-% test_foff.m
-% David Rowe April 2015
-%
-% Octave script for testing the cohpsk freq offset estimator
-
-graphics_toolkit ("gnuplot");
-more off;
-
-cohpsk;
-fdmdv;
-autotest;
-
-rand('state',1);
-randn('state',1);
-
-
-% Core function for testing frequency offset estimator. Performs one test
-
-function sim_out = freq_off_est_test(sim_in)
- global Nfilter;
- global M;
-
- Rs = 50;
- Nc = 4;
- Nd = 2;
- framesize = 32;
- Fs = 8000;
- Fcentre = 1500;
-
- afdmdv.Nsym = 2;
- afdmdv.Nt = 3;
-
- afdmdv.Fs = 8000;
- afdmdv.Nc = Nd*Nc-1;
- afdmdv.Rs = Rs;
- afdmdv.M = afdmdv.Fs/afdmdv.Rs;
- afdmdv.tx_filter_memory = zeros(afdmdv.Nc+1, Nfilter);
- afdmdv.Nfilter = Nfilter;
- afdmdv.gt_alpha5_root = gen_rn_coeffs(0.5, 1/Fs, Rs, afdmdv.Nsym, afdmdv.M);
- afdmdv.Fsep = 75;
- afdmdv.phase_tx = ones(afdmdv.Nc+1,1);
- freq_hz = afdmdv.Fsep*( -Nc*Nd/2 - 0.5 + (1:Nc*Nd) );
- afdmdv.freq_pol = 2*pi*freq_hz/Fs;
- afdmdv.freq = exp(j*afdmdv.freq_pol);
- afdmdv.Fcentre = 1500;
-
- afdmdv.fbb_rect = exp(j*2*pi*Fcentre/Fs);
- afdmdv.fbb_phase_tx = 1;
- afdmdv.fbb_phase_rx = 1;
- afdmdv.phase_rx = ones(afdmdv.Nc+1,1);
-
- nin = M;
-
- P = afdmdv.P = 4;
- afdmdv.Nfilter = afdmdv.Nsym*afdmdv.M;
- afdmdv.rx_filter_mem_timing = zeros(afdmdv.Nc+1, afdmdv.Nt*afdmdv.P);
- afdmdv.Nfiltertiming = afdmdv.M + afdmdv.Nfilter + afdmdv.M;
- afdmdv.rx_filter_memory = zeros(afdmdv.Nc+1, afdmdv.Nfilter);
-
- acohpsk = standard_init();
- acohpsk.framesize = framesize;
- acohpsk.ldpc_code = 0;
- acohpsk.ldpc_code_rate = 1;
- acohpsk.Nc = Nc;
- acohpsk.Rs = Rs;
- acohpsk.Ns = 4;
- acohpsk.Nd = Nd;
- acohpsk.modulation = 'qpsk';
- acohpsk.do_write_pilot_file = 0;
- acohpsk = symbol_rate_init(acohpsk);
- acohpsk.Ncm = 10*acohpsk.Nsymbrowpilot*M;
- acohpsk.coarse_mem = zeros(1,acohpsk.Ncm);
- acohpsk.Ndft = 2^(ceil(log2(acohpsk.Ncm)));
-
- ch_fdm_frame_buf = zeros(1, 2*acohpsk.Nsymbrowpilot*M);
-
- frames = sim_in.frames;
- EsNodB = sim_in.EsNodB;
- foff = sim_in.foff;
- dfoff = sim_in.dfoff;
- fading_en = sim_in.fading_en;
-
- EsNo = 10^(EsNodB/10);
- hf_delay_ms = 2;
- phase_ch = 1;
-
- rand('state',1);
- tx_bits_coh = round(rand(1,framesize*10));
- ptx_bits_coh = 1;
- [spread spread_2ms hf_gain] = init_hf_model(Fs, Fs, frames*acohpsk.Nsymbrowpilot*afdmdv.M);
-
- hf_n = 1;
- nhfdelay = floor(hf_delay_ms*Fs/1000);
- ch_fdm_delay = zeros(1, acohpsk.Nsymbrowpilot*M + nhfdelay);
-
- sync = 0; next_sync = 1;
- sync_start = 1;
- freq_offset_log = [];
- sync_time_log = [];
- ch_fdm_frame_log = [];
- ch_symb_log = [];
- tx_fdm_frame_log = [];
-
- for f=1:frames
-
- acohpsk.frame = f;
-
- %
