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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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76
test/duobinary_emulation_minimal_example.m
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@@ -1,65 +1,49 @@
useprbs = 1;
M = 6;
randkey = 1;
datarate = 224e9;
fsym = round(datarate / log2(M)) ;
apply_precode = 1;
db_pre = 1;
bitpattern = [];
s = RandStream('twister','Seed',1);
for i = 1:log2(M)
N = 2^(17-1); %length of prbs
bitpattern(:,i) = randi(s,[0 1], N, 1);
end
Pform = Pulseformer("fsym",fsym,"fdac",4*fsym,"pulse","rrc","pulselength",16,"rrcalpha",0.05);
if M == 6
bitpattern = reshape(bitpattern',[],1);
bitpattern = bitpattern(1:end-mod(length(bitpattern),5));
end
[d,Symbols,Bits] = PAMsource(...
"fsym",fsym,"M",M,"order",17,"useprbs",1,...
"fs_out",fsym,...
"applyclipping",0,"clipfactor",1.5,...
"applypulseform",0,"pulseformer",Pform,...
"randkey",1,...
"db_precode",db_pre,"db_encode",0,...
"mrds_code",0,"mrds_blocklength",512).process();
bits = Informationsignal(bitpattern);
%%%CHANNEL
symbols = PAMmapper(M,0).map(bits);
% s = RandStream('twister','Seed',2);
% start = 10000;
% burstwidth = 100;
% d_burst = d;
% for pos = start:start+burstwidth
% lvls = 1.5 .* PAMmapper(M,0).levels / rms(PAMmapper(M,0).levels);
% d_burst.signal(pos) = d.signal(pos)+randn(s,1,1);
% end
bits_rx = PAMmapper(M,0).demap(symbols);
[~,~,ber_direct,~] = calc_ber(bits.signal,bits_rx.signal,"skip_front",0,"skip_end",0,"returnErrorLocation",1);
d_resample = d.resample("fs_out",2.*fsym);
if apply_precode
symbols_tx = Duobinary().precode(symbols);
else
symbols_tx = symbols;
end
eq_ffe = FFE("epochs_tr",5,"epochs_dd",5,"len_tr",1024,"mu_dd",0.0004,"mu_tr",0,"order",25,"sps",2,"decide",1);
d_eq = eq_ffe.process(d_resample,Symbols);
show2Dconstellation(symbols_tx,symbols_tx,"displayname",'VNLE Out','fignum',2241);
% s = RandStream('twister','Seed',2);
% start = 10000;
% burstwidth = 100;
% d_burst = d_eq;
% for pos = start:start+burstwidth
% lvls = 1.5 .* PAMmapper(M,0).levels / rms(PAMmapper(M,0).levels);
% d_burst.signal(pos) = d_eq.signal(pos)+randn(s,1,1);
% end
%
% d_burst = PAMmapper(M,0).decide_pamlevel(d_burst);
if db_pre
if apply_precode
% Entschiedene Symbole codieren: d_DB(n) = d(n) + d(n-1) (im Fall von PAM4 7 level [0 1 2 3 4 5 6])
d_db = Duobinary().encode(d);
symbols_db = Duobinary().encode(symbols_tx);
% Entschiedene codierte Symbole decodieren: d_dec(n) = d_DB(n) mod4
d_dec = Duobinary().decode(d_db);
symbols_rx = Duobinary().decode(symbols_db);
else
d_dec = d_burst;
symbols_rx = symbols_tx;
end
% Vergleichen von b(n) und d_dec(n)
Rx_bits = PAMmapper(M,0).demap(d_dec);
Tx_bits = Bits;
[~,error_num,ber,error_pos] = calc_ber(Tx_bits.signal,Rx_bits.signal,"skip_front",0,"skip_end",0,"returnErrorLocation",1);
bits_rx = PAMmapper(M,0).demap(symbols_rx);
[~,~,ber,~] = calc_ber(bits.signal,bits_rx.signal,"skip_front",10,"skip_end",10,"returnErrorLocation",1);
disp(['BER: ',sprintf('%.1E',ber),' - - PAM-',num2str(M)]);