mimo系统中blast原理源代码

function output_frame = demodulation(input_modu, index) % demodulation for IEEE802.11a % Input: input_modu, complex values representing constellation points % index % Output: output_frame, output bit stream (data unit is one bit) % In this version, increase the quatilization levels into 8. % note: Matlab index starts from 1 QAM_input_I = real(input_modu); QAM_input_Q = imag(input_modu); output_frame = zeros(1,length(input_modu)*index); switch index case 1, BPSK_Demodu_I = [0 1]; %f(m)=(m+1)/2 + 1, so I=-1 ---> 1, I=1 ---> 2 idx = find(QAM_input_I>1); QAM_input_I(idx) = 1; idx = find(QAM_input_I<-1); QAM_input_I(idx) = -1; output_frame = BPSK_Demodu_I(round((QAM_input_I+1)/2) + 1); case 2, QPSK_Demodu_IQ = [0 1]; %f(m)=(m+1)/2 + 1, so I=-1 ---> 1, I=1 ---> 2 idx = find(QAM_input_I>1); QAM_input_I(idx) = 1; idx = find(QAM_input_I<-1); QAM_input_I(idx) = -1; idx = find(QAM_input_Q>1); QAM_input_Q(idx) = 1; idx = find(QAM_input_Q<-1); QAM_input_Q(idx) = -1; output_frame(1:2:end) = QPSK_Demodu_IQ(round((QAM_input_I+1)/2) + 1); output_frame(2:2:end) = QPSK_Demodu_IQ(round((QAM_input_Q+1)/2) + 1); case 4, QAM_16_Demodu_IQ = [0 1 3 2]; %f(m)=(m+3)/2 + 1, so I=-3 ---> 1, I=1 ---> 3 idx = find(QAM_input_I>3); QAM_input_I(idx) = 3; idx = find(QAM_input_I<-3); QAM_input_I(idx) = -3; idx = find(QAM_input_Q>3); QAM_input_Q(idx) = 3; idx = find(QAM_input_Q<-3); QAM_input_Q(idx) = -3; tmp = round((QAM_input_I+3)/2) + 1; output_frame(1:4:end) = bitget(QAM_16_Demodu_IQ(tmp),2); output_frame(2:4:end) = bitget(QAM_16_Demodu_IQ(tmp),1); tmp = round((QAM_input_Q+3)/2) + 1; output_frame(3:4:end) = bitget(QAM_16_Demodu_IQ(tmp),2); output_frame(4:4:end) = bitget(QAM_16_Demodu_IQ(tmp),1); case 6, QAM_64_Demodu_IQ = [0 1 3 2 6 7 5 4]; %f(m)=(m+7)/2 + 1, so I=-7 ---> 1, I=1 ---> 5 idx = find(QAM_input_I>7); QAM_input_I(idx) = 7; idx = find(QAM_input_I<-7); QAM_input_I(idx) = -7; idx = find(QAM_input_Q>7); QAM_input_Q(idx) = 7; idx = find(QAM_input_Q<-7); QAM_input_Q(idx) = -7; tmp = round((QAM_input_I+7)/2) + 1; output_frame(1:6:end) = bitget(QAM_64_Demodu_IQ(tmp),3); output_frame(2:6:end) = bitget(QAM_64_Demodu_IQ(tmp),2); output_frame(3:6:end) = bitget(QAM_64_Demodu_IQ(tmp),1); tmp = round((QAM_input_Q+7)/2) + 1; output_frame(4:6:end) = bitget(QAM_64_Demodu_IQ(tmp),3); output_frame(5:6:end) = bitget(QAM_64_Demodu_IQ(tmp),2); output_frame(6:6:end) = bitget(QAM_64_Demodu_IQ(tmp),1); end