fake_estimate_channel.m

一个UWB仿真程序包

%
% 
% TC
% FS_CONT
% L
% preamble_code
% CODE_ID
% compound_channel
%
function [channel_mask] = ...
    fake_estimate_channel(TC,FS_CONT,samples,...
                          L,preamble_code,CODE_ID,...
                          compound_channel,...
                          T_INT,N_INT,...
                          s2,B)

G_EST         = 8;

stop_samples = G_EST*L*length(preamble_code)*TC*FS_CONT;

tx_bit        = [];
ths           = [];
scrambling    = [];
symbol_start  = [];
DATA_LENGTH   = 0;
RSCODE        = 0;
PACKET_LENGTH = 0;
BURST_LENGTH  = 0;
SYMBOL_LENGTH = 0;
ch_len        = length(compound_channel);
chip_span     = 0.5;

%
fprintf('Create a fake preamble\n');
preamble_uoi = create_packet(1,stop_samples,...
                             compound_channel,...
                             ch_len,chip_span,...
                             tx_bit,ths,scrambling,symbol_start,...
                             CODE_ID,L,TC,FS_CONT,...
                             DATA_LENGTH,RSCODE,PACKET_LENGTH,...
                             BURST_LENGTH,SYMBOL_LENGTH,...
                             samples,0);

% Add some noise
preamble_uoi = preamble_uoi + ...
    get_noise(length(preamble_uoi),s2,samples.chip,TC,FS_CONT,B);


% Energy receiver
[preamble_down,samples_per_tint] = ...
    ed_receiver(preamble_uoi,T_INT,FS_CONT,N_INT,0);


% Compute the threshold for the channel mask
fprintf('Compute the threshold for the channel mask\n');
THLD_PROBA            = 0.9999; %threshold for correlation peaks
non_zero_code_symbols = sum(abs(preamble_code));

%fprintf('Noise floor = %.2f\n',s2*(T_INT*2*B)*N_INT*G_EST* ...
%        non_zero_code_symbols);
%fprintf('Stuff = %.2f\n',s2*(T_INT*2*B)*N_INT);

est_thld = s2*chi2inv(THLD_PROBA, ...
                      (T_INT*2*B)*N_INT*G_EST*non_zero_code_symbols);
%est_thld = 0;

%fprintf('Threshold = %.2f\n',est_thld);
% Estimate the channel
fine_sync_index        = 1;
blocks_per_code_symbol = 16;

[channel_mask est_sig_energy] = ...
    channel_est(preamble_down, fine_sync_index, G_EST, ...
                preamble_code, blocks_per_code_symbol,est_thld,0);

fprintf('Channel mask = [');
fprintf('%d ',channel_mask);
fprintf(']\n');