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BCJR implementation

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WDM code added (Pol Cont., Opt MUX/DEMUX, Opt Atten, DP_Fiber) -> the codebase is not optimized to always work with dp signals!
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Silas Oettinghaus
2025-09-17 13:58:58 +02:00
parent f4a22d23a2
commit 4099f6820f
37 changed files with 3643 additions and 593 deletions
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40
Functions/EQ_structures/duobinary_target.m
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@@ -23,8 +23,14 @@ if ~isempty(options.postFFE)
end
mlse_.DIR = [1,1];
% mlse_sig_sd = mlse_.process(eq_signal);
[mlse_sig_sd,LLR,GMI_MLSE] = mlse_.process(eq_signal,tx_symbols);
%
if isa(mlse_,'MLSE_viterbi')
mlse_sig_sd = mlse_.process(eq_signal);
else
[mlse_sig_sd,LLR,GMI_MLSE] = mlse_.process(eq_signal,tx_symbols);
end
mlse_sig_hd = PAMmapper(M,0,"eth_style",options.eth_style_symbol_mapping).quantize(mlse_sig_sd);
% precoding to mitigate error propagation, most prominently used in
@@ -43,8 +49,8 @@ switch options.precode_mode
tx_symbols_precoded = Duobinary().decode(tx_symbols_precoded);
tx_bits_precoded = PAMmapper(M,0,"eth_style",options.eth_style_symbol_mapping).demap(tx_symbols_precoded);
rx_bits_mlse = PAMmapper(M,0,"eth_style",options.eth_style_symbol_mapping).demap(mlse_sig_hd_precoded);
[~,errors_db_diff_precoded,ber_db_diff_precoded,~] = calc_ber(rx_bits_mlse.signal,tx_bits_precoded.signal,"skip_front",100,"skip_end",150,"returnErrorLocation",1);
%B) Just determine BER
@@ -59,24 +65,42 @@ switch options.precode_mode
mlse_sig_hd_decoded = Duobinary().encode(mlse_sig_hd,"M",M);
mlse_sig_hd_decoded = Duobinary().decode(mlse_sig_hd_decoded,"M",M);
rx_bits_mlse_decoded = PAMmapper(M,0,"eth_style",options.eth_style_symbol_mapping).demap(mlse_sig_hd_decoded);
[~,errors_db_diff_precoded,ber_db_diff_precoded,~] = calc_ber(rx_bits_mlse_decoded.signal,tx_bits.signal,"skip_front",100,"skip_end",150,"returnErrorLocation",1);
[~,errors_db_diff_precoded,ber_db_diff_precoded,a] = calc_ber(rx_bits_mlse_decoded.signal,tx_bits.signal,"skip_front",100,"skip_end",150,"returnErrorLocation",1);
burst_db_precoded = count_error_bursts(a, 40);
% B) Omit the Coding by comparing with demapped TX symbol sequence
tx_bits = PAMmapper(M,0,"eth_style",options.eth_style_symbol_mapping).demap(tx_symbols);
rx_bits_mlse = PAMmapper(M,0,"eth_style",options.eth_style_symbol_mapping).demap(mlse_sig_hd);
[bits_db,errors_db,ber_db,~] = calc_ber(rx_bits_mlse.signal,tx_bits.signal,"skip_front",100,"skip_end",150,"returnErrorLocation",1);
[bits_db,errors_db,ber_db,a] = calc_ber(rx_bits_mlse.signal,tx_bits.signal,"skip_front",100,"skip_end",150,"returnErrorLocation",1);
burst_db = count_error_bursts(a, 40);
cols = linspecer(8);
figure();hold on;
stem(1:40,burst_db,'LineWidth',1,'Color',cols(4,:),'Marker','_','DisplayName','w/o diff. precoder');
stem(1:40,burst_db_precoded,'LineWidth',1,'Color',cols(3,:),'Marker','.','LineStyle','-','DisplayName','w diff. precoder');
xlabel('Bit Error Burst Length')
ylabel('Occurence')
set(gca, 'yscale', 'log');
end
% M = numel(unique(tx_symbols.signal));
rx_bits = PAMmapper(M,0,"eth_style",options.eth_style_symbol_mapping).demap(mlse_sig_hd);
[bits_db,errors_db,ber_db,errorIndice_db] = calc_ber(rx_bits.signal,tx_bits.signal,"skip_front",100,"skip_end",150,"returnErrorLocation",1);
alpha = arburg(eq_noise.signal,1);%pf_.coefficients(2);
alpha = alpha(2);
gmi_mlse = GMI_MLSE;
air_mlse = tx_symbols.fs .* floor(log2(double(M))*10)/10 .* gmi_mlse ./ log2(double(M));
if isa(mlse_,'MLSE_viterbi')
gmi_mlse = NaN;
air_mlse = NaN;
else
gmi_mlse = GMI_MLSE;
air_mlse = tx_symbols.fs .* floor(log2(double(M))*10)/10 .* gmi_mlse ./ log2(double(M));
end
db_results = struct();
db_results.metrics = Metricstruct;