- % Mod --------------------------------------------------------------------
- %
-
- tx_bits = tx_bits_coh(ptx_bits_coh:ptx_bits_coh+framesize-1);
- ptx_bits_coh += framesize;
- if ptx_bits_coh > length(tx_bits_coh)
- ptx_bits_coh = 1;
- end
-
- [tx_symb tx_bits] = bits_to_qpsk_symbols(acohpsk, tx_bits, [], []);
-
- tx_fdm_frame = [];
- for r=1:acohpsk.Nsymbrowpilot
- tx_onesymb = tx_symb(r,:);
- [tx_baseband afdmdv] = tx_filter(afdmdv, tx_onesymb);
- [tx_fdm afdmdv] = fdm_upconvert(afdmdv, tx_baseband);
- tx_fdm_frame = [tx_fdm_frame tx_fdm];
- end
- tx_fdm_frame_log = [tx_fdm_frame_log tx_fdm_frame];
-
- %
- % Channel --------------------------------------------------------------------
- %
-
- ch_fdm_frame = zeros(1,acohpsk.Nsymbrowpilot*M);
- for i=1:acohpsk.Nsymbrowpilot*M
- foff_rect = exp(j*2*pi*foff/Fs);
- foff += dfoff;
- phase_ch *= foff_rect;
- ch_fdm_frame(i) = tx_fdm_frame(i) * phase_ch;
- end
- phase_ch /= abs(phase_ch);
-
- if fading_en
- ch_fdm_delay(1:nhfdelay) = ch_fdm_delay(acohpsk.Nsymbrowpilot*M+1:nhfdelay+acohpsk.Nsymbrowpilot*M);
- ch_fdm_delay(nhfdelay+1:nhfdelay+acohpsk.Nsymbrowpilot*M) = ch_fdm_frame;
-
- for i=1:acohpsk.Nsymbrowpilot*M
- ahf_model = hf_gain*(spread(hf_n)*ch_fdm_frame(i) + spread_2ms(hf_n)*ch_fdm_delay(i));
- ch_fdm_frame(i) = ahf_model;
- hf_n++;
- end
- end
-
- % each carrier has power = 2, total power 2Nc, total symbol rate NcRs, noise BW B=Fs
- % Es/No = (C/Rs)/(N/B), N = var = 2NcFs/NcRs(Es/No) = 2Fs/Rs(Es/No)
-
- variance = 2*Fs/(acohpsk.Rs*EsNo);
- uvnoise = sqrt(0.5)*(randn(1,acohpsk.Nsymbrowpilot*M) + j*randn(1,acohpsk.Nsymbrowpilot*M));
- noise = sqrt(variance)*uvnoise;
-
- ch_fdm_frame += noise;
- ch_fdm_frame_log = [ch_fdm_frame_log ch_fdm_frame];
-
- %
- % Try to achieve sync --------------------------------------------------------------------
- %
-
- % store two frames so we can rewind if we get a good candidate
-
- ch_fdm_frame_buf(1:acohpsk.Nsymbrowpilot*M) = ch_fdm_frame_buf(acohpsk.Nsymbrowpilot*M+1:2*acohpsk.Nsymbrowpilot*M);
- ch_fdm_frame_buf(acohpsk.Nsymbrowpilot*M+1:2*acohpsk.Nsymbrowpilot*M) = ch_fdm_frame;
-
- next_sync = sync;
- sync = 0;
- if sync == 0
- acohpsk.f_est = Fcentre;
- end
-
- [rx_fdm_frame_bb afdmdv.fbb_phase_rx] = freq_shift(ch_fdm_frame_buf, -acohpsk.f_est, Fs, afdmdv.fbb_phase_rx);
- [ch_symb rx_timing rx_filt rx_baseband afdmdv] = rate_Fs_rx_processing(afdmdv, rx_fdm_frame_bb, 2*acohpsk.Nsymbrowpilot, nin);
- ch_symb_log = [ch_symb_log; ch_symb(acohpsk.Nsymbrowpilot+1:2*acohpsk.Nsymbrowpilot,:)];
-
- % coarse timing (frame sync) and initial fine freq est ---------------------------------------------
-
