1;
+% Symbol rate processing for tx side (modulator)
+
+function [tx_symb tx_bits prev_sym_tx] = tx_symbol_rate(sim_in, tx_bits, code_param, prev_sym_tx)
+ ldpc_code = sim_in.ldpc_code;
+ framesize = sim_in.framesize;
+ rate = sim_in.rate;
+ Nsymbrow = sim_in.Nsymbrow;
+ Nsymbrowpilot = sim_in.Nsymbrowpilot;
+ Nc = sim_in.Nc;
+ Npilotsframe = sim_in.Npilotsframe;
+ Ns = sim_in.Ns;
+ Nchip = sim_in.Nchip;
+ modulation = sim_in.modulation;
+ pilot = sim_in.pilot;
+
+ if ldpc_code
+ [tx_bits, tmp] = ldpc_enc(tx_bits, code_param);
+ end
+
+ % modulate --------------------------------------------
+
+ % organise symbols into a Nsymbrow rows by Nc cols
+ % data and parity bits are on separate carriers
+
+ tx_symb = zeros(Nsymbrow,Nc);
+
+ for c=1:Nc
+ for r=1:Nsymbrow
+ i = (c-1)*Nsymbrow + r;
+ tx_symb(r,c) = qpsk_mod(tx_bits(2*(i-1)+1:2*i));
+ end
+ end
+
+ % Optionally insert pilots, one every Ns data symbols
+
+ tx_symb_pilot = zeros(Nsymbrowpilot, Nc);
+
+ for p=1:Npilotsframe
+ tx_symb_pilot((p-1)*(Ns+1)+1,:) = pilot(p,:); % row of pilots
+ %printf("%d %d %d %d\n", (p-1)*(Ns+1)+2, p*(Ns+1), (p-1)*Ns+1, p*Ns);
+ tx_symb_pilot((p-1)*(Ns+1)+2:p*(Ns+1),:) = tx_symb((p-1)*Ns+1:p*Ns,:); % payload symbols
+ end
+ tx_symb = tx_symb_pilot;
+
+ % Optionally copy to other carriers (spreading)
+
+ for c=Nc+1:Nc:Nc*Nchip
+ tx_symb(:,c:c+Nc-1) = tx_symb(:,1:Nc);
+ end
+
+ % Optionally DQPSK encode
+
+ if strcmp(modulation,'dqpsk')
+ for c=1:Nc*Nchip
+ for r=1:Nsymbrowpilot
+ tx_symb(r,c) *= prev_sym_tx(c);
+ prev_sym_tx(c) = tx_symb(r,c);
+ end
+ end
+ end
+
+ % ensures energy/symbol is normalised when spreading
+
+ tx_symb = tx_symb/sqrt(Nchip);
+end
+
+
+% Init HF channel model from stored sample files of spreading signal ----------------------------------
+
+function [spread spread_2ms hf_gain] = init_hf_model(Fs, Rs, nsam)
+
+ % convert "spreading" samples from 1kHz carrier at Fs to complex
+ % baseband, generated by passing a 1kHz sine wave through PathSim
+ % with the ccir-poor model, enabling one path at a time.
+
+ Fc = 1000; M = Fs/Rs;
+ fspread = fopen("../raw/sine1k_2Hz_spread.raw","rb");
+ spread1k = fread(fspread, "int16")/10000;
+ fclose(fspread);
+ fspread = fopen("../raw/sine1k_2ms_delay_2Hz_spread.raw","rb");
+ spread1k_2ms = fread(fspread, "int16")/10000;
+ fclose(fspread);
+
+ % down convert to complex baseband
+ spreadbb = spread1k.*exp(-j*(2*pi*Fc/Fs)*(1:length(spread1k))');
+ spreadbb_2ms = spread1k_2ms.*exp(-j*(2*pi*Fc/Fs)*(1:length(spread1k_2ms))');
+
+ % remove -2000 Hz image
+ b = fir1(50, 5/Fs);
+ spread = filter(b,1,spreadbb);
+ spread_2ms = filter(b,1,spreadbb_2ms);
+
+ % discard first 1000 samples as these were near 0, probably as
+ % PathSim states were ramping up
+
+ spread = spread(1000:length(spread));
+ spread_2ms = spread_2ms(1000:length(spread_2ms));
+
+ % decimate down to Rs
+
+ spread = spread(1:M:length(spread));
+ spread_2ms = spread_2ms(1:M:length(spread_2ms));
+
+ % Determine "gain" of HF channel model, so we can normalise
+ % carrier power during HF channel sim to calibrate SNR. I imagine
+ % different implementations of ccir-poor would do this in
+ % different ways, leading to different BER results. Oh Well!
