76 lines
2.7 KiB
Matlab
76 lines
2.7 KiB
Matlab
% einstellungen
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M = 4;
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apply_precode_at_tx = 0;
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emulate_precode = 1;
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% daten erzeugen
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bitpattern = [];
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s = RandStream('twister','Seed',1);
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for i = 1:log2(M)
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N = 2^(17-1); %length of prbs
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bitpattern(:,i) = randi(s,[0 1], N, 1);
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end
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if M == 6
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bitpattern = reshape(bitpattern',[],1);
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bitpattern = bitpattern(1:end-mod(length(bitpattern),5));
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end
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tx_bits = Informationsignal(bitpattern);
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tx_symbols = PAMmapper(M,0).map(tx_bits);
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if apply_precode_at_tx
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tx_symbols = Duobinary().precode(tx_symbols);
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if emulate_precode
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% ansatz 1B) Omit precode (einfach precoded empfangen, nichts weiter machen und normal prozessieren - möglich weil konstellation sich nicht ändert)
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rx_symbols = tx_symbols;
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bits_rx = PAMmapper(M,0).demap(rx_symbols);
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% beachten, dass man die tx_bits anpassen muss, da man ja mit precoded symbolen vergleicht
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tx_bits = PAMmapper(M,0).demap(tx_symbols);
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else
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% ansatz 1A) Precode normal:
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% Entschiedene Symbole codieren: d_DB(n) = d(n) + d(n-1) (im Fall von PAM4 7 level [0 1 2 3 4 5 6])
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symbols_db = Duobinary().encode(tx_symbols);
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% Entschiedene codierte Symbole decodieren: d_dec(n) = d_DB(n) mod4
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rx_symbols = Duobinary().decode(symbols_db);
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bits_rx = PAMmapper(M,0).demap(rx_symbols);
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end
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[~,~,ber,~] = calc_ber(tx_bits.signal,bits_rx.signal,"skip_front",0,"skip_end",0,"returnErrorLocation",1);
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disp(['BER: ',sprintf('%.1E',ber)]);
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assert(ber == 0)
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else
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if emulate_precode
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% emulate precode:
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% Entschiedene Symbole codieren: d_DB(n) = d(n) + d(n-1) (im Fall von PAM4 7 level [0 1 2 3 4 5 6])
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symbols_db = Duobinary().encode(tx_symbols); % das wäre der FFE mit db target
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% Entschiedene codierte Symbole decodieren: d_dec(n) = d_DB(n) mod4
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rx_symbols = Duobinary().decode(symbols_db); % modulo
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bits_rx = PAMmapper(M,0).demap(rx_symbols); % demappen
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% ref symbole precoden, auch hier muss man wieder etwas fummeln wegen der emulation:
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% encode + decode == remove precoding (mathematisch die gleiche operation)
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tx_symbols_ref = Duobinary().encode(tx_symbols);
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tx_symbols_ref = Duobinary().decode(tx_symbols_ref);
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tx_bits = PAMmapper(M,0).demap(tx_symbols_ref);
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else
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% normal detection without any precode stuff
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symbols_db = Duobinary().encode(tx_symbols);
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rx_symbols = tx_symbols;
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bits_rx = PAMmapper(M,0).demap(rx_symbols);
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end
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[~,~,ber,~] = calc_ber(tx_bits.signal,bits_rx.signal,"skip_front",1,"skip_end",1,"returnErrorLocation",1);
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disp(['BER: ',sprintf('%.1E',ber)]);
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assert(ber == 0)
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end
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