- acohpsk.ct_symb_buf = update_ct_symb_buf(acohpsk.ct_symb_buf, ch_symb, acohpsk.Nct_sym_buf, acohpsk.Nsymbrowpilot);
- [next_sync acohpsk] = frame_sync_fine_freq_est(acohpsk, ch_symb(acohpsk.Nsymbrowpilot+1:2*acohpsk.Nsymbrowpilot,:), sync, next_sync);
-
- % we've found a sync candidate
-
- if (next_sync == 1)
-
- % rewind and re-process last few frames with f_est
-
- acohpsk.f_est -= acohpsk.f_fine_est;
- printf(" [%d] trying sync and f_est: %f\n", f, acohpsk.f_est);
- [rx_fdm_frame_bb afdmdv.fbb_phase_rx] = freq_shift(ch_fdm_frame_buf, -acohpsk.f_est, Fs, afdmdv.fbb_phase_rx);
- [ch_symb rx_timing rx_filt rx_baseband afdmdv] = rate_Fs_rx_processing(afdmdv, rx_fdm_frame_bb, 2*acohpsk.Nsymbrowpilot, nin);
- acohpsk.ct_symb_buf = update_ct_symb_buf(acohpsk.ct_symb_buf, ch_symb, acohpsk.Nct_sym_buf, acohpsk.Nsymbrowpilot);
- [next_sync acohpsk] = frame_sync_fine_freq_est(acohpsk, ch_symb(acohpsk.Nsymbrowpilot+1:2*acohpsk.Nsymbrowpilot,:), sync, next_sync);
-
- % candidate checks out so log stats
-
- if (next_sync == 1)
- printf(" [%d] in sync!\n", f);
- freq_offset_log = [freq_offset_log Fcentre+foff-acohpsk.f_est];
- sync_time_log = [sync_time_log f-sync_start];
- next_sync = 0; sync_start = f;
- end
- end
-
- %printf("f: %d sync: %d next_sync: %d\n", f, sync, next_sync);
- [sync acohpsk] = sync_state_machine(acohpsk, sync, next_sync);
-
- end
-
- % ftx=fopen("coarse_tx.raw","wb"); fwrite(ftx, 1000*ch_fdm_frame_log, "short"); fclose(ftx);
-
- sim_out.freq_offset_log = freq_offset_log;
- sim_out.sync_time_log = sync_time_log;
- sim_out.ch_fdm_frame_log = ch_fdm_frame_log;
- sim_out.ch_symb_log = ch_symb_log;
- sim_out.tx_fdm_frame_log = tx_fdm_frame_log;
-endfunction
-
-
-function freq_off_est_test_single
- sim_in.frames = 10;
- sim_in.EsNodB = 100;
- sim_in.foff = 10;
- sim_in.dfoff = 0;
- sim_in.fading_en = 0;
-
- sim_out = freq_off_est_test(sim_in);
-
- figure(1)
- subplot(211)
- plot(sim_out.freq_offset_log)
- subplot(212)
- hist(sim_out.freq_offset_log)
-
- figure(2)
- subplot(211)
- plot(sim_out.sync_time_log)
- subplot(212)
- hist(sim_out.sync_time_log)
-
- figure(3)
- subplot(211)
- plot(real(sim_out.tx_fdm_frame_log(1:2*960)))
- subplot(212)
- plot(real(sim_out.ch_symb_log),'+')
-endfunction
-
-
-function [freq_off_log EsNodBSet] = freq_off_est_test_curves
- EsNodBSet = [20 12 8];
-
- sim_in.frames = 100;
- sim_in.foff = -20;
- sim_in.dfoff = 0;
- sim_in.fading_en = 1;
- freq_off_log = 1E6*ones(sim_in.frames, length(EsNodBSet) );
- sync_time_log = 1E6*ones(sim_in.frames, length(EsNodBSet) );
-
- for i=1:length(EsNodBSet)
- sim_in.EsNodB = EsNodBSet(i);
- printf("%f\n", sim_in.EsNodB);
