silas/imdd_silas
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Add AWGN channel models and route IMDD simulation through them

Browse Source
This commit is contained in:
Silas Oettinghaus
2026-03-26 11:23:07 +01:00
parent d3235a5c9c
commit c135cb76b1
7 changed files with 167 additions and 68 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
Classes/00_signals/Informationsignal.m
View File

@@ -26,11 +26,11 @@ classdef Informationsignal < Signal
end end
% function pow = power(obj) function pow = power(obj)
%
% pow = mean(abs(obj.signal.^2),"all") ; pow = mean(abs(obj.signal.^2),"all") ;
%
% end end
end end

4
Classes/00_signals/Signal.m
View File

@@ -172,9 +172,9 @@ classdef Signal
hold on; hold on;
if isempty(options.color) if isempty(options.color)
plot(t* 1e6, sig(1:length(t)), 'DisplayName', dn, 'LineWidth', 0.1, 'Marker', 'none', 'LineStyle','-', 'MarkerSize', 0.1); plot(t* 1e6, sig(1:length(t)), 'DisplayName', dn, 'LineWidth', 0.1, 'Marker', '.', 'LineStyle','none', 'MarkerSize', 0.1);
else else
plot(t* 1e6, sig(1:length(t)), 'DisplayName', dn, 'LineWidth', 0.1, 'Marker', 'none', 'LineStyle','-', 'MarkerSize', 0.1,'Color',options.color); plot(t* 1e6, sig(1:length(t)), 'DisplayName', dn, 'LineWidth', 0.1, 'Marker', '.', 'LineStyle','none', 'MarkerSize', 0.1,'Color',options.color);
end end
% 2 c) % 2 c)
% - xlabel if not already here: time in readable format (1 ms and not 1e-3 s) % - xlabel if not already here: time in readable format (1 ms and not 1e-3 s)

32
Functions/Channel_structures/awgn_alpha_d_channel.m Normal file
View File

@@ -0,0 +1,32 @@
function signal_out = awgn_alpha_d_channel(signal_in, options)
%AWGN_ALPHA_D_CHANNEL Apply a 1 + alpha*D FIR channel followed by AWGN.
arguments
signal_in
options.alpha (1,1) double = 0
options.delay_samples (1,1) double {mustBeInteger, mustBePositive} = 1
options.snr_dB (1,1) double = 20
options.randkey = []
end
signal_out = signal_in;
taps = zeros(1, options.delay_samples + 1);
taps(1) = 1;
taps(end) = options.alpha;
signal_out.signal = filter(taps, 1, signal_in.signal, [], 1);
if isa(signal_out, 'Signal')
desc = sprintf('1 + alpha*D channel with alpha %.4f and delay %d samples', ...
options.alpha, options.delay_samples);
meta = struct( ...
'alpha', options.alpha, ...
'delay_samples', options.delay_samples);
signal_out = signal_out.logbookentry(desc, meta);
end
signal_out = awgn_channel(signal_out, ...
"snr_dB", options.snr_dB, ...
"randkey", options.randkey);
end

46
Functions/Channel_structures/awgn_channel.m
View File

@@ -1,5 +1,43 @@
function signal_out = awgn_channel(signal_in) function signal_out = awgn_channel(signal_in, options)
%AWGN_CHANNEL Apply additive white Gaussian noise to a signal object.
arguments
signal_in
options.snr_dB (1,1) double = 20
options.randkey = []
end
signal_out = signal_in; signal_out = signal_in;
x = signal_in.signal;
end
signalPower = mean(abs(x).^2, 'all'); %or use signal_in.power
if signalPower == 0
return
end
snrLinear = 10^(options.snr_dB/10);
noisePower = signalPower / snrLinear;
if isempty(options.randkey)
if isreal(x)
noise = sqrt(noisePower) * randn(size(x));
else
noise = sqrt(noisePower / 2) * (randn(size(x)) + 1i * randn(size(x)));
end
else
rs = RandStream('mt19937ar', 'Seed', options.randkey);
if isreal(x)
noise = sqrt(noisePower) * randn(rs, size(x));
else
noise = sqrt(noisePower / 2) * (randn(rs, size(x)) + 1i * randn(rs, size(x)));
end
end
signal_out.signal = x + noise;
if isa(signal_out, 'Signal')
desc = sprintf('AWGN channel with SNR %.2f dB', options.snr_dB);
meta = struct('snr_dB', options.snr_dB, 'randkey', options.randkey);
signal_out = signal_out.logbookentry(desc, meta);
end
end

