102 lines
3.5 KiB
Matlab
102 lines
3.5 KiB
Matlab
function [eq_package] = vnle(eq_,M,rx_signal,tx_symbols,tx_bits,options)
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%VNLE Apply an equalization algorithm to the received signal and calculate BER
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% This function takes an equalizer object, a received signal, and the
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% transmitted symbols to apply equalization, map the received signal back to bits,
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% and compute the bit error rate (BER).
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%
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% Inputs:
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% EQ - Equalizer object that provides the equalization method
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% rx_signal - Received signal that needs to be equalized
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% tx_symbols - Transmitted symbols used as a reference for BER calculation
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%
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% Outputs:
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% eq_signal - Equalized version of the received signal
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% ber - Bit error rate after equalization
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% numErrors - Number of bit errors detected
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arguments
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eq_
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M
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rx_signal
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tx_symbols
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tx_bits
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options.precode_mode db_mode
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options.showAnalysis = 0
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options.eth_style = 0;
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end
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%FFE or VNLE
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if length(rx_signal)/2 == length(tx_symbols)+0.5
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rx_signal.signal = rx_signal.signal(1:end-1);
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elseif length(rx_signal)/2 == length(tx_symbols)-1
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end
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[eq_signal_sd,eq_noise] = eq_.process(rx_signal,tx_symbols);
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eq_signal_hd = PAMmapper(M,0).quantize(eq_signal_sd);
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% precoding to mitigate error propagation, most prominently used in
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% combination with duobinary signaling to avoid catastrophic error
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% behavior (see J.W.M. Bergmans, Digital Baseband Transmission and Recording -> partial response signaling)
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% takes:
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% -> eq_signal_hd: hard decision signal after eq
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% -> tx_symbols: that where used as reference for eq
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switch options.precode_mode
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case db_mode.db_emulate
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% re
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eq_signal_hd = Duobinary().encode(eq_signal_hd,"M",M);
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eq_signal_hd = Duobinary().decode(eq_signal_hd,"M",M);
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tx_symbols_precoded = Duobinary().encode(tx_symbols);
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tx_symbols_precoded = Duobinary().decode(tx_symbols_precoded);
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tx_bits = PAMmapper(M,0,"eth_style",options.eth_style).demap(tx_symbols_precoded);
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case db_mode.db_discard
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% normal dsp for precoded sequence == discard/omit/ignore precode
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tx_bits = PAMmapper(M,0).demap(tx_symbols);
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case db_mode.db_encoded
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% normal DB encoded data (only for 10KM)
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case db_mode.db_precoded
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eq_signal_hd = Duobinary().encode(eq_signal_hd,"M",M);
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eq_signal_hd = Duobinary().decode(eq_signal_hd,"M",M);
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end
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rx_bits = PAMmapper(M,0,"eth_style",options.eth_style).demap(eq_signal_hd);
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[~,numErrors,ber,~] = calc_ber(rx_bits.signal,tx_bits.signal,"skip_front",100,"skip_end",150,"returnErrorLocation",1);
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[evm_total,evm_lvl] = calc_evm(eq_signal_sd,tx_symbols);
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[inf_rate] = calc_air(eq_signal_sd,tx_symbols,"skip_front",10000,"skip_end",10000);
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snr(eq_signal_sd.signal,eq_noise.signal)
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eq_package.ber_vnle = ber;
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eq_package.evm_total = evm_total;
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eq_package.evm_lvl = evm_lvl;
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eq_package.inf_rate_vnle = inf_rate;
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eq_package.snr = snr(eq_signal_sd.signal,eq_noise.signal);
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if options.showAnalysis
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snr(eq_signal_sd.signal,eq_noise.signal);
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fprintf(['VNLE EVM lvl: ',repmat('%.3f ',1,numel(evm_lvl)),' \n'],evm_lvl);
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fprintf('VNLE BER: %.2e \n',ber);
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showEQNoiseSNR(tx_symbols,eq_noise,"displayname",'SNR after VNLE','fignum',301);
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showLevelHistogram(eq_signal_sd,tx_symbols,"fignum",302);
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end
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end |