rx_diversity_proc.m

MATLAB Simulation of OFDM System

function [data_syms_out, pilot_syms_out] = rx_diversity_proc(freq_data_syms, freq_pilot_syms, ...
   channel_est, sim_options)
%  freq_data_syms:  n_rx_antennas*48*n_data_syms
%  data_syms_out:  48*n_data_syms
global sim_consts;

% 若没有采用接收分集，移出多余的维。需要注意后面的下标的引用的变化
freq_data_syms = squeeze(freq_data_syms);
freq_pilot_syms = squeeze(freq_pilot_syms);

% tx diversity  发射分集；2×2复分组空时码，即Radon-Hurwitz单位变换。
if sim_options.UseTxDiv
   % Radon-Hurwitz transmit diversity
   if ~sim_options.UseRxDiv
      freq_data_syms = rx_radon_hurwitz(freq_data_syms, channel_est(sim_consts.DataSubcPatt,:));
   elseif sim_options.UseRxDiv
      % Rx R-H performed to both receiver antennas
      freq_data_syms(1,:,:) = rx_radon_hurwitz(squeeze(freq_data_syms(1,:,:)),channel_est(sim_consts.DataSubcPatt,1:2));
      freq_data_syms(2,:,:) = rx_radon_hurwitz(squeeze(freq_data_syms(2,:,:)),channel_est(sim_consts.DataSubcPatt,3:4));
   end
end

% rx diversity  最大比例合并接收分集
if sim_options.UseRxDiv
   if ~sim_options.UseTxDiv
      freq_data_syms = rx_mr_combiner(freq_data_syms, channel_est(sim_consts.DataSubcPatt,:), sim_options);
      freq_pilot_syms = rx_mr_combiner(freq_pilot_syms, channel_est(sim_consts.PilotSubcPatt,:), sim_options);   
   elseif sim_options.UseTxDiv
      freq_data_syms = squeeze(freq_data_syms(1,:,:) + freq_data_syms(2,:,:));
      freq_pilot_syms = rx_mr_combiner(freq_pilot_syms, channel_est(sim_consts.PilotSubcPatt,:), sim_options);
   end
end

% no diversity  若无分集，则接收信号的估计值为R_e=R×conj(H)=S×H×conj(H)=S×abs（H)^2.
if (~sim_options.UseTxDiv) & (~sim_options.UseRxDiv)
   % Data symbols channel correction
   chan_corr_mat = repmat(channel_est(sim_consts.DataSubcPatt), 1, size(freq_data_syms,2));
   freq_data_syms = freq_data_syms.*conj(chan_corr_mat);
   chan_corr_mat = repmat(channel_est(sim_consts.PilotSubcPatt), 1, size(freq_pilot_syms,2));
   freq_pilot_syms = freq_pilot_syms.*conj(chan_corr_mat);
end

% 幅度归一化
%注意在对接收信号进行估计时，结果都是发射信号乘了一个|H|^2的形式，故需要归一化.
chan_sq_amplitude = sum(abs(channel_est(sim_consts.DataSubcPatt,:)).^2, 2);
chan_sq_amplitude_mtx = repmat(chan_sq_amplitude,1, size(freq_data_syms,2));

data_syms_out = freq_data_syms./chan_sq_amplitude_mtx;

chan_sq_amplitude = sum(abs(channel_est(sim_consts.PilotSubcPatt,:)).^2, 2);
chan_sq_amplitude_mtx = repmat(chan_sq_amplitude,1, size(freq_pilot_syms,2));
pilot_syms_out = freq_pilot_syms./chan_sq_amplitude_mtx;

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