channel_est.m

一个UWB仿真程序包

%
%
%
function [channel_mask est_sig_energy] = channel_est(rx_down, fine_sync_index, G, ...
    pre_code, blocks_per_code_symbol,thld,PLOT_DEBUG)

code_len = length(pre_code);

%repeat code G times
code = repmat(pre_code,1,G)';

%create a matrix of the stuff to accumulate so that we can write the whole
%thing as a matrix product
if(length(rx_down)<fine_sync_index-1+ ...
        G*blocks_per_code_symbol*code_len) %we are too late -> sync failed
    channel_mask = [];
    est_sig_energy = 0;
else
    ch_mat = reshape(rx_down(fine_sync_index:fine_sync_index-1+ ...
        G*blocks_per_code_symbol*code_len), ...
        blocks_per_code_symbol,G*code_len);

    %accumulate
    channel_mask = ch_mat * code;

    channel_mask_temp = channel_mask;


    %apply thld
    channel_mask(channel_mask < thld) = 0;
    channel_mask(channel_mask >= thld) = 1;

    %calculate mean energy
    est_sig_energy = (channel_mask_temp' * channel_mask)./G;

%    if(PLOT_DEBUG)
%        figure
%        plot(channel_mask_temp)
%        hold on
%        plot(max(channel_mask_temp)*channel_mask,'r')
%        plot(thld*ones(1,length(channel_mask)),'m')
%    end
end
return;