-
- sim_out = freq_off_est_test(sim_in);
- freq_off_log(1:length(sim_out.freq_offset_log),i) = sim_out.freq_offset_log;
- sync_time_log(1:length(sim_out.sync_time_log),i) = sim_out.sync_time_log;
- end
-
- figure(1)
- clf
- hold on;
- for i=1:length(EsNodBSet)
- data = freq_off_log(find(freq_off_log(:,i) < 1E6),i);
- s = std(data);
- m = mean(data);
- stdbar = [m-s; m+s];
- plot(EsNodBSet(i), data, '+')
- plot([EsNodBSet(i) EsNodBSet(i)]+0.5, stdbar,'+-')
- end
- hold off
-
- axis([6 22 -25 25])
- if sim_in.fading_en
- title_str = sprintf('foff = %d Hz Fading', sim_in.foff);
- else
- title_str = sprintf('foff = %d Hz AWGN', sim_in.foff);
- end
- title(title_str);
- xlabel('Es/No (dB)')
- ylabel('freq offset error (Hz)');
-
- figure(2)
- clf
- hold on;
- for i=1:length(EsNodBSet)
- leg = sprintf("%d;%d dB;", i, EsNodBSet(i));
- plot(freq_off_log(find(freq_off_log(:,i) < 1E6),i),leg)
- end
- hold off;
- title(title_str);
- xlabel('test');
- ylabel('freq offset error (Hz)');
- legend('boxoff');
-
- figure(3)
- clf
- hold on;
- for i=1:length(EsNodBSet)
- data = sync_time_log(find(sync_time_log(:,i) < 1E6),i);
- if length(data)
- s = std(data);
- m = mean(data);
- stdbar = [m-s; m+s];
- plot(EsNodBSet(i), data, '+')
- plot([EsNodBSet(i) EsNodBSet(i)]+0.5, stdbar,'+-')
- end
- end
- hold off;
- axis([6 22 0 10])
- ylabel('sync time (frames)')
- xlabel('Es/No (dB)');
- title(title_str);
-
- figure(4)
- clf
- hold on;
- for i=1:length(EsNodBSet)
- leg = sprintf("%d;%d dB;", i, EsNodBSet(i));
- plot(sync_time_log(find(sync_time_log(:,i) < 1E6),i),leg)
- end
- hold off;
- title(title_str);
- xlabel('test');
- ylabel('sync time (frames)');
- legend('boxoff');
-
-endfunction
-
-
-freq_off_est_test_single;
-%freq_off_est_test_curves;
-
-% 1. start with +/- 20Hz offset
-% 2. Measure frames to sync. How to define sync? Foff to withn 1 Hz. Sync state
-% Need to see if we get false sync
-% 3. Try shortened filter
-% 4. Extend to parallel demods at +/-
+% test_foff.m\r
+% David Rowe April 2015\r
+%\r
+% Octave script for testing the cohpsk freq offset estimator\r
+\r
+graphics_toolkit ("gnuplot");\r
+more off;\r
+\r
+cohpsk;\r
+fdmdv;\r
+autotest;\r
+\r
+rand('state',1); \r
+randn('state',1);\r
+\r
+ \r
+% Core function for testing frequency offset estimator. Performs one test\r
+\r
+function sim_out = freq_off_est_test(sim_in)\r
+ global Nfilter;\r
+ global M;\r
+\r
+ Rs = 50;\r
+ Nc = 4;\r
+ Nd = 2;\r
+ framesize = 32;\r
+ Fs = 8000;\r
+ Fcentre = 1500;\r
+ \r
+ Nsw = 3; % numbers of sync window frames we process over. Set based\r
+ % on Nsym to flush filter memory by final frame in windw\r