+
+ hf_gain = 1.0/sqrt(var(spread(1:nsam))+var(spread_2ms(1:nsam)));
+endfunction
+
+
% main test function
-function sim_out = ber_test(sim_in, modulation)
+function sim_out = ber_test(sim_in)
Fs = 8000;
+ modulation = sim_in.modulation;
verbose = sim_in.verbose;
framesize = sim_in.framesize;
Ntrials = sim_in.Ntrials;
Np = sim_in.Np; % number of pilots to use
Ns = sim_in.Ns; % step size between pilots
ldpc_code = sim_in.ldpc_code;
+ sim_in.rate = rate = sim_in.ldpc_code_rate;
bps = 2;
- Nsymb = framesize/bps;
- Nsymbrow = Nsymb/Nc;
- Npilotsframe = Nsymbrow/Ns;
- Nsymbrowpilot = Nsymbrow + Npilotsframe;
+
+ sim_in.Nsymb = Nsymb = framesize/bps;
+ sim_in.Nsymbrow = Nsymbrow = Nsymb/Nc;
+ sim_in.Npilotsframe = Npilotsframe = Nsymbrow/Ns;
+ sim_in.Nsymbrowpilot = Nsymbrowpilot = Nsymbrow + Npilotsframe;
printf("Each frame is %d bits or %d symbols, transmitted as %d symbols by %d carriers.",
framesize, Nsymb, Nsymbrow, Nc);
for c=1:Nc
pilot(:,c) = [ones(1,floor(Npilotsframe/2)) -ones(1,ceil(Npilotsframe/2))]';
end
+ sim_in.pilot = pilot;
tx_pilot_buf = [pilot; pilot; pilot];
% Init LDPC --------------------------------------------------------------------
ldpc;
- rate = sim_in.ldpc_code_rate;
mod_order = 4;
modulation2 = 'QPSK';
mapping = 'gray';
rate = 1;
end
- % Init HF channel model from stored sample files of spreading signal ----------------------------------
-
- % convert "spreading" samples from 1kHz carrier at Fs to complex
- % baseband, generated by passing a 1kHz sine wave through PathSim
- % with the ccir-poor model, enabling one path at a time.
-
- Fc = 1000; M = Fs/Rs;
- fspread = fopen("../raw/sine1k_2Hz_spread.raw","rb");
- spread1k = fread(fspread, "int16")/10000;
- fclose(fspread);
- fspread = fopen("../raw/sine1k_2ms_delay_2Hz_spread.raw","rb");
- spread1k_2ms = fread(fspread, "int16")/10000;
- fclose(fspread);
-
- % down convert to complex baseband
- spreadbb = spread1k.*exp(-j*(2*pi*Fc/Fs)*(1:length(spread1k))');
- spreadbb_2ms = spread1k_2ms.*exp(-j*(2*pi*Fc/Fs)*(1:length(spread1k_2ms))');
-
- % remove -2000 Hz image
- b = fir1(50, 5/Fs);
- spread = filter(b,1,spreadbb);
- spread_2ms = filter(b,1,spreadbb_2ms);
-
- % discard first 1000 samples as these were near 0, probably as
- % PathSim states were ramping up
-
- spread = spread(1000:length(spread));
- spread_2ms = spread_2ms(1000:length(spread_2ms));
-
- % decimate down to Rs
-
- spread = spread(1:M:length(spread));
- spread_2ms = spread_2ms(1:M:length(spread_2ms));
-
- % Determine "gain" of HF channel model, so we can normalise
- % carrier power during HF channel sim to calibrate SNR. I imagine
- % different implementations of ccir-poor would do this in
- % different ways, leading to different BER results. Oh Well!