6
Functions/EQ_structures/dsp_scope_signal.m
View File

@@ -47,12 +47,12 @@ function output = dsp_scope_signal(Scpe_sig_raw, Symbols, Tx_bits, options)
use_dd_mode = 1; use_dd_mode = 1;
use_ffe = 1; use_ffe = 1;
use_dfe = 1; use_dfe = 0;
use_vnle_mlse = 0; use_vnle_mlse = 0;
use_dbtgt = 0; use_dbtgt = 0;
use_dbenc = 0; use_dbenc = 0;
use_ml_mlse = 0; use_ml_mlse = 0;
showAnalysis = 0; showAnalysis = 1;
decoding_mode = []; decoding_mode = [];
addProcessingResultToDatabase = 0; %#ok<NASGU> addProcessingResultToDatabase = 0; %#ok<NASGU>
@@ -102,7 +102,7 @@ function output = dsp_scope_signal(Scpe_sig_raw, Symbols, Tx_bits, options)
"eth_style_symbol_mapping", 0); "eth_style_symbol_mapping", 0);
ffe_results.config.equalizer_structure = "ffe"; ffe_results.config.equalizer_structure = "ffe";
ffe_results.metrics.print; ffe_results.metrics.print("description",'FFE');
output.ffe_package = ffe_results; output.ffe_package = ffe_results;
end end

28
projects/IMDD_base_system/imdd_it.m
View File

@@ -15,7 +15,7 @@ close all;
if 1 if 1
uloops = struct; uloops = struct;
uloops.precomp = [0]; uloops.precomp = [0];
uloops.bitrate = [300].*1e9; %[300,330,360,390,420,450,480] [224,336,360,390,420,448] for MPI uloops.bitrate = [300].*1e9; %[300,330,360,390,420,450,480] [224,336,360,390,420,448] for MPI
% uloops.laser_wavelength = [1293,1297.5,1302,1306.5,1310,1313.4,1318,1322.7,1327.4]; % uloops.laser_wavelength = [1293,1297.5,1302,1306.5,1310,1313.4,1318,1322.7,1327.4];
@@ -23,30 +23,36 @@ if 1
uloops.M = [4]; uloops.M = [4];
uloops.link_length = 1; uloops.link_length = 1;
% uloops.link_length = [0:2:10]; % 1,2,3,5,6,8,10 % uloops.link_length = [0:2:10]; % 1,2,3,5,6,8,10
uloops.alpha = [0]; uloops.channel_alpha = [0.5];
uloops.duob_mode = db_mode.db_precoded; uloops.duob_mode = db_mode.no_db;
uloops.decoding_mode = "memoryless"; uloops.decoding_mode = "memoryless";
uloops.channel_mode = "awgn_alphad";
uloops.channel_snr_dB = [20:-2:0];
wh = DataStorage(uloops); wh = DataStorage(uloops);
wh.addStorage("ber"); wh.addStorage("ber");
wh = submit_handle(@imdd_model,wh,"parallel",0); wh = submit_handle(@imdd_model,wh,"parallel",1);
end end
%% %%
figure figure
hold on hold on
for alpha = uloops.alpha for alpha = uloops.channel_alpha
a=wh.getStoValue('ber',0, [300].*1e9 , 1293, 4, uloops.link_length,alpha,uloops.duob_mode,uloops.decoding_mode); a=wh.getStoValue('ber',0, [300].*1e9 , 1293, 4, uloops.link_length,alpha,uloops.duob_mode,uloops.decoding_mode,uloops.channel_mode,uloops.channel_snr_dB);
% ffe = cellfun(@(x) x.ffe_results.metrics.BER, a); gmi_ffe = cellfun(@(x) x.ffe_results.metrics.GMI, a);
ffe = cellfun(@(x) x.dbt_results.metrics.BER, a); alpha_ffe = cellfun(@(x) x.ffe_results.metrics.Alpha, a);
plot(uloops.link_length,ffe,'DisplayName',sprintf('Alpha: %d',alpha),'LineStyle','-','HandleVisibility','on');
gmi_mlse = cellfun(@(x) x.mlse_results.metrics.GMI, a);
plot(uloops.channel_snr_dB,gmi_ffe,'DisplayName',sprintf(''),'LineStyle','-','HandleVisibility','on');
plot(uloops.channel_snr_dB,gmi_mlse,'DisplayName',sprintf(''),'LineStyle','-','HandleVisibility','on');
end end
set(gca, 'YScale', 'log'); set(gca, 'YScale', 'log');
ylim([5e-5 0.4]); % ylim([5e-5 0.5]);
yline([3.8e-3, 2e-2],'HandleVisibility','off'); % yline([3.8e-3, 2e-2],'HandleVisibility','off');
legend legend
beautifyBERplot() beautifyBERplot()
ylabel('BER'); ylabel('BER');