+\r
+ afdmdv.Nsym = 5;\r
+ afdmdv.Nt = 5;\r
+\r
+ afdmdv.Fs = 8000;\r
+ afdmdv.Nc = Nd*Nc-1;\r
+ afdmdv.Rs = Rs;\r
+ afdmdv.M = afdmdv.Fs/afdmdv.Rs;\r
+ afdmdv.tx_filter_memory = zeros(afdmdv.Nc+1, Nfilter);\r
+ afdmdv.Nfilter = Nfilter;\r
+ afdmdv.gt_alpha5_root = gen_rn_coeffs(0.5, 1/Fs, Rs, afdmdv.Nsym, afdmdv.M);\r
+ afdmdv.Fsep = 75;\r
+ afdmdv.phase_tx = ones(afdmdv.Nc+1,1);\r
+ freq_hz = afdmdv.Fsep*( -Nc*Nd/2 - 0.5 + (1:Nc*Nd) );\r
+ afdmdv.freq_pol = 2*pi*freq_hz/Fs;\r
+ afdmdv.freq = exp(j*afdmdv.freq_pol);\r
+ afdmdv.Fcentre = 1500;\r
+\r
+ afdmdv.fbb_rect = exp(j*2*pi*Fcentre/Fs);\r
+ afdmdv.fbb_phase_tx = 1;\r
+ afdmdv.fbb_phase_rx = 1;\r
+ afdmdv.phase_rx = ones(afdmdv.Nc+1,1);\r
+\r
+ nin = M;\r
+\r
+ P = afdmdv.P = 4;\r
+ afdmdv.Nfilter = afdmdv.Nsym*afdmdv.M;\r
+ afdmdv.rx_filter_mem_timing = zeros(afdmdv.Nc+1, afdmdv.Nt*afdmdv.P);\r
+ afdmdv.Nfiltertiming = afdmdv.M + afdmdv.Nfilter + afdmdv.M;\r
+ afdmdv.rx_filter_memory = zeros(afdmdv.Nc+1, afdmdv.Nfilter);\r
+\r
+ acohpsk = standard_init();\r
+ acohpsk.framesize = framesize;\r
+ acohpsk.ldpc_code = 0;\r
+ acohpsk.ldpc_code_rate = 1;\r
+ acohpsk.Nc = Nc;\r
+ acohpsk.Rs = Rs;\r
+ acohpsk.Ns = 4;\r
+ acohpsk.Nd = Nd;\r
+ acohpsk.modulation = 'qpsk';\r
+ acohpsk.do_write_pilot_file = 0;\r
+ acohpsk = symbol_rate_init(acohpsk);\r
+ acohpsk.Ncm = 10*acohpsk.Nsymbrowpilot*M;\r
+ acohpsk.coarse_mem = zeros(1,acohpsk.Ncm);\r
+ acohpsk.Ndft = 2^(ceil(log2(acohpsk.Ncm)));\r
+ \r
+ ch_fdm_frame_buf = zeros(1, Nsw*acohpsk.Nsymbrowpilot*M);\r
+\r
+ frames = sim_in.frames;\r
+ EsNodB = sim_in.EsNodB;\r
+ foff = sim_in.foff;\r
+ dfoff = sim_in.dfoff;\r
+ fading_en = sim_in.fading_en;\r
+\r
+ EsNo = 10^(EsNodB/10);\r
+ hf_delay_ms = 2;\r
+ phase_ch = 1;\r
+\r
+ rand('state',1); \r
+ tx_bits_coh = round(rand(1,framesize*10));\r
+ ptx_bits_coh = 1;\r
+ [spread spread_2ms hf_gain] = init_hf_model(Fs, Fs, frames*acohpsk.Nsymbrowpilot*afdmdv.M);\r
+\r
+ hf_n = 1;\r
+ nhfdelay = floor(hf_delay_ms*Fs/1000);\r
+ ch_fdm_delay = zeros(1, acohpsk.Nsymbrowpilot*M + nhfdelay);\r
+ \r
+ sync = 0; next_sync = 1;\r
+ sync_start = 1;\r
+ freq_offset_log = [];\r
+ sync_time_log = [];\r
+ ch_fdm_frame_log = [];\r
+ ch_symb_log = [];\r
+ tx_fdm_frame_log = [];\r
+\r
+ for f=1:frames\r
+\r
+ acohpsk.frame = f;\r
+\r
+ %\r
+ % Mod --------------------------------------------------------------------\r
+ %\r
+\r
+ tx_bits = tx_bits_coh(ptx_bits_coh:ptx_bits_coh+framesize-1);\r
+ ptx_bits_coh += framesize;\r
+ if ptx_bits_coh > length(tx_bits_coh)\r
+ ptx_bits_coh = 1;\r
+ end \r
+\r
+ [tx_symb tx_bits] = bits_to_qpsk_symbols(acohpsk, tx_bits, [], []);\r
