使用时空块代码对 MIMO 系统执行最大似然均衡附matlab代码.zip

function [modulated_coded_symbols]=space_time_coding(modulated_symbols,code_name,rate,num_code,zero_padding) %% Space_time_coding % %Encode an input stream into a specified space time block code. % %Input: - modulated_symbols: a vector of symbols (if the length does not match with the STBC % structure you must use the zero_padding option) % - code_name: A string corresponding to the code name % ('SM','Alamouti','OSTBC3','STBC3','QOSTBC4','OSTBC4','STBC4','OSTBC5','OSTBC6','OSTBC7') % - rate: a string with the code rate '1/2','3/4','1','N' % - zero_padding (optionnal): if there is a 5th input and if the length does not % match with the space time bloc coding structure, than the modulated symbols are padded with zero. % %Output: modulated_coded_symbols % %Example: %>> C=space_time_coding([1+i,2+2*i],'Alamouti','1',1) %C = % 1.0000 + 1.0000i -2.0000 + 2.0000i % 2.0000 + 2.0000i 1.0000 - 1.0000i % %Remarks: %To obtain the code matrix, enter for example: %>>space_time_coding([1:4]+i*[1:4],'OSTBC4','3/4',1) % %To obtain the code length and the number of transmitter used by a STBC, %enter: size(space_time_coding(0,'OSTBC4','3/4',1,1)) % %Reference: % %[1] S.M Alamouti " A simple transmitter diversity scheme for wireless %communications" IEEE J.Select Areas Communication vol 16, %October 1998 %[2] V.Tarokh "Space Time BLock Codes from Orthogonal Designs" IEEE %Transactions on Information theory, vol 45, July 1999 %[3] G.Ganesan and P. Stoica "Space time Block Codes: A Maximum SNR %approach", IEEE Transactions on Information Theory, vol 47, may 2001. %[4] I. Jafarkhani: "A Quasi Orthogonal Space Time Block Code" %IEEE Transactions Letters on Communications, Vol. 49, %No.1, 2001 % % %Programmed by V. Choqueuse ([email protected]) modulated_coded_symbols=[]; switch code_name case 'SM' %% Spatial Multiplexing %% nb_emitters=str2num(rate); if(mod(length(modulated_symbols),nb_emitters)~=0) && (nargin==5) modulated_symbols(end+1:end+(nb_emitters-mod(length(modulated_symbols),nb_emitters)))=0; end if (mod(nb_emitters,1)==0) modulated_coded_symbols=reshape(modulated_symbols,nb_emitters,prod(size(modulated_symbols))/nb_emitters); else fprintf('Error: Spatial Mulitplexing -> code rate must be an integer\n'); end case 'Alamouti' if (strcmp(rate,'1')==1) %% Alamouti code %% %[1] S.M Alamouti " A simple transmitter diversity scheme for wireless %communications" IEEE J.Select Areas Communication vol 16, October 1998 if(mod(length(modulated_symbols),2)~=0) && (nargin==5) modulated_symbols(end+1:end+(2-mod(length(modulated_symbols),2)))=0; end symboles_reshape=reshape(modulated_symbols,2,length(modulated_symbols)/2); x1=[1 0]; x2=[0 1]; P1=[x1;x2]; P2=[-x2;x1]; P= [P1;conj(P2)]; modulated_coded_symbols=P*symboles_reshape; modulated_coded_symbols(3:4,:)=conj(modulated_coded_symbols(3:4,:)); modulated_coded_symbols=reshape(modulated_coded_symbols,2,prod(size(modulated_coded_symbols))/2); else fprintf('Error: Alamouti coding -> code rate must be 1\n'); end case 'OSTBC3' switch rate case '1/2' %% Tarokh OSTBC %[2] V.Tarokh "Space Time BLock Codes from Orthogonal Designs" IEEE %Transactions on Information theory, vol 45, July 1999 if(mod(length(modulated_symbols),4)~=0) && (nargin==5) modulated_symbols(end+1:end+(4-mod(length(modulated_symbols),4)))=0; end symboles_reshape=reshape(modulated_symbols,4,length(modulated_symbols)/4); x1=[1 0 0 0]; x2=[0 1 0 0]; x3=[0 0 1 0]; x4=[0 0 0 1]; P1=[x1;x2; x3]; P2=[-x2;x1;-x4]; P3=[-x3;x4;x1]; P4=[-x4;-x3;x2]; P=[P1;P2;P3;P4]; modulated_coded_symbols=[P;P]*symboles_reshape; modulated_coded_symbols(13:end,:)=conj(modulated_coded_symbols(13:end,:)); modulated_coded_symbols=reshape(modulated_coded_symbols,3,prod(size(modulated_coded_symbols))/3); case '3/4' switch num_code case 1 %% Ganesan STBC %[3] G.Ganesan and P. Stoica "Space time Block Codes: A Maximum SNR %approach", IEEE Transactions on Information Theory, vol 47, may 2001. if(mod(length(modulated_symbols),3)~=0) && (nargin==5) modulated_symbols(end+1:end+(3-mod(length(modulated_symbols),3)))=0; end symboles_reshape=reshape(modulated_symbols,3,length(modulated_symbols)/3); symboles_reshape_conj=conj(symboles_reshape); x1=[1 0 0]; x2=[0 1 0]; x3=[0 0 1]; x0=[0 0 0]; P1=[x1;x0;x0]; P2=[x0;x1;-x3]; P3=[x2;x0;x0]; P4=[-x3;x0;x0]; P=[P1;P2;P3;P4]; P1_conj=[x0;x0;-x2]; P2_conj=[x0;x0;x0]; P3_conj=[x0;x3;x1]; P4_conj=[x0;x2;x0]; P_conj=[P1_conj;P2_conj;P3_conj;P4_conj]; modulated_coded_symbols=P*symboles_reshape+P_conj*symboles_reshape_conj; modulated_coded_symbols=reshape(modulated_coded_symbols,3,prod(size(modulated_coded_symbols))/3); case 2 %% Ganesan STBC %[3] G.Ganesan and P. Stoica "Space time Block Codes: A Maximum SNR %approach", IEEE Transactions on Information %Theory, vol 47, may 2001. if(mod(length(modulated_symbols),3)~=0) && (nargin==5) modulated_symbols(end+1:end+(3-mod(length(modulated_symbols),3)))=0; end symboles_reshape=reshape(modulated_symbols,3,length(modulated_symbols)/3); symboles_reshape_conj=conj(symboles_reshape); x1=[1 0 0]; x2=[0 1 0]; x3=[0 0 1]; x0=[0 0 0]; P1=[x1;x2;x3]; P2=[x0;x0;x0]; P3=[x0;x0;x0]; P4=[x0;x0;x0]; P=[P1;P2;P3;P4]; P1_conj=[x0;x0;x0]; P2_conj=[-x2;x1;x0]; P3_conj=[x3;x0;-x1]; P4_conj=[x0;-x3;x2]; P_conj=[P1_conj;P2_conj;P3_conj;P4_conj]; modulated_coded_symbols=P*symboles_reshape+P_conj*symboles_reshape_conj; modulated_coded_symbols=reshape(modul