109
projects/IMDD_base_system/imdd_model.m
View File

@@ -32,6 +32,10 @@ tx_bw_nyquist = 0.8;
% Channel % Channel
link_length = 1; link_length = 1;
channel_mode = "physical";
channel_snr_dB = 20;
channel_alpha = 0;
channel_delay_symbols = 1;
% RX % RX
rop = -8; rop = -8;
@@ -46,7 +50,7 @@ dfe_order = [0 0 0];
pf_ncoeffs = 1; pf_ncoeffs = 1;
alpha = 0; eml_alpha = 0;
len_tr = 4096*2; len_tr = 4096*2;
@@ -95,15 +99,12 @@ if fsym_ ~= fsym
end end
f_nyquist = fsym/2; f_nyquist = fsym/2;
Pform = Pulseformer("fsym",fsym,"fdac",4*fsym,"pulse","rc","pulselength",16,"alpha",rcalpha); Pform = Pulseformer("fsym",fsym,"fdac",4*fsym,"pulse","rc","pulselength",16,"alpha",rcalpha);
[Digi_sig,Symbols,Tx_bits] = PAMsource(... [Digi_sig,Symbols,Tx_bits] = PAMsource(...
"fsym",fsym,"M",M,"order",18,"useprbs",0,... "fsym",fsym,"M",M,"order",16,"useprbs",0,...
"fs_out",fdac,... "fs_out",fdac,...
"applyclipping",0,"clipfactor",1.5,... "applyclipping",0,"clipfactor",1.5,...
"applypulseform",apply_pulsef,"pulseformer",Pform,... "applypulseform",apply_pulsef,"pulseformer",Pform,...
@@ -113,52 +114,74 @@ Pform = Pulseformer("fsym",fsym,"fdac",4*fsym,"pulse","rc","pulselength",1
Digi_sig.spectrum("displayname",'Digi Spectrum','fignum',10,'normalizeTo0dB',1); Digi_sig.spectrum("displayname",'Digi Spectrum','fignum',10,'normalizeTo0dB',1);
%%%%% AWG
% El_sig = M8199A("kover",kover).process(Digi_sig);
El_sig = AWG("fdac",fdac,"f_cutoff",fsym,"lpf_active",0,"kover",kover,"bit_resolution",12,"upsampling_method","samplehold","precomp_sinc_rolloff",1).process(Digi_sig);
% El_sig.spectrum("displayname",'Digi Spectrum','fignum',100,'normalizeTo0dB',0);
% El_sig = El_sig.setPower(0,"dBm");
%%%%% Low-pass el. components %%%%%% channel_mode = lower(string(channel_mode));
tx_bwl = tx_bw_nyquist.*f_nyquist;
% tx_bwl = 80e9;
El_sig = Filter('filtdegree',4,"f_cutoff",tx_bwl,"fs",fdac*kover,"filterType",filtertypes.butterworth,"active",true).process(El_sig);
% El_sig.spectrum("displayname",'Digi Spectrum','fignum',100,'normalizeTo0dB',1);
%%%%% Electrical Driver Amplifier %%%%%% switch channel_mode
% El_sig = Amplifier("amp_mode","ideal_no_noise","gain_mode","gain","amplification_db",3).process(El_sig); case "physical"
El_sig = El_sig.normalize("mode","oneone");
scaling = 0.6*(u_pi/2-abs(vbias-u_pi/2));
El_sig = El_sig .* scaling;
%%%%% MODULATE E/O CONVERSION %%%%%% %%%%% AWG
[Opt_sig] = EML("mode",eml_mode.im_cosinus,"power",3,"fsimu",El_sig.fs,"lambda",laser_wavelength,"bias",vbias,"u_pi",u_pi,"linewidth",laser_linewidth,"randomkey",random_key+1,"alpha",alpha).process(El_sig); % El_sig = M8199A("kover",kover).process(Digi_sig);