+\r
+ tx_fdm_frame = [];\r
+ for r=1:acohpsk.Nsymbrowpilot\r
+ tx_onesymb = tx_symb(r,:);\r
+ [tx_baseband afdmdv] = tx_filter(afdmdv, tx_onesymb);\r
+ [tx_fdm afdmdv] = fdm_upconvert(afdmdv, tx_baseband);\r
+ tx_fdm_frame = [tx_fdm_frame tx_fdm];\r
+ end\r
+ tx_fdm_frame_log = [tx_fdm_frame_log tx_fdm_frame];\r
+\r
+ %\r
+ % Channel --------------------------------------------------------------------\r
+ %\r
+\r
+ ch_fdm_frame = zeros(1,acohpsk.Nsymbrowpilot*M);\r
+ for i=1:acohpsk.Nsymbrowpilot*M\r
+ foff_rect = exp(j*2*pi*foff/Fs);\r
+ foff += dfoff;\r
+ phase_ch *= foff_rect;\r
+ ch_fdm_frame(i) = tx_fdm_frame(i) * phase_ch;\r
+ end\r
+ phase_ch /= abs(phase_ch);\r
+\r
+ if fading_en\r
+ ch_fdm_delay(1:nhfdelay) = ch_fdm_delay(acohpsk.Nsymbrowpilot*M+1:nhfdelay+acohpsk.Nsymbrowpilot*M);\r
+ ch_fdm_delay(nhfdelay+1:nhfdelay+acohpsk.Nsymbrowpilot*M) = ch_fdm_frame;\r
+\r
+ for i=1:acohpsk.Nsymbrowpilot*M\r
+ ahf_model = hf_gain*(spread(hf_n)*ch_fdm_frame(i) + spread_2ms(hf_n)*ch_fdm_delay(i));\r
+ ch_fdm_frame(i) = ahf_model;\r
+ hf_n++;\r
+ end\r
+ end\r
+\r
+ % each carrier has power = 2, total power 2Nc, total symbol rate NcRs, noise BW B=Fs\r
+ % Es/No = (C/Rs)/(N/B), N = var = 2NcFs/NcRs(Es/No) = 2Fs/Rs(Es/No)\r
+\r
+ variance = 2*Fs/(acohpsk.Rs*EsNo);\r
+ uvnoise = sqrt(0.5)*(randn(1,acohpsk.Nsymbrowpilot*M) + j*randn(1,acohpsk.Nsymbrowpilot*M));\r
+ noise = sqrt(variance)*uvnoise;\r
+\r
+ ch_fdm_frame += noise;\r
+ ch_fdm_frame_log = [ch_fdm_frame_log ch_fdm_frame];\r
+\r
+ %\r
+ % Try to achieve sync --------------------------------------------------------------------\r
+ %\r
+\r
+ % store Nsw frames so we can rewind if we get a good candidate\r
+\r
+ ch_fdm_frame_buf(1:(Nsw-1)*acohpsk.Nsymbrowpilot*M) = ch_fdm_frame_buf(acohpsk.Nsymbrowpilot*M+1:Nsw*acohpsk.Nsymbrowpilot*M);\r
+ ch_fdm_frame_buf((Nsw-1)*acohpsk.Nsymbrowpilot*M+1:Nsw*acohpsk.Nsymbrowpilot*M) = ch_fdm_frame;\r
+\r
+ next_sync = sync;\r
+ sync = 0;\r
+ if sync == 0\r
+ acohpsk.f_est = Fcentre;\r
+ end\r
+\r
+ [rx_fdm_frame_bb afdmdv.fbb_phase_rx] = freq_shift(ch_fdm_frame_buf, -acohpsk.f_est, Fs, afdmdv.fbb_phase_rx);\r
+ [ch_symb rx_timing rx_filt rx_baseband afdmdv] = rate_Fs_rx_processing(afdmdv, rx_fdm_frame_bb, Nsw*acohpsk.Nsymbrowpilot, nin);\r
+ ch_symb_log = [ch_symb_log; ch_symb((Nsw-1)*acohpsk.Nsymbrowpilot+1:Nsw*acohpsk.Nsymbrowpilot,:)];\r
+\r
+ % coarse timing (frame sync) and initial fine freq est ---------------------------------------------\r
+ \r
+ for i=1:Nsw-1\r
+ acohpsk.ct_symb_buf = update_ct_symb_buf(acohpsk.ct_symb_buf, ch_symb((i-1)*acohpsk.Nsymbrowpilot+1:i*acohpsk.Nsymbrowpilot,:), acohpsk.Nct_sym_buf, acohpsk.Nsymbrowpilot);\r
