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FSO data:

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- demystifyied dataset
- matched filter
- timing sync (whole sig, not symbol based)
- EQ is worse, I guess due to symbol timing recovery

Pulsef:
- can be used as matched filter now, the only thing I really changed was the sampling behavior - before it assumed that the input is always fsym, now it can be anything... fdac is output frequency for both methods
This commit is contained in:
silas (home)
2026-01-08 13:20:35 +01:00
parent 5c39a7f98a
commit 062c5dfbaf
6 changed files with 313 additions and 117 deletions
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10
Classes/00_signals/Signal.m
View File

@@ -757,11 +757,11 @@ classdef Signal
pkpos = sort(pkpos);
if mean(w) > 10 || mean(p) > 15
return
else
sequenceFound = 1;
end
% if mean(w) > 15 || mean(p) > 15
% return
% else
% sequenceFound = 1;
% end
if options.debug_plots
figure(121212);clf

244
Classes/01_transmit/Pulseformer.m
View File

@@ -43,7 +43,7 @@ classdef Pulseformer
function signalclass_out = process(obj,signalclass_in)
% actual processing of the signal (steps 1. - 3.)
signalclass_in.signal = obj.process_(signalclass_in.signal);
signalclass_in.signal = obj.process_(signalclass_in);
% append to logbook
lbdesc = 'Applied Pulseshaping';
@@ -65,109 +65,171 @@ classdef Pulseformer
% Cant be seen from outside! So put all your functions here that can/
% shall not be called from outside
function data_out = process_(obj,data_in)
%METHOD1 Summary of this method goes here
% Detailed explanation goes here
arguments(Input)
obj
data_in
end
function data_out = process_(obj, data_in_signal)
% Extract the incoming sampling rate
% Safety check: If fs is missing (e.g. raw symbols), assume it is fsym
if isprop(data_in_signal, 'fs') && ~isempty(data_in_signal.fs)
f_in = data_in_signal.fs;
else
f_in = obj.fsym;
end
arguments(Output)
data_out
end
f_out = obj.fdac;
if ~rem(obj.fdac,obj.fsym)
%ist ein Vielfaches
sps = obj.fdac / obj.fsym;
p = sps;
q = 1;
else
%ist kein Vielfaches
p = obj.fsym / gcd(obj.fdac, obj.fsym); %upsampling p->->->
q = obj.fdac/ gcd(obj.fdac, obj.fsym); %downsampling <-q
sps= q; %sps während dem pulse shaping
end
% 1. Calculate Resampling Factors (P and Q)
% We need rational approximation: f_out/f_in = p/q
[p, q] = rat(f_out / f_in);
if obj.pulse == pulseform.rc
filtertype = 'normal';
elseif pulseform.rrc
filtertype = 'sqrt';
end
% 2. Calculate SPS for the Filter Design
% The filter operates at the INTERMEDIATE rate (f_in * p).
% We need to know how many samples represent one symbol AT THAT RATE.
fs_intermediate = f_in * p;
sps_filter = fs_intermediate / obj.fsym;
%Bau das Filter (hier rc)
racos_len = obj.pulselength*2;
h = rcosdesign(obj.alpha,racos_len,sps,filtertype);
% h = h./ max(h);
% 3. Filter Design
if obj.pulse == pulseform.rc
filtertype = 'normal';
elseif obj.pulse == pulseform.rrc % assuming enum logic holds
filtertype = 'sqrt';
end
if obj.matched
h = conj(fliplr(h));
end
% Standard RRC Design
% Note: rcosdesign sps must be integer? Usually yes, but for polyphase it can handle it.
% If sps_filter is not integer, rcosdesign might complain.
% For your setup (powers of 2), it will likely be integer.
racos_len = obj.pulselength; % span in symbols
h = rcosdesign(obj.alpha, racos_len, sps_filter, filtertype);
manual_cyclic_convolution = 0;
upfirdn_convolution = 1;
% Matched Filter Flip (Complex Conjugate Time Reversal)
if obj.matched
h = conj(fliplr(h));
end
if manual_cyclic_convolution
% 4. Processing
% Apply upfirdn using the calculated P and Q
data_out_ = upfirdn(data_in_signal.signal, h, p, q);
% Apply filter the long way (from move_it)
data_in = data_in';
blen = length(data_in)*sps;
% 5. Trim Tail (Group Delay Correction)
% The delay of linear phase filter is (N-1)/2 samples @ intermediate rate
delay_samples_intermediate = (length(h) - 1) / 2;
% oversample symbol sequence
symbolov=zeros(size(data_in,1),blen);
symbolov(:,1:sps:blen-sps+1)=data_in;
H=fft(h,blen);
% Convert delay to output samples
