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aaaa4564

木虫 (正式写手)

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注册: 2006-05-21
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专业: 通信理论与系统

[交流] 【求助】VBLAST系统的IPIC算法的流程

请教高手帮忙用maltab编程，以下给出了算法的流程！小弟急需用！各位行行好，帮帮忙！小弟先在此谢过了！
只要大家对vblast系统的zf,mmse算法了解的，基本上变量是一致的，只是处理干扰的过程不同。
各个变量基本是一致的！
以下是zf_osuc和mmse_osuc算法的程序，请各位参考以下！
我只需做2发2收的IPIC算法的信号检测！
function [BER]=vblast(Num,alg,modulation,corr,alpha)

%**************************************************************************
% This program implements vblast using perfect channel estimation for a 2x2
% system.
% z=vblast(Num,alg,modulation,corr,alpha) where
% Num-> number of runs
% alg -> algorithm.Choose from 'ZF' (for zero-forcing),'MM'(MMSE
% estimation),'ML'(maximum-likelihood decoding)
% modulation -> 'BPSK,'QPSK','16QAM','64QAM' (Note: for 'ML' algorithm only
% BPSK and QPSK exist and that too only for 2x2 configuration, as otherwise
% run time is too high.
% corr -> 1 for correlation at the receiver, 0 for no correlation
% alpha -> correlation coefficient value from 0 -> 1 and 0 in case corr =0;
% EXAMPLE: vblast(1000,'ZF','QPSK',1,0.5)plots ZF curve for QPSK with 0.5
% correlation coefficient at the receiver using 1000 Monte Carlo runs
%**************************************************************************

clc;
close all;
% identify bits for each type of modulation
switch modulation
case 'BPSK'
      BITS=1;

case 'QPSK'
      BITS=2;
case '16QAM'
      BITS=4;
case '64QAM'
      BITS=6;
end

% define SNR range
EbNo=[0:1:10];

%define plotting axis
SNR_axis=[];
BER_axis=[];

%set initial count
idx=1;

%define numbers of antennas
M=2;%rx antennas
N=1;%tx antennas

%parameters for wait bar
h = waitbar(0,'Please wait...');
wb=6.25;

%clear BER register
BER=[];

%commence SNR loop
for SNR=EbNo
errors=0;
%define standard deviation, sigma,  for noise
sigma=0.5/(sqrt(N)*10^(SNR/10));
      for iter=1:Num %commence iteration loop
%define a random Rayleigh channel
         H=(randn(M,N)+j*randn(M,N))/sqrt(2);
%exercise correlation option, if any
         if corr
            R=chol([1 alpha;alpha 1]);%cholesky factor of correlation matrix, i.e. 'R' square root of correlation matrix
            H=R*H; % R^0.5 *H -> correlation at receiver
         end
         H_save=H;%assign H to unalterable value

% modulated input data
         tx_bits=randn(N,BITS)>0;
         temp1=[];
            for i=1:N
                  d1=tx_modulate(tx_bits(i,

,modulation);
                  temp1=[temp1; d1];
            end
         d=temp1;
%AWGN noise
         AWGN_noise = sqrt(sigma)*(randn(M, N)+j*randn(M, N));
%receiver signal vector added to AWGN noise
         r = (H_save*d)/sqrt(N) + sqrt(sigma)*(randn(M, 1)+j*randn(M, 1));
%Zero-forcing algorithm
         if alg=='ZF'
%initialization
            G=pinv(H);
            [gk k0]=min(sum(abs(G).^2,2));

                  for m=1:N    % This FOR loop determines the ordering sequence k1 and determines the 'a' matrix.
                              %This is just one run,i.e. one for each H matrix.
                            %The 'a' matrix is automatically sorted as [a1 a2...aM]
                     k1(m)=k0;
                     w(m,

=G(k1(m),

;
y=w(m,

*r;
                     a(k1(m),1)=Q(y,modulation);
                     r = r - a(k1(m)) * H_save(:, k1(m));
                     H(:,k0)=zeros(M,1);
                     G=pinv(H);
                  for t=1:m
                     G(k1(
                     t),

=inf;
                     endm
                  [gk k0]=min(sum(abs(G).^2,2));
            end
%MMSE algorithm
         elseif alg=='MM'
  %initialisation
                  G=inv(H'*H+N/(10^(0.1*SNR))*eye(N))*H';
                  [gk k0]=min(sum(abs(G).^2,2));


                  for m=1:N    % This FOR loop determines the ordering sequence k1 and determines the 'a' matrix.
                              % This is just one run,i.e.one for each H matrix.The 'a' matrix is automatically sorted
                              % as [a1 a2...aM]

                     k1(m)=k0;
                     w(m,

=G(k1(m),

;
y=w(m,

*r;
                     a(k1(m),1)=Q(y,modulation);
                     r = r - a(k1(m)) * H_save(:, k1(m));
                     H(:,k0)=zeros(M,1);
                     G=inv(H'*H+N/(10^(0.1*SNR))*eye(N))*H';
                     for t=1:m
                        G(k1(t),

=inf;
                     end
                     [gk k0]=min(sum(abs(G).^2,2));
                  end

%count errors
         if BITS==1 %for BPSK modulation
            errors(iter) =  sum((sign(real(a))~=sign(real(d))));
         else %for QPSK,16QAM and 64QAM modulations
            errors(iter) =  sum((sign(real(a))~=sign(real(d))) | sign(imag(a))~=sign(imag(d)));
         end
      end %end of iteration loop Loop
BER(idx)=sum(errors)/(Num) ; % Calculate BER after completion of 'Num' runs
SER(idx)=BER(idx)*BITS; %calculate symbol error rate
idx=idx + 1; %increment count
waitbar(wb/100);
wb=wb+6.25;%increment wait bar
end %end of SNR loop
close(h);%terminate wait bar

SNR_axis=EbNo;
BER_axis=[BER_axis BER];
SER_axis=SER;

%plot BER
semilogy(SNR_axis,BER_axis,'b-');
xlabel('SNR [dB]');
ylabel('BER');
legend('')
%title('BER Plots');

%hold;

%plot SER
semilogy(SNR_axis,SER_axis,'b-o');
axis([0 10 1e-4 1]);
grid on;
legend('BER','SER');

hold off;
if alg=='MM'
alg='MMSE'
end
str=['VBLAST System-' '2x 2 ' alg ' Algorithm with ' modulation ' Modulation'];
set(gcf,'NumberTitle','off');
set(gcf,'Name',str);
grid on

[ Last edited by aaaa4564 on 2009-6-28 at 21:18 ]

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