+ end\r
+ [next_sync acohpsk] = frame_sync_fine_freq_est(acohpsk, ch_symb((Nsw-1)*acohpsk.Nsymbrowpilot+1:Nsw*acohpsk.Nsymbrowpilot,:), sync, next_sync);\r
+\r
+ % we've found a sync candidate\r
+\r
+ if (next_sync == 1)\r
+\r
+ % rewind and re-process last few frames with f_est\r
+\r
+ acohpsk.f_est -= acohpsk.f_fine_est;\r
+ printf(" [%d] trying sync and f_est: %f\n", f, acohpsk.f_est);\r
+ [rx_fdm_frame_bb afdmdv.fbb_phase_rx] = freq_shift(ch_fdm_frame_buf, -acohpsk.f_est, Fs, afdmdv.fbb_phase_rx);\r
+ [ch_symb rx_timing rx_filt rx_baseband afdmdv] = rate_Fs_rx_processing(afdmdv, rx_fdm_frame_bb, Nsw*acohpsk.Nsymbrowpilot, nin);\r
+ for i=1:Nsw-1\r
+ acohpsk.ct_symb_buf = update_ct_symb_buf(acohpsk.ct_symb_buf, ch_symb((i-1)*acohpsk.Nsymbrowpilot+1:i*acohpsk.Nsymbrowpilot,:), acohpsk.Nct_sym_buf, acohpsk.Nsymbrowpilot);\r
+ end\r
+ [next_sync acohpsk] = frame_sync_fine_freq_est(acohpsk, ch_symb((Nsw-1)*acohpsk.Nsymbrowpilot+1:Nsw*acohpsk.Nsymbrowpilot,:), sync, next_sync);\r
+ if abs(acohpsk.f_fine_est) > 2\r
+ printf(" [%d] Hmm %f is a bit big so back to coarse est ...\n", f, acohpsk.f_fine_est);\r
+ next_sync = 0;\r
+ end\r
+\r
+ % candidate checks out so log stats\r
+\r
+ if (next_sync == 1)\r
+ printf(" [%d] in sync!\n", f);\r
+ freq_offset_log = [freq_offset_log Fcentre+foff-acohpsk.f_est];\r
+ sync_time_log = [sync_time_log f-sync_start];\r
+ next_sync = 0; sync_start = f;\r
+ end\r
+ end\r
+\r
+ %printf("f: %d sync: %d next_sync: %d\n", f, sync, next_sync);\r
+ [sync acohpsk] = sync_state_machine(acohpsk, sync, next_sync);\r
+\r
+ end\r
+\r
+ % ftx=fopen("coarse_tx.raw","wb"); fwrite(ftx, 1000*ch_fdm_frame_log, "short"); fclose(ftx);\r
+\r
+ sim_out.freq_offset_log = freq_offset_log;\r
+ sim_out.sync_time_log = sync_time_log;\r
+ sim_out.ch_fdm_frame_log = ch_fdm_frame_log;\r
+ sim_out.ch_symb_log = ch_symb_log;\r
+ sim_out.tx_fdm_frame_log = tx_fdm_frame_log;\r
+endfunction\r
+\r
+\r
+function freq_off_est_test_single\r
+ sim_in.frames = 100;\r
+ sim_in.EsNodB = 12;\r
+ sim_in.foff = -20;\r
+ sim_in.dfoff = 0;\r
+ sim_in.fading_en = 1;\r
+\r
+ sim_out = freq_off_est_test(sim_in);\r
+\r
+ figure(1)\r
+ subplot(211)\r
+ plot(sim_out.freq_offset_log)\r
+ subplot(212)\r
+ hist(sim_out.freq_offset_log)\r
+\r
+ figure(2)\r
+ subplot(211)\r
+ plot(sim_out.sync_time_log)\r
+ subplot(212)\r
+ hist(sim_out.sync_time_log)\r
+\r
+ figure(3)\r
+ subplot(211)\r
+ plot(real(sim_out.tx_fdm_frame_log(1:2*960)))\r
+ grid;\r
+ subplot(212)\r
+ plot(real(sim_out.ch_symb_log),'+')\r
+ grid;\r
+endfunction\r
+\r
