MATLAB实现MIMO系统的QRM-MLD检测器的软判决.zip

function [X_hat]=QRM_MLD_detecor(Y,H) % Input parameters % Y : received signal, nTx1 % H : Channel matrix, nTxnT % Output parameter % X_hat : estimated signal, nTx1 %MIMO-OFDM Wireless Communications with MATLAB�� Yong Soo Cho, Jaekwon Kim, Won Young Yang and Chung G. Kang %2010 John Wiley & Sons (Asia) Pte Ltd global QAM_table Q R Y_tilde NT M; % NT : Number of Tx antennas, M : Parameter M in M-algorithm QAM_table = [-3-3j, -3-j, -3+3j, -3+j, -1-3j, -1-j, -1+3j, -1+j, 3-3j, ... 3-j, 3+3j, 3+j, 1-3j, 1-j, 1+3j, 1+j]/sqrt(10); % QAM table [Q R] = qr(H); % QR-decomposition Y_tilde = Q'*Y; symbol_replica = zeros(NT,M,NT); % QAM table index for stage = 1:NT symbol_replica = stage_processing1(symbol_replica,stage); end X_hat = QAM_table(symbol_replica(:,1)); function[symbol_replica] = stage_processing1(symbol_replica,stage) % Input parameters % Y_tilde : Q'*Y % R : [Q R] = qr(H) % QAM_table : % symbol_replica : M candidate vectors % stage : stage number % M : parameter M in the M-algorithm % NT : number of Tx antennas % Output parameter % symbol_replica : M candidate vectors global NT M; if stage == 1; m = 1; else m = M; end symbol_replica_norm = calculate_norm(symbol_replica,stage); [symbol_replica_norm_sorted, symbol_replica_sorted] = sort_matrix(symbol_replica_norm); % sort in norm order, data is in a matrix form symbol_replica_norm_sorted = symbol_replica_norm_sorted(1:M); symbol_replica_sorted = symbol_replica_sorted(:,[1:M]); if stage>=2 for i=1:m symbol_replica_sorted([2:stage],i) = ... symbol_replica([1:stage-1],symbol_replica_sorted(2,i),(NT+2)-stage); end end if stage == 1 % In stage 1, size of symbol_replica_sorted is 2xM, the second row is not necessary symbol_replica([1:stage],:,(NT+1)-stage) = symbol_replica_sorted(1,:); else symbol_replica([1:stage],:,(NT+1)-stage) = symbol_replica_sorted; end function [symbol_replica_norm]=calculate_norm(symbol_replica,stage) % Input parameters % Y_tilde : Q'*Y % R : [Q R] = qr(H) % QAM_table : % symbol_replica : M candidate vectors % stage : stage number % M : M parameter in M-algorithm % NT : number of Tx antennas % Output parameter % symbol_replica_norm : norm values of M candidate vectors global QAM_table R Y_tilde NT M; if stage == 1; m = 1; else m = M; end stage_index = (NT+1)-stage; for i=1:m X_temp = zeros(NT,1); for a=NT:-1:(NT+2)-stage X_temp(a) = QAM_table(symbol_replica((NT+1)-a,i,stage_index+1)); end X_temp([(NT+2)-stage:(NT)]) = wrev(X_temp([(NT+2)-stage:(NT)])); % reordering Y_tilde_now = Y_tilde([(NT+1)-stage:(NT)]); % Y_tilde used in the current stage R_now = R([(NT+1)-stage:(NT)],[(NT+1)-stage:(NT)]); % R used in the current stage for k = 1:length(QAM_table) % norm calculation, % the norm values in the previous stages can be used, however, % we recalculate them in an effort to simplify the MATLAB code X_temp(stage_index) = QAM_table(k); X_now = X_temp([(NT+1)-stage:(NT)]); symbol_replica_norm(i,k) = norm(Y_tilde_now - R_now*X_now)^2; end end function [index_number] = find_vector(range,target); % Input parameters % target : target vector % range : the range of target vector % Output parameters % index_number : the index of range that corresponds to target for index_number=1:size(range,2) if range(:,index_number)==target, break; end end function [entry_sorted entry_index_sorted] = sort_matrix(matrix_form) % Input parameters % matrix_form : a matrix to be sorted % M : parameter M in M-algorithm % Output parameters % entry_sorted : increasingly ordered norm % entry_index_sorted : ordered QAM_table index [row_size,column_size] = size(matrix_form); flag=0; % flag = 1 ? the least norm is found vector_form=[]; entry_index_sorted =[]; for i = 1:row_size % matrix form ? vector form vector_form = vector_form matrix_form(i,:); end for m=1:row_size*column_size entry_min = min(vector_form); flag=0; for i = 1:row_size if flag==1, break; end for k = 1:column_size if flag==1, break; end entry_temp = matrix_form(i,k); if entry_min == entry_temp entry_index_sorted = entry_index_sorted [k; i]; entry_sorted(m) = entry_temp; vector_form((i-1)*column_size+k)=10000000; flag=1; end end end end