Cedric Roux
56c66c09aa
Pre-ci test passed git-svn-id: http://svn.eurecom.fr/openair4G/trunk@4000 818b1a75-f10b-46b9-bf7c-635c3b92a50f
113 lines
3.6 KiB
Matlab
Executable File
113 lines
3.6 KiB
Matlab
Executable File
function [CAP] = capacity_SU_DSTTD(HH,SNR,normalize)
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% [CAP] = capacity_SU_MMSE(HH,SNR)
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%
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% This function calculates the capacity of the channel assuming DSTTD
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% coding at the transmitter and a ML receiver [1].
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% The channel gains are normalized, such that E(|h_{i,j}|^2) = 1,
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% where the avaraging is done over all snapshots and all frequencies.
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%
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% PARAMETERS
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% - CAP is the capacity values;
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% - HH is the input channel (M_Rx,M_Tx,fq,Channels)
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% - SNR is the considered SNR (Linear)
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% - normalize is a flag that indicates if the channel should be normalized
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%
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% Created: 25/04/2007 by delacerd@eurecom.fr
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% Modified last: 12/12/2007 by florian.kaltenberger@eurecom.fr
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%
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% [1] C. Mehlfuhrer, M. Rupp, C. F. Mecklenbrauker, Signals, Systems and Computers,
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% 2005. Conference Record of the Thirty-Ninth Asilomar Conference on (2005),
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% pp. 1258-1262.
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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[M_Rx,M_Tx,N_fq,N_channel] = size(HH);
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% fk: I don't think this code is correct.
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% tmp = zeros(N_fq,N_channel);
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% for kk = 1:N_channel,
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% tmp1 = 0;
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% for ii = 1:N_fq,
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% var1(:,:,ii,kk) = HH(:,:,ii,kk)*HH(:,:,ii,kk)';
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% tmp1 = tmp1 + norm(var1(:,:,ii,kk),'fro');
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% end
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% PP = tmp1/N_fq;
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% var1 = (M_Rx/PP) * var1;
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% for ii = 1:N_fq,
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% tmp(ii,kk) = abs(log2(det(diag(ones(M_Rx,1)) + SNR * var1(:,:,ii,kk))));
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% ForPDF(ii,kk) = trace(M_Tx*var1(:,:,ii,kk));
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% end
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% end
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if nargin<3
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normalize = 1;
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end
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if normalize
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% Normalization of H, such that E(|h_{i,j}|^2) = 1!
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var1 = complex(zeros(M_Rx,M_Rx,N_fq,N_channel));
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tmp = 0;
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for ii = 1:N_fq,
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for kk = 1:N_channel,
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% this is the squared frobenious norm of HH
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var1(:,:,ii,kk) = HH(:,:,ii,kk)*HH(:,:,ii,kk)';
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tmp = tmp + trace(var1(:,:,ii,kk));
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end
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end
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PP = real(tmp/(N_fq*N_channel*M_Rx*M_Tx))
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else
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PP = 1;
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end
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HH = HH./sqrt(PP);
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% now E(|h_{i,j}|^2) = 1!
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% Capacity estimation
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tmp = zeros(N_fq,N_channel);
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% ForPDF = zeros(N_fq,N_channel);
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n_p=1/SNR;
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if M_Tx == 4
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for ii = 1:N_fq,
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for kk = 1:N_channel,
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% conctruct the virtual channel matrix for DSTTD
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G = [HH(:,1,ii,kk) -HH(:,2,ii,kk) HH(:,3,ii,kk) -HH(:,4,ii,kk);
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conj(HH(:,2,ii,kk)) conj(HH(:,1,ii,kk)) conj(HH(:,4,ii,kk)) conj(HH(:,3,ii,kk))];
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% now we calculate the capacity using G, but dividing by 2 because
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% we have two channel uses per symbol
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tmp(ii,kk) = abs(log2(det(diag(ones(M_Tx,1)) + SNR/M_Tx * G * G')))./2;
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%tmp(ii,kk) = cap_MMSE(G,n_p)./2;
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end
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end
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elseif M_Tx == 2
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for ii = 1:N_fq,
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for kk = 1:N_channel,
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% conctruct the virtual channel matrix for DSTTD
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G = [HH(:,1,ii,kk) -HH(:,2,ii,kk);
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conj(HH(:,2,ii,kk)) conj(HH(:,1,ii,kk))];
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% now we calculate the capacity using G, but dividing by 2 because
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% we have two channel uses per symbol
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tmp(ii,kk) = abs(log2(det(diag(ones(M_Tx,1)) + SNR/M_Tx * G' * G)))./2;
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%tmp(ii,kk) = cap_MMSE(G,n_p)./2;
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end
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end
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else
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error('DSTTD only works with 4 Tx antennas');
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end
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% ForPDF = reshape(ForPDF,1,N_fq*N_channel);
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if N_channel == 1, % if we are analyzing one single frame the output is a value
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CAP = mean(tmp);
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% CAP = (tmp);
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else % if we are analyzing a sequence of frames, the output is a vector with all capacity values
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CAP = reshape(tmp,1,N_fq*N_channel);
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end
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