delay_samples_out = delay_samples_intermediate / q;
% Convolution of Bit sequence with impulse response
data_out=ifft( fft(symbolov.') .* repmat( H,size(data_in,1),1 ).' ).';
data_out = circshift(data_out,[0 -(obj.pulselength*sps)]);
% We usually want to trim the "start" transient
st = floor(delay_samples_out) + 1;
if rem(obj.fdac,obj.fsym)
data_out = data_out(1:q:end);
end
% Calculate expected output length
len_out = ceil(length(data_in_signal.signal) * p / q);
end
% Cut
data_out = data_out_(st : st + len_out - 1);
end
if upfirdn_convolution
%Apply Filter using Matlab build in fctn.
data_out_ = upfirdn(data_in,h,p,q);
%cut signal, which is longer due to fir filter
st = round(p/q*racos_len/2); %we need to cut y_out
en = round(st + (length(data_in)*p/q));
data_out = data_out_(st:en);
end
if upfirdn_convolution && manual_cyclic_convolution
figure()
subplot(2,1,1)
title("Convolution vs. Upfirdn and Cut")
hold on
% plot(data_out_(1:200),'DisplayName','Matlab upfirdn');
plot(data_out(1:200),'DisplayName','By Hand cyclic convolution')
subplot(2,1,2)
hold on
plot(data_out(1:2000),'DisplayName','OUT');
plot(data_in(1:2000),'DisplayName','IN');
end
%scaling?! see pulsef module line 696
% scale = max(max([abs(real(data_out)) abs(imag(data_out))])); %find max value from real and imag part
% data_out = data_out./scale;
% data_out = data_out';
%Check output integrity
if abs(round(p/q * length(data_in)) - length(data_out)) > 4
warning('Check signal length after pulse shaping');
%disp('Check signal length after pulse shaping');
end
end
%
% function data_out = process_(obj,data_in)
% %METHOD1 Summary of this method goes here
% % Detailed explanation goes here
% arguments(Input)
% obj
% data_in
% end
%
% arguments(Output)
% data_out
% end
%
% if ~rem(obj.fdac,obj.fsym)
% %ist ein Vielfaches
% sps = obj.fdac / obj.fsym;
% p = sps;
% q = 1;
% else
% %ist kein Vielfaches
% p = obj.fsym / gcd(obj.fdac, obj.fsym); %upsampling p->->->
% q = obj.fdac/ gcd(obj.fdac, obj.fsym); %downsampling <-q
% sps= q; %sps während dem pulse shaping
% end
%
% if obj.pulse == pulseform.rc
% filtertype = 'normal';
% elseif pulseform.rrc
% filtertype = 'sqrt';
% end
%
% %Bau das Filter (hier rc)
% racos_len = obj.pulselength*2;
% h = rcosdesign(obj.alpha,racos_len,sps,filtertype);
% % h = h./ max(h);
%
% if obj.matched
% h = conj(fliplr(h));
% end
%
% manual_cyclic_convolution = 0;
% upfirdn_convolution = 1;
%
% if manual_cyclic_convolution
%
% % Apply filter the long way (from move_it)
% data_in = data_in';
% blen = length(data_in)*sps;
%
% % oversample symbol sequence
% symbolov=zeros(size(data_in,1),blen);
% symbolov(:,1:sps:blen-sps+1)=data_in;
% H=fft(h,blen);
%
% % Convolution of Bit sequence with impulse response
% data_out=ifft( fft(symbolov.') .* repmat( H,size(data_in,1),1 ).' ).';
% data_out = circshift(data_out,[0 -(obj.pulselength*sps)]);
%
% if rem(obj.fdac,obj.fsym)
% data_out = data_out(1:q:end);
% end
%
% end
%
% if upfirdn_convolution
%
% %Apply Filter using Matlab build in fctn.
%
% data_out_ = upfirdn(data_in,h,p,q);
%
% %cut signal, which is longer due to fir filter
% st = round(p/q*racos_len/2); %we need to cut y_out
% en = round(st + (length(data_in)*p/q));
% data_out = data_out_(st:en);
%
% end
%
% if upfirdn_convolution && manual_cyclic_convolution
% figure()
% subplot(2,1,1)
% title("Convolution vs. Upfirdn and Cut")
% hold on
% % plot(data_out_(1:200),'DisplayName','Matlab upfirdn');
% plot(data_out(1:200),'DisplayName','By Hand cyclic convolution')
% subplot(2,1,2)
% hold on
% plot(data_out(1:2000),'DisplayName','OUT');
% plot(data_in(1:2000),'DisplayName','IN');
% end
%
% %scaling?! see pulsef module line 696
% % scale = max(max([abs(real(data_out)) abs(imag(data_out))])); %find max value from real and imag part
% % data_out = data_out./scale;
%
% % data_out = data_out';
%
% %Check output integrity
% if abs(round(p/q * length(data_in)) - length(data_out)) > 4
% warning('Check signal length after pulse shaping');
% %disp('Check signal length after pulse shaping');
% end
%
%
% end
end

