贝尔实验室分层空时码-迫零算法-CD概要.doc

贝尔实验室分层空时码接收结构分析 --迫零算法 numOfBlk = 1e6; qamOrder = 16; SNRdB = 6:1:30; errRate = zeros(size(SNRdB)) for i = 1 : length(SNRdB) txData = randint(numOfBlk*2,1,qamOrder); temp = reshape(txData,numOfBlk,2); temp = qammod(temp,qamOrder); H = 1/sqrt(2) * (randn(numOfBlk,2) + sqrt(-1)*randn(numOfBlk,2)); txMod(:,1) = H(:,1).* 1/sqrt(2).*temp(:,1) + H(:,2).* 1/sqrt(2).*temp(:,2) ; txMod(:,2) = -H(:,1).*(1/sqrt(2).*temp(:,2)). + H(:,2).*(1/sqrt(2).*temp(:,1)). ; txMod = awgn(txMod,SNRdB(i),measured); temp(:,1) = sqrt(2)*(H(:,1). .* txMod(:,1) + H(:,2) .* txMod(:,2).)./(abs(H(:,1)).^2 + abs(H(:,2)).^2); temp(:,2) = sqrt(2)*(H(:,2). .* txMod(:,1) - H(:,1) .* txMod(:,2).)./(abs(H(:,1)).^2 + abs(H(:,2)).^2); rxData(:,1) = qamdemod(temp(:,1),qamOrder); rxData(:,2) = qamdemod(temp(:,2),qamOrder); [numErr errRate(i)] = symerr(rxData,reshape(txData,numOfBlk,2)); end f1 = figure(1); semilogy(SNRdB,errRate,[b,-,O]); xlabel(SNR in dB); ylabel(Symbol Error Rate); for i = 1 : length(SNRdB) temp = qammod(txData,qamOrder); H = 1/sqrt(2) * (randn(numOfBlk*2,1) + sqrt(-1)*randn(numOfBlk*2,1)); txMod = H.*temp; txMod = awgn(txMod,SNRdB(i),measured); temp = txMod./H; rxData = qamdemod(temp,qamOrder); [numErr errRate(i)] = symerr(rxData,txData); end figure(1); hold on semilogy(SNRdB,errRate,[k,:,d]); xlabel(SNR in dB); ylabel(Symbol Error Rate); title([SER evaluation of , num2str(qamOrder),QAM Modulation based on Alamouti STC]) legend(With Alamouti Code 2x1 channl,No STC 1x1 channl) grid on [摘要] 分层空时编码技术是提高无线信道传输速率和容量的一种非常有效的方法。在无需提高信号发射功率和额外增加带宽的情况下就可以大幅度的提高系统容量。但是，分层空时编码无法获得最大分集增益，所以接收端在恢复信号时选用的译码算法对系统性能至关重要。在平坦瑞利衰落环境下，本文首先对MIMO（Multiple Input Multiple Output，MIMO）的信道模型和容量进行分析，重点研究了它的容量仿真方法。在此基础上，研究了贝尔实验室分层空时（Bell Laboratories layered Space-Time，BLAST）的发射和接收结构，掌握了三种分层空时编码，包括水平分层（Horizontal Bell Laboratories Layered Sp