init_data_signal.m

source Matlab traites the UWB

% Return data_signal: upsampled, pulse shaped and channel filtered
% version of the data bit
%

function [burst, compound_channel, Lb] ...
    = init_data_signal(FS_CONT, PACKET_LENGTH, ...
                       TC,BURST_LENGTH,SYMBOL_LENGTH, ...
                       ths, scrambling, samples, ...
                       channel_p)


% $$$ %
% $$$ %
% $$$ clear all;
% $$$ %
% $$$ % Necessary path
% $$$ addpath ./rng;
% $$$ addpath ../src/channel;
% $$$ 
% $$$ % Some parameters
% $$$ PLOT_DEBUG  = 0;
% $$$ FS_CONT = 10e9;
% $$$ PACKET_LENGTH = 3;%127*8;
% $$$ % Physical layer
% $$$ TC = 2e-9; % Chip length in seconds
% $$$ %BURST_LENGTH = 4; % LPRF, in chip
% $$$ BURST_LENGTH = 16; % HPRF, in chip
% $$$ SYMBOL_LENGTH = 512; % In chip
% $$$ NHOP = SYMBOL_LENGTH/BURST_LENGTH/4;
% $$$ TF = SYMBOL_LENGTH*TC;
% $$$ fprintf('Number of data bit = %d\n',PACKET_LENGTH);
% $$$ fprintf('Number of hops available = %d\n',NHOP);
% $$$ % Multipath channel
% $$$ CH_MODEL = 1;
% $$$ CH_ATT_THLD_DB = 30; %rays with bigger attenuation are considered 0
% $$$ CH_RNG_SEED = sum(100*clock);

PLOT_DEBUG = 0;


%TF = SYMBOL_LENGTH*TC;
fprintf('Number of data bit = %d\n',PACKET_LENGTH);
fprintf('Sampling freq.: %.2e\n',FS_CONT);
fprintf('Samples: %d %d %d %d\n', ...
	samples.chip,samples.burst, ...
	samples.symbol,samples.packet);

fs_cont_GHz = FS_CONT / 1e9;
% Get the pulse
[monopulse,t] = get_monopulse(1,channel_p.chip_span,...
    channel_p.pulse_width,TC,samples.chip);
monopulse = monopulse/norm(monopulse);
fprintf('Norm of the pulse = %.4f\n',norm(monopulse));
if(PLOT_DEBUG)
    figure;
    plot(t,monopulse);
end

% $$$ % determine pulse -10dB bandwidth
% $$$ threshold_dB = -10;
% $$$ [Ess,f_high,f_low,BW] = ...
% $$$              cp0702_bandwidth(monopulse,1/FS_CONT,threshold_dB);
% $$$ fprintf('-10dB BW of the pulse = %d [Hz]\n',BW);

% Multipath channel
[channel_cont, channel_discr] = mex_channel(channel_p.model, ...
                                            fs_cont_GHz, ...
                                            channel_p.thld, ...
                                            channel_p.seed);
uoi_channel_discr = channel_discr(:,4)';
uoi_channel_discr = uoi_channel_discr ./ norm(uoi_channel_discr);
fprintf('Norm of the cir = %.4f\n',norm(uoi_channel_discr));

% Calculate the compound channel of pulse shape and channel impulse response
% response
fprintf('Calculate the compound channel\n');
compound_channel = conv(uoi_channel_discr,monopulse);
%compound_channel = compound_channel ./ (norm(compound_channel)*BURST_LENGTH);
compound_channel = compound_channel ./ norm(compound_channel);
fprintf('Norm of the compound channel = %.4f\n',norm(compound_channel));
if(PLOT_DEBUG)
    figure;
    plot(compound_channel);
end

% Create the sequence of bursts
fprintf('Create the burst sequence\n');
[burst,Lb] = get_burst_sequence(compound_channel, ...
                                scrambling, ...
                                samples.chip, ...
                                BURST_LENGTH,PACKET_LENGTH);
%burst = burst ./ norm(burst);
fprintf('Norm of the burst sequence = %.4f\n',norm(burst));
if(PLOT_DEBUG)
    figure;
    plot(burst);
end

return;