2
Classes/Moveit_wrapper.m
View File

@@ -27,7 +27,7 @@ classdef Moveit_wrapper < handle
% Ensure the function exists
if ~exist(obj.moveit_function_name, 'file')
error('Function "%s" does not exist.', obj.moveit_function_name);
error('Function "%s" does not exist. The move-it module must be on path for Matlab, otherwise the wrapper can not call it...', obj.moveit_function_name);
end
% Step 1: Get default parameters by calling moveit module

8
Functions/EQ_structures/ffe.m
View File

@@ -131,11 +131,11 @@ switch precode_mode
tx_bits_precoded = mapper.demap(tx_symbols_precoded);
rx_bits = mapper.demap(eq_signal_hd_precoded);
[~, errors_precoded, ber_precoded, ~] = calc_ber(rx_bits.signal, tx_bits_precoded.signal, "skip_front", 30000, "skip_end", 150, "returnErrorLocation", 1);
[~, errors_precoded, ber_precoded, ~] = calc_ber(rx_bits.signal, tx_bits_precoded.signal, "skip_front", 10, "skip_end", 10, "returnErrorLocation", 1);
% B) Just determine BER
rx_bits = mapper.demap(eq_signal_hd);
[bits, errors, ber, error_pos] = calc_ber(rx_bits.signal, tx_bits.signal, "skip_front", 30000, "skip_end", 150, "returnErrorLocation", 1);
[bits, errors, ber, error_pos] = calc_ber(rx_bits.signal, tx_bits.signal, "skip_front", 10, "skip_end", 10, "returnErrorLocation", 1);
case db_mode.db_precoded
% Data is precoded on TX side
@@ -143,12 +143,12 @@ switch precode_mode
eq_signal_hd_decoded = Duobinary().encode(eq_signal_hd, "M", M);
eq_signal_hd_decoded = Duobinary().decode(eq_signal_hd_decoded, "M", M);
rx_bits_decoded = mapper.demap(eq_signal_hd_decoded);
[~, errors_precoded, ber_precoded, ~] = calc_ber(rx_bits_decoded.signal, tx_bits.signal, "skip_front", 30000, "skip_end", 150, "returnErrorLocation", 1);
[~, errors_precoded, ber_precoded, ~] = calc_ber(rx_bits_decoded.signal, tx_bits.signal, "skip_front", 10, "skip_end", 10, "returnErrorLocation", 1);
% B) Omit the Coding by comparing with demapped TX symbol sequence
tx_bits_demapped = mapper.demap(tx_symbols);
rx_bits = mapper.demap(eq_signal_hd);
[bits, errors, ber, error_pos] = calc_ber(rx_bits.signal, tx_bits_demapped.signal, "skip_front", 30000, "skip_end", 150, "returnErrorLocation", 1);
[bits, errors, ber, error_pos] = calc_ber(rx_bits.signal, tx_bits_demapped.signal, "skip_front", 10, "skip_end", 10, "returnErrorLocation", 1);
end
end