+\r
+function [freq_off_log EsNodBSet] = freq_off_est_test_curves\r
+ EsNodBSet = [20 12 8];\r
+\r
+ sim_in.frames = 100;\r
+ sim_in.foff = -20;\r
+ sim_in.dfoff = 0;\r
+ sim_in.fading_en = 1;\r
+ freq_off_log = 1E6*ones(sim_in.frames, length(EsNodBSet) );\r
+ sync_time_log = 1E6*ones(sim_in.frames, length(EsNodBSet) );\r
+\r
+ for i=1:length(EsNodBSet)\r
+ sim_in.EsNodB = EsNodBSet(i);\r
+ printf("%f\n", sim_in.EsNodB);\r
+\r
+ sim_out = freq_off_est_test(sim_in);\r
+ freq_off_log(1:length(sim_out.freq_offset_log),i) = sim_out.freq_offset_log;\r
+ sync_time_log(1:length(sim_out.sync_time_log),i) = sim_out.sync_time_log;\r
+ end\r
+\r
+ figure(1)\r
+ clf\r
+ hold on;\r
+ for i=1:length(EsNodBSet)\r
+ data = freq_off_log(find(freq_off_log(:,i) < 1E6),i);\r
+ s = std(data);\r
+ m = mean(data);\r
+ stdbar = [m-s; m+s];\r
+ plot(EsNodBSet(i), data, '+')\r
+ plot([EsNodBSet(i) EsNodBSet(i)]+0.5, stdbar,'+-')\r
+ end\r
+ hold off\r
+\r
+ axis([6 22 -25 25])\r
+ if sim_in.fading_en\r
+ title_str = sprintf('foff = %d Hz Fading', sim_in.foff);\r
+ else\r
+ title_str = sprintf('foff = %d Hz AWGN', sim_in.foff);\r
+ end\r
+ title(title_str);\r
+ xlabel('Es/No (dB)')\r
+ ylabel('freq offset error (Hz)');\r
+ \r
+ figure(2)\r
+ clf\r
+ hold on;\r
+ for i=1:length(EsNodBSet)\r
+ leg = sprintf("%d;%d dB;", i, EsNodBSet(i));\r
+ plot(freq_off_log(find(freq_off_log(:,i) < 1E6),i),leg)\r
+ end\r
+ hold off;\r
+ title(title_str);\r
+ xlabel('test');\r
+ ylabel('freq offset error (Hz)');\r
+ legend('boxoff');\r
+\r
+ figure(3)\r
+ clf\r
+ hold on;\r
+ for i=1:length(EsNodBSet)\r
+ data = sync_time_log(find(sync_time_log(:,i) < 1E6),i);\r
+ if length(data) \r
+ s = std(data);\r
+ m = mean(data);\r
+ stdbar = [m-s; m+s];\r
+ plot(EsNodBSet(i), data, '+')\r
+ plot([EsNodBSet(i) EsNodBSet(i)]+0.5, stdbar,'+-')\r
+ end\r
+ end \r
+ hold off;\r
+ axis([6 22 0 10])\r
+ ylabel('sync time (frames)')\r
+ xlabel('Es/No (dB)');\r
+ title(title_str);\r
+\r
+ figure(4)\r
+ clf\r
+ hold on;\r
+ for i=1:length(EsNodBSet)\r
+ leg = sprintf("%d;%d dB;", i, EsNodBSet(i));\r
+ plot(sync_time_log(find(sync_time_log(:,i) < 1E6),i),leg)\r
+ end\r
+ hold off;\r
+ title(title_str);\r
+ xlabel('test');\r
+ ylabel('sync time (frames)');\r
+ legend('boxoff');\r
+\r
+endfunction\r
+\r
+\r
+%freq_off_est_test_single;\r
+freq_off_est_test_curves;\r
+\r
+% 1. start with +/- 20Hz offset\r
+% 2. Measure frames to sync. How to define sync? Foff to withn 1 Hz. Sync state\r
+% Need to see if we get false sync\r
+% 3. Try shortened filter\r
+% 4. Extend to parallel demods at +/- \r
projects / freetel-svn-tracking.git / commitdiff