Cedric Roux
56c66c09aa
Pre-ci test passed git-svn-id: http://svn.eurecom.fr/openair4G/trunk@4000 818b1a75-f10b-46b9-bf7c-635c3b92a50f
46 lines
953 B
Matlab
46 lines
953 B
Matlab
function [Hq, code_idx] = quantize_H(H,bits)
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% Hq = quantize_H(H)
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%
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% [1] Philips, "System-level simulation results for channel vector
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% quantisation feedback for MU-MIMO" 3gpp TSG RAN WG1 R1-063028, Nov. 2006
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[N_Tx, N_User] = size(H);
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N_codes = pow2(bits);
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for k=1:N_User
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normH(k) = norm(H(:,k));
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H(:,k) = H(:,k)./norm(H(:,k));
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end
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d = ifft(H,N_codes,1)*N_codes;
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%plot(abs(d));
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[m,code_idx] = max(abs(d));
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Hq = (exp(-1j*2*pi*(0:N_Tx-1)'*(code_idx-1)/N_codes))./sqrt(N_Tx);
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% Codebook = exp(-1j*2*pi*(0:N_Tx-1)'*(0:N_codes-1)/N_codes)./sqrt(N_Tx);
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%
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% d = zeros(N_codes,N_User);
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% for k=1:N_User
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% normH(k) = norm(H(:,k));
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% for i=1:N_codes
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% d(i,k) = Codebook(:,i)'*(H(:,k)./normH(k));
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% end
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% end
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%
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% plot(abs(d))
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%
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% [m,idx] = max(abs(d));
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%
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% Hq = Codebook(:,idx);
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% Hq has to have the same amplitude as H
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for i=1:N_User
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% Hq(:,i) = Hq(:,i).*d(idx(i),i).*normH(i);
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Hq(:,i) = Hq(:,i).*normH(i);
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end
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