139
projects/FSO_transmission/first_analysis.m
View File

@@ -1,12 +1,141 @@
datas = load("C:\Users\Silas\Downloads\FSO_FP_QCL_60umUTC\FSO_FP_QCL_60umUTC\6G_PAM4\M=4_Rs=6e9_Fs=8e10_I=225mA_RoP=28.02mW_L=31m_PS=RRC_rolloff=0.6_Mode=Rise.mat");
base = "C:\Users\Silas\Nextcloud\Dokumente\02_Ablage_Office\FSO_FP_QCL_60umUTC";
mode = 0; %0 oder 1
M = 2;
fsym = 6e9;
fs = 80e9;
all_files = dir(fullfile(base, "**/*.mat"));
rawsignal = datas.tr.lastData(1).trace.ch3.RawData;
if M == 2
tx_data = load("C:\Users\Silas\Nextcloud\Dokumente\02_Ablage_Office\FSO_FP_QCL_60umUTC\14G_PAM2\tx_info\tx_info_PAM2_14Gbd0.75RRC.mat");
filename = fullfile(base, "14G_PAM2\M=2_Rs=1.4e10_Fs=8e10_I=265mA_RoP=46.3mW_L=31m_PS=RRC_rolloff=0.75_Mode=Rise.mat");
elseif M == 4
tx_data = load("C:\Users\Silas\Nextcloud\Dokumente\02_Ablage_Office\FSO_FP_QCL_60umUTC\6G_PAM4\tx_info\tx_info_PAM4_6Gbd0.6RRC.mat");
filename = fullfile(base, "6G_PAM4\M=4_Rs=6e9_Fs=8e10_I=255mA_RoP=42.3mW_L=31m_PS=RRC_rolloff=0.6_Mode=Rise.mat");
end
Scope_sig = Electricalsignal(rawsignal,"fs",fs);
if mode == 1
[f, p] = uigetfile(fullfile(base, "**/*.mat"));
if f~=0
filename = fullfile(p,f);
end
end
datas = load(filename);
%%
str = filename;
M_ = str2double(regexp(str, 'M=([^_]+)', 'tokens', 'once'));
assert(M==M_);
fsym = str2double(regexp(str, 'Rs=([^_]+)', 'tokens', 'once'));
fs = str2double(regexp(str, 'Fs=([^_]+)', 'tokens', 'once'));
I = sscanf(char(regexp(str, 'I=([^_]+)', 'tokens', 'once')), '%f');
rop = sscanf(char(regexp(str, 'RoP=([^_]+)', 'tokens', 'once')), '%f');
L = sscanf(char(regexp(str, 'L=([^_]+)', 'tokens', 'once')), '%f');
pulseshape = string( regexp(str, 'PS=([^_]+)', 'tokens', 'once'));
rolloff = str2double(regexp(str, 'rolloff=([^_]+)', 'tokens', 'once'));
mode = string( regexp(str, 'Mode=([^\.]+)', 'tokens', 'once'));
%%
% Tx data
Bits = Informationsignal(tx_data.tx_data,"fs",fsym);
Symbols = Informationsignal(real(tx_data.tx_PAM_sym),"fs",fsym);
mapping_style = M==4; % Pam2 is like move-it; PAM-4 is different, same mapping like ETH peopled used in Zurich... hence the "eth_style" argument here and there
PM = PAMmapper(M,0,"eth_style",mapping_style); % one should rename "eth style" as this is simply a different mapping scheme
Symbols_ = PM.map(Bits) .* PM.scaling;
assert(isequal(Symbols.signal,Symbols_.signal));
Bits_ = PM.demap(Symbols);
[bits,errors,ber,errorIndice] = calc_ber(Bits_.signal,Bits.signal);
assert(ber == 0);
%% For comparison, apply pulsef on Tx Symbols
Pform = Pulseformer("fsym",fsym,"fdac",fs,"pulse","rc","pulselength",16,"alpha",rolloff);
Digi_sig_compare = Pform.process(Symbols);
MF = Pulseformer("fsym",fsym,"fdac",2*fsym,"pulse","rrc","pulselength",16,"alpha",rolloff);
Rx_sig_compare = MF.process(Digi_sig_compare);
%%
% Rx Data
traceData = datas.tr.lastData(2).trace.ch3;
%FYI: Voltage=(RawData−YReference)×YIncrement+YOrigin
scoperead_volts = (traceData.RawData - traceData.YReference) * traceData.YIncrement + traceData.YOrigin;
demystified = isequal(traceData.YData,scoperead_volts);
assert(demystified);