El_sig = AWG("fdac",fdac,"f_cutoff",fsym,"lpf_active",0,"kover",kover,"bit_resolution",12,"upsampling_method","samplehold","precomp_sinc_rolloff",1).process(Digi_sig);
% El_sig.spectrum("displayname",'Digi Spectrum','fignum',100,'normalizeTo0dB',0);
% El_sig = El_sig.setPower(0,"dBm");
% Opt_sig.spectrum("displayname",'Opt Spectrum','fignum',10,'normalizeTo0dB',1); %%%%% Low-pass el. components %%%%%%
tx_bwl = tx_bw_nyquist.*f_nyquist;
% tx_bwl = 80e9;
El_sig = Filter('filtdegree',4,"f_cutoff",tx_bwl,"fs",fdac*kover,"filterType",filtertypes.butterworth,"active",true).process(El_sig);
% El_sig.spectrum("displayname",'Digi Spectrum','fignum',100,'normalizeTo0dB',1);
Opt_sig = Fiber("fsimu",Opt_sig.fs,"fiber_length",link_length,"alpha",0.3,"D",0,"lambda0",1310,"gamma",0,"Dslope",0.07).process(Opt_sig); %%%%% Electrical Driver Amplifier %%%%%%
% El_sig = Amplifier("amp_mode","ideal_no_noise","gain_mode","gain","amplification_db",3).process(El_sig);
El_sig = El_sig.normalize("mode","oneone");
scaling = 0.6*(u_pi/2-abs(vbias-u_pi/2));
El_sig = El_sig .* scaling;
%%%%%% ROP %%%%%% %%%%% MODULATE E/O CONVERSION %%%%%%
Rx_sig = Amplifier("amp_mode","ideal_no_noise","gain_mode","output_power","amplification_db",rop).process(Opt_sig); [Opt_sig] = EML("mode",eml_mode.im_cosinus,"power",3,"fsimu",El_sig.fs,"lambda",laser_wavelength,"bias",vbias,"u_pi",u_pi,"linewidth",laser_linewidth,"randomkey",random_key+1,"alpha",eml_alpha).process(El_sig);
%%%%%% PD Square Law %%%%%% % Opt_sig.spectrum("displayname",'Opt Spectrum','fignum',10,'normalizeTo0dB',1);
Rx_sig = Photodiode("fsimu",fdac*kover,"dark_current",2e-08,"responsivity",1,"temperature",20,"nep",1.8e-11).process(Rx_sig); Opt_sig = Fiber("fsimu",Opt_sig.fs,"fiber_length",link_length,"alpha",0.3,"D",0,"lambda0",1310,"gamma",0,"Dslope",0.07).process(Opt_sig);
%%%%%% Low-pass RX (PD, El. Connectors and Scope %%%%%% %%%%%% ROP %%%%%%
rx_bwl = rx_bw_nyquist.*f_nyquist; Rx_sig = Amplifier("amp_mode","ideal_no_noise","gain_mode","output_power","amplification_db",rop).process(Opt_sig);
% rx_bwl = 80e9;
Rx_sig = Filter('filtdegree',4,"f_cutoff",rx_bwl,"fs",fdac*kover,"filterType",filtertypes.butterworth,"active",true).process(Rx_sig);
% %%%%%% Low-pass Scope %%%%%% %%%%%% PD Square Law %%%%%%
Lp_scpe = Filter('filtdegree',4,"f_cutoff",110e9,"fs",fadc,"filterType",filtertypes.butterworth,"active",true); Rx_sig = Photodiode("fsimu",fdac*kover,"dark_current",2e-08,"responsivity",1,"temperature",20,"nep",1.8e-11).process(Rx_sig);
% Rx_sig.spectrum("displayname",'Analog Rx Spectrum','fignum',100,'normalizeTo0dB',1); %%%%%% Low-pass RX (PD, El. Connectors and Scope %%%%%%
rx_bwl = rx_bw_nyquist.*f_nyquist;
