基于MATLAB实现的lte物理层仿真信道建模，平台搭建 函数功能具有详细描述+使用说明文档.zip

function [channel_estimate] = LTE_channel_estimator(LTE_params,ChanMod, UE, rx_ref_symbols, RefSym, RefMapping, perfect_channel, sigma_n2, y_tx_assembled_genie, y_rx_assembled) % LTE channel estimator - to filter the output of the transmitter. % [chan_output] = LTE_channel_model(BS_output, SNR) % Author: Michal Simko, msimko@nt.tuwien.ac.at % (c) by INTHFT % www.nt.tuwien.ac.at % % input : ChanMod ... struct -> include info about filtering type, channel autocorrelation matrix % channel_estimation_method ... string -> type of channel estimation % channel_interpolation_method... string -> type of channel interpolation % rx_ref_symbols ... [ x ] matrix of recieved reference symbols % RefSym ... [ x ] matrix of transmitted reference symbols % RefMapping ... [ x ] logical matrix of positions of reference symbols % perfect_channel ... [ x ] coefficients of perfect channel % sigma_n2 ... [1x1] double noise estimate % output: channel_estimate ... [ x ] matrix of estimate of channel coefficients % % date of creation: 2009/04/06 % last changes: 2008/12/12 Simko % global LTE_params; %% Channel estimator channel_estimate = nan(size(perfect_channel)); interpolation = false; channel_estimation_method = UE.channel_estimation_method; channel_interpolation_method = UE.channel_interpolation_method; switch ChanMod.filtering case 'BlockFading' switch channel_estimation_method case 'corrMMSE' [position_freq,position_time] = find(RefMapping(:,:,1)); pilots_num = length(position_freq); H_ls_matrix = nan(pilots_num/2,ChanMod.nRX,ChanMod.nTX); for tt = 1:ChanMod.nTX for rr = 1:ChanMod.nRX H_ls_one_channel = rx_ref_symbols(:,:,tt,rr)./RefSym(:,:,tt); [position_freq,position_time] = find(RefMapping(:,:,tt)); %positons of reference symbols if(tt>2) %position = reshape(position_freq,length(position_freq)/2,2); %form the position of reference symbols to appropriate matrix [notused reference_mapping] = sort(position_freq); %find the real order of reference symbols in frequency H_ls_one_channel = reshape(H_ls_one_channel,length(position_freq),2); H_ls_one_channel(:,2) = []; else position = reshape(position_freq,length(position_freq)/2,2); %form the position of reference symbols to appropriate matrix [notused reference_mapping] = sort(position(:,1)); %find the real order of reference symbols in frequency H_ls_one_channel = reshape(H_ls_one_channel,length(position_freq)/2,2); end H_ls_one_channel = mean(H_ls_one_channel,2); H_ls_matrix(:,rr,tt) = H_ls_one_channel(reference_mapping); end end H_ls_vector = H_ls_matrix(:); channel_autocorrelation = UE.channel_autocorrelation_matrix; antenna_correlation = kron(squeeze(ChanMod.corrRX(1,:,:)) , squeeze(ChanMod.corrTX(1,:,:))); channel_autocorrelation_full = kron(antenna_correlation,channel_autocorrelation); permutation_matrix = zeros(LTE_params.Ntot*ChanMod.nTX*ChanMod.nRX); permutation_vector = 1:LTE_params.Ntot*ChanMod.nTX*ChanMod.nRX; pilot_pos = repmat(notused,ChanMod.nRX*ChanMod.nTX,1) + kron((0:(ChanMod.nRX*ChanMod.nTX-1))',ones(LTE_params.Ntot/3,1)*LTE_params.Ntot); pilots_num = length(pilot_pos); permutation_vector(pilot_pos) = []; permutation_vector = [pilot_pos;permutation_vector']; for pos_i = 1:LTE_params.Ntot*ChanMod.nRX*ChanMod.nTX permutation_matrix(pos_i,permutation_vector(pos_i)) = 1; end channel_autocorrelation_full_permutated = permutation_matrix * channel_autocorrelation_full * permutation_matrix'; channel_estimate_permutated = channel_autocorrelation_full_permutated(:,1:pilots_num)*inv( channel_autocorrelation_full_permutated(1:pilots_num,1:pilots_num) + sigma_n2*eye(pilots_num)) * H_ls_vector; channel_estimate_help = permutation_matrix'*channel_estimate_permutated; channel_estimate_help2 = reshape(channel_estimate_help,LTE_params.Ntot,ChanMod.nRX,ChanMod.nTX); channel_estimate(:,1,:,:) = channel_estimate_help2; channel_estimate = repmat(channel_estimate(:,1,:,:),[1,LTE_params.Nsub,1,1]); end end for tt = 1:ChanMod.nTX for rr = 1:ChanMod.nRX switch ChanMod.filtering case 'BlockFading' switch channel_estimation_method case 'PERFECT' channel_estimate = perfect_channel; % perfect channel knowledge case {'LS', 'GENIE'} %LS for block fading H_ls_one_channel = rx_ref_symbols(:,:,tt,rr)./RefSym(:,:,tt); [position_freq,position_time] = find(RefMapping(:,:,tt)); %positons of reference symbols if(tt>2) %position = reshape(position_freq,length(position_freq)/2,2); %form the position of reference symbols to appropriate matrix [notused reference_mapping] = sort(position_freq); %find the real order of reference symbols in frequency H_ls_one_channel = reshape(H_ls_one_channel,length(position_freq),2); H_ls_one_channel(:,2) = []; else position = reshape(position_freq,length(position_freq)/2,2); %form the position of reference symbols to appropriate matrix [notused reference_mapping] = sort(position(:,1)); %find the real order of reference symbols in frequency H_ls_one_channel = reshape(H_ls_one_channel,length(position_freq)/2,2); end H_ls_one_channel = mean(H_ls_one_channel,2); H_ls_one_channel = H_ls_one_channel(reference_mapping); interpolation = true; case 'MMSE' %first LS estimate on teh pilots positions H_ls_one_channel = rx_ref_symbols(:,:,tt,rr)./RefSym(:,:,tt); [position_freq,position_time] = find(RefMapping(:,:,tt)); %positons of reference symbols if(tt>2) %position = reshape(position_freq,length(position_freq)/2,2); %form the position of reference symbols to appropriate matrix pilots_num = length(position_freq); [notused reference_mapping] = sort(position_freq); %find the real order of reference symbols in frequency H_ls_one_channel = reshape(H_ls_one_channel,pilots_num,2); H_ls_one_channel(:,2) = []; else position = reshape(position_freq,length(position_freq)/2,2); %form the position of reference symbols to appropriate matrix pilots_num = length(position_freq)/2; [notused reference_mapping] = sort(position(:,1)); %find the real order of reference symbols in frequency H_ls_one_channel = reshape(H_ls_one_channel,pilots_num,2); end H_ls_one_channel = mean(H_ls_one_channel,2); H_ls_one_ch