Scope_sig = Electricalsignal(traceData.YData,"fs",fs);
Scope_sig.plot("displayname",'raw','fignum',100);
Scope_sig.spectrum("displayname",'raw','fignum',101)
% 1) matched filter
% pulse is symmetric, hence we can use pulsef firectly as matched filter.
% It feels off (bit I think correct) that the fsym is now the output freq.!!
% -> output 2 sps to omit timing recovery!?
Pform = Pulseformer("fsym",fsym,"fdac",2*fsym,"pulse","rrc","pulselength",16,"alpha",rolloff,"matched",1);
Rx_matched = Pform.process(Scope_sig);
Rx_matched.spectrum("displayname",'Signal after matched filter','fignum',1);
% timing sync -> at this point we still have no symbol timing recovery, we
% try to do this with 2sps EQ!
[~,Rx_synced_cell,inverted,sequenceFound,sequenceStarts] = Rx_matched.tsynch("reference", Symbols, "fs_ref", fsym, "debug_plots", 1);
%% not working..
Rx_synced = Rx_synced_cell{1};
len_tr = 4096*2;
mu_ffe1 = 0.0001;
mu_ffe2 = 0.0008;
mu_ffe3 = 0.001;
mu_dc = 0.005;
mu_ffe = [mu_ffe1 mu_ffe3 mu_ffe3];
mu_dfe = 0.0004;
duob_mode = db_mode.no_db;
Rx_synced.plot("displayname",'RX: Matched+Sync+2sps','fignum',2);
Digi_sig_compare.normalize("mode","rms").spectrum("displayname",'Tx: RC-shaped','fignum',1,'normalizeTo0dB',0);
Rx_sig_compare.normalize("mode","rms").spectrum("displayname",'Tx: RC-shaped + matched filtered ','fignum',1,'normalizeTo0dB',0);
Rx_synced.normalize("mode","rms").spectrum("displayname",'RX: matched filtered + synced','fignum',1,'normalizeTo0dB',0);
if M == 2
ber_in_paper = 10^(-2.6); %fig 3a) 4 Gb/s MWIR FSO Transmission using Directly Modulated QCL and an Uncooled UTC-PD at Room-Temperature
elseif M == 4
ber_in_paper = 10^(-2.5);
end
%% -------------------- FFE --------------------
% requires some more digging what is going on :-)
eq_ffe = EQ("Ne",[50, 5, 5],"Nb",[2,0,0], ...
"training_length",len_tr,"training_loops",5,"dd_loops",5, ...
"K",2,"DCmu",mu_dc,"DDmu",[mu_ffe mu_dfe],"DFEmu",0.005, ...
"FFEmu",0,"plotfinal",0,"ideal_dfe",1);
ffe_results = ffe(eq_ffe,M,Rx_synced,Symbols,Bits, ...
"precode_mode",duob_mode,'showAnalysis',0,"postFFE",[], ...
"eth_style_symbol_mapping",mapping_style);
% ffe_results.metrics.print
fprintf('My EQ: %.1e \n',ffe_results.metrics.BER);
fprintf('Paper: %.1e \n \n',ber_in_paper);
%% -------------------- VNLE + MLSE --------------------
pf_ncoeffs = 1;
eq_v = EQ("Ne",[100, 5, 5],"Nb",[0, 0, 0], ...
"training_length",len_tr,"training_loops",5,"dd_loops",5, ...
"K",2,"DCmu",mu_dc,"DDmu",[mu_ffe mu_dfe],"DFEmu",0.005, ...
"FFEmu",0,"plotfinal",0,"ideal_dfe",1);
pf_ = Postfilter("ncoeff",pf_ncoeffs,"useBurg",1);
mlse_ = MLSE("duobinary_output",0,'M',M,'trellis_states',PAMmapper(M,0,"eth_style",mapping_style).levels);
[vnle_results, mlse_results] = vnle_postfilter_mlse(eq_v, pf_, mlse_, M, Rx_synced, Symbols, Bits, ...
"precode_mode", duob_mode, 'showAnalysis', 1, "postFFE", [], "eth_style_symbol_mapping", mapping_style);
mlse_results.metrics.print
fprintf('My EQ: %.1e \n',mlse_results.metrics.BER);
fprintf('Paper: %.1e \n \n',ber_in_paper);