% rx_bwl = 80e9;
Rx_sig = Filter('filtdegree',4,"f_cutoff",rx_bwl,"fs",fdac*kover,"filterType",filtertypes.butterworth,"active",true).process(Rx_sig);
%%%%%% Scope %%%%%% % %%%%%% Low-pass Scope %%%%%%
Scpe_sig = Scope("fsimu",fdac*kover,"fadc",fadc,... Lp_scpe = Filter('filtdegree',4,"f_cutoff",110e9,"fs",fadc,"filterType",filtertypes.butterworth,"active",true);
"delay",0,"fixed_delay",0,"filtertype",filtertypes.butterworth,...
"samplingdelay",0,"rand_samplingdelay",0,"freq_offset",0,"samp_jitter",0,... % Rx_sig.spectrum("displayname",'Analog Rx Spectrum','fignum',100,'normalizeTo0dB',1);
"adcresolution",8,"quantbuffer",0.1,'block_dc',1,'lpf_active',1,'H_lpf',Lp_scpe).process(Rx_sig);
%%%%%% Scope %%%%%%
Rx_sig = Scope("fsimu",fdac*kover,"fadc",fadc,...
"delay",0,"fixed_delay",0,"filtertype",filtertypes.butterworth,...
"samplingdelay",0,"rand_samplingdelay",0,"freq_offset",0,"samp_jitter",0,...
"adcresolution",8,"quantbuffer",0.1,'block_dc',1,'lpf_active',1,'H_lpf',Lp_scpe).process(Rx_sig);
case "awgn"
Rx_sig = awgn_channel(Digi_sig, ...
"snr_dB", channel_snr_dB, ...
"randkey", random_key + 2);
case {"awgn_alphad", "awgn_1alphad", "awgn_1_plus_alpha_d"}
delaySamples = max(1, round(channel_delay_symbols * Digi_sig.fs / fsym));
Rx_sig = awgn_alpha_d_channel(Digi_sig, ...
"alpha", channel_alpha, ...
"delay_samples", delaySamples, ...
"snr_dB", channel_snr_dB, ...
"randkey", random_key + 2);
otherwise
error('Unknown channel_mode "%s". Supported: physical, awgn, awgn_alphaD.', channel_mode);
end
txPulseformer = []; txPulseformer = [];
if apply_pulsef if apply_pulsef
@@ -171,9 +194,9 @@ dspParameters.mu_ffe = mu_ffe;
dspParameters.mu_dfe = mu_dfe; dspParameters.mu_dfe = mu_dfe;
dspParameters.mu_dc = mu_dc; dspParameters.mu_dc = mu_dc;
dspParameters.use_ffe = 1; dspParameters.use_ffe = 1;
dspParameters.use_dfe = 1; dspParameters.use_dfe = 0;
dspParameters.use_vnle_mlse = 1; dspParameters.use_vnle_mlse = 1;
dspParameters.use_dbtgt = 1; dspParameters.use_dbtgt = 0;
dspParameters.use_dbenc = 0; dspParameters.use_dbenc = 0;
dspParameters.use_ml_mlse = 0; dspParameters.use_ml_mlse = 0;
dspParameters.showAnalysis = 0; dspParameters.showAnalysis = 0;
@@ -187,7 +210,7 @@ dspParameters.ffe_order_dbtgt = [50, 0, 0];
dspParameters.dfe_order_dbtgt = dfe_order; dspParameters.dfe_order_dbtgt = dfe_order;
dspParameters.decoding_mode = decoding_mode; dspParameters.decoding_mode = decoding_mode;
scopeOutput = dsp_scope_signal(Scpe_sig, Symbols, Tx_bits, ... scopeOutput = dsp_scope_signal(Rx_sig, Symbols, Tx_bits, ...
"fsym", fsym, ... "fsym", fsym, ...
"M", M, ... "M", M, ...
"duob_mode", duob_mode, ... "duob_mode", duob_mode, ...