-
- hf_gain = 1.0/sqrt(var(spread(1:Nsymbrow*Ntrials))+var(spread_2ms(1:Nsymbrow*Ntrials)));
+ [spread spread_2ms hf_gain] = init_hf_model(Fs, Rs, Nsymbrowpilot*Ntrials);
% Start Simulation ----------------------------------------------------------------
EsNo = 10^(EsNodB/10);
variance = 1/EsNo;
- if verbose > 1
+ if verbose > 1
printf("EsNo (dB): %f EsNo: %f variance: %f\n", EsNodB, EsNo, variance);
end
for nn = 1:Ntrials+2
if ldpc_code
- tx_bits = round(rand(1,framesize*rate));
- [tx_bits, tmp] = ldpc_enc(tx_bits, code_param);
+ tx_bits = round(rand(1,framesize*rate));
else
- tx_bits = round(rand(1,framesize));
+ tx_bits = round(rand(1,framesize));
end
+
+ [s_ch tx_bits prev_sym_tx] = tx_symbol_rate(sim_in, tx_bits, code_param, prev_sym_tx);
+
tx_bits_buf(1:framesize) = tx_bits_buf(framesize+1:2*framesize);
tx_bits_buf(framesize+1:2*framesize) = tx_bits;
- % modulate --------------------------------------------
-
- % organise symbols into a Nsymbrow rows by Nc cols
- % data and parity bits are on separate carriers
-
- tx_symb = zeros(Nsymbrow,Nc);
-
- for c=1:Nc
- for r=1:Nsymbrow
- i = (c-1)*Nsymbrow + r;
- tx_symb(r,c) = qpsk_mod(tx_bits(2*(i-1)+1:2*i));
- end
- end
-
- % Optionally insert pilots, one every Ns data symbols
-
- tx_symb_pilot = zeros(Nsymbrowpilot, Nc);
-
- for p=1:Npilotsframe
- tx_symb_pilot((p-1)*(Ns+1)+1,:) = pilot(p,:); % row of pilots
- %printf("%d %d %d %d\n", (p-1)*(Ns+1)+2, p*(Ns+1), (p-1)*Ns+1, p*Ns);
- tx_symb_pilot((p-1)*(Ns+1)+2:p*(Ns+1),:) = tx_symb((p-1)*Ns+1:p*Ns,:); % payload symbols
- end
- tx_symb = tx_symb_pilot;
-
- % Optionally copy to other carriers (spreading)
-
- for c=Nc+1:Nc:Nc*Nchip
- tx_symb(:,c:c+Nc-1) = tx_symb(:,1:Nc);
- end
-
- % Optionally DQPSK encode
-
- if strcmp(modulation,'dqpsk')
- for c=1:Nc*Nchip
- for r=1:Nsymbrowpilot
- tx_symb(r,c) *= prev_sym_tx(c);
- prev_sym_tx(c) = tx_symb(r,c);
- end
- end
- end
-
- % ensures energy/symbol is normalised when spreading
-
- s_ch = tx_symb/sqrt(Nchip);
-
% HF channel simulation ------------------------------------
hf_fading = ones(1,Nsymb);
sim_in.ldpc_code_rate = 0.5;
sim_in.ldpc_code = 1;
- sim_in.Ntrials = 20;
+ sim_in.Ntrials = 10;
sim_in.Esvec = 7;
sim_in.hf_sim = 1;
sim_in.hf_mag_only = 0;
-
- sim_qpsk_hf = ber_test(sim_in, 'qpsk');
+ sim_in.modulation = 'qpsk';
+
+ sim_qpsk_hf = ber_test(sim_in);
fep=fopen("errors_450.bin","wb"); fwrite(fep, sim_qpsk_hf.ldpc_errors_log, "short"); fclose(fep);
endfunction
projects / freetel-svn-tracking.git / commitdiff