19
test/matched_filter_minimal.m
View File

@@ -13,7 +13,6 @@ db_precode = 0;
db_encode = 0;
rcalpha = 0.05;
kover = 16;
vbias_rel = 0.5;
u_pi = 2.9;
@@ -47,15 +46,21 @@ if M == 6
bitpattern = bitpattern(1:end-mod(length(bitpattern),5));
end
bits = Informationsignal(bitpattern);
bits = Informationsignal(bitpattern.');
symbols = PAMmapper(M,0).map(bits);
symbols.fs = fsym;
Pform = Pulseformer("fsym",fsym,"fs",fsym,"alpha",0.6,"pulse","rrc","pulselength",64,"matched_sps",4,"output_sps",2);
Pform.process(symbols);
symbols.spectrum("displayname",'Symbols','fignum',1);
%% RRC Shaping
rcalpha = 1;
Pform = Pulseformer("fsym",fsym,"fdac",4*fsym,"pulse","rrc","pulselength",16,"alpha",rcalpha);
Digi_sig = Pform.process(symbols);
Digi_sig.spectrum("displayname",'Signal after pluse shaping','fignum',1);
%% RRC Matched Filtering
Pform = Pulseformer("fsym",fsym,"fdac",4*fsym,"pulse","rrc","pulselength",16,"alpha",rcalpha);
Rx_sig = Pform.process(Digi_sig);
Rx_sig.spectrum("displayname",'Signal after matched filter','fignum',1);
MF = Pulseformer("fsym",fsym,"fdac",fdac,"pulse","rrc","pulselength",1024,"alpha",rcalpha,"matched",0);
Digi_sig = MF.process(Digi_sig);
Digi_sig.spectrum("displayname",'Signal after shaping','fignum',1);