(h,2,N/2); % [h1 0 ... ; h2 0...]

    hEq(:,[2:2:end]) = kron(ones(1,N/2),[1;-1]).*flipud(reshape(h,2,N/2)); % [h1 h2 ... ; h2 -h1 ...]

    hEq(1,:) = conj(hEq(1,:)); %  [h1* h2* ... ; h2 -h1 .... ]

    hEqPower = sum(hEq.*conj(hEq),1);

    yHat = sum(hEq.*yMod,1)./hEqPower; % [h1*y1 + h2y2*, h2*y1 -h1y2*, ... ]

    yHat(2:2:end) = conj(yHat(2:2:end));

    % receiver - hard decision decoding

    ipHat = real(yHat)>0;

    % counting the errors

    nErr(ii) = size(find([ip- ipHat]),2);

end

simBer = nErr/N; % simulated ber

EbN0Lin = 10.^(Eb_N0_dB/10);

theoryBer_nRx1 = 0.5.*(1-1*(1+1./EbN0Lin).^(-0.5)); 

p = 1/2 - 1/2*(1+1./EbN0Lin).^(-1/2);

theoryBerMRC_nRx2 = p.^2.*(1+2*(1-p)); 

pAlamouti = 1/2 - 1/2*(1+2./EbN0Lin).^(-1/2);

theoryBerAlamouti_nTx2_nRx1 = pAlamouti.^2.*(1+2*(1-pAlamouti)); 

close all

figure

semilogy(Eb_N0_dB,theoryBer_nRx1,'bp-','LineWidth',2);

hold on

semilogy(Eb_N0_dB,theoryBerMRC_nRx2,'kd-','LineWidth',2);

semilogy(Eb_N0_dB,theoryBerAlamouti_nTx2_nRx1,'c+-','LineWidth',2);

semilogy(Eb_N0_dB,simBer,'mo-','LineWidth',2);

axis([0 25 10^-5 0.5])

grid on

legend('theory (nTx=1,nRx=1)', 'theory (nTx=1,nRx=2, MRC)', 'theory (nTx=2, nRx=1, Alamouti)', 'sim (nTx=2, nRx=1, Alamouti)');

xlabel('Eb/No, dB');

ylabel('Bit Error Rate');

title('BER for BPSK modulation with Alamouti STBC (Rayleigh channel)');

⛄ 运行结果

⛄ 参考文献

[1]张薇. 无线移动通信中空时分组编码的性能分析[D]. 兰州大学.

⛄ 完整代码

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