Creating an ACM system for DVB-S2
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Hi,
I am currently working on a project to create a ACM techquie function as per the instruction below:
Design an ACM technique for the DVB‐S2 transmission by adding a MATLAB function to the simulator developed in Task 3, selecting the modulation and code rates adaptively according to the LDPC rate table given in Task 3 Question 1.
The table for the LDPC rates are as follows:
The current code I have is as follows:
clc
clear all
close all
tic
%Elapsed time is 6860.512059 seconds.
N_iter=100; % number of iterations for each SNR
figure(1)
for codecase=1:4
[R, nBCH, kBCH, genBCH, M] = getbchparameters(codecase);
fprintf("Case %d: LDPC code rate =%s %dPSK",codecase, rats(R),M);
switch codecase
case 1
Eb_N0=[(-4:1:-1),(-0.9:0.1:0),(0.1:0.05:0.4),(0.41:0.01:0.5)];
case 2
Eb_N0=[(-4:1:3),(3.1:0.1:3.6),(3.61:0.01:3.7),(3.705:0.005:3.8)];
case 3
Eb_N0=[(-4:1:3),(3.1:0.1:3.5),(3.51:0.01:4)];
case 4
Eb_N0=[(-4:1:5),(5.2:0.2:6.2),(6.21:0.01:6.34),(6.345:0.005:6.400)];
end
% BCH Encoding and Decoding Objects
% Encoding
hBCHEnc=comm.BCHEncoder();
hBCHEnc.CodewordLength = nBCH;
hBCHEnc.MessageLength = kBCH;
hBCHEnc.PrimitivePolynomialSource='Property';
hBCHEnc.GeneratorPolynomialSource='Property';
hBCHEnc.GeneratorPolynomial = genBCH;
hBCHEnc.PrimitivePolynomial = de2bi(65581, 'left-msb');
hBCHEnc.CheckGeneratorPolynomial= false;
% Decoding
hBCHDec=comm.BCHDecoder();
hBCHDec.CodewordLength = nBCH;
hBCHDec.MessageLength = kBCH;
hBCHDec.PrimitivePolynomialSource='Property';
hBCHDec.GeneratorPolynomialSource='Property';
hBCHDec.GeneratorPolynomial = genBCH;
hBCHDec.PrimitivePolynomial = de2bi(65581, 'left-msb');
hBCHDec.CheckGeneratorPolynomial= false;
% LDPC Encoding and Decoding Objects
hEnc = comm.LDPCEncoder('ParityCheckMatrix',dvbs2ldpc(R));
hDec = comm.LDPCDecoder('ParityCheckMatrix',dvbs2ldpc(R));
% Modulation Object
hMod = comm.PSKModulator(M, 'BitInput',true);
n=1;
BER=zeros(size(Eb_N0));
for eb_no=Eb_N0
[R, eb_no, M]
gamma=eb_no+10*log10(log2(M)*R);
% AWGN
hChan = comm.AWGNChannel(...
'NoiseMethod','Signal to noise ratio (SNR)','SNR',gamma);
% Demodulation
hDemod = comm.PSKDemodulator(M, 'BitOutput',true,...
'DecisionMethod','Approximate log-likelihood ratio', ...
'Variance', 1/10^(hChan.SNR/10));
% For BER calculations
hError = comm.ErrorRate;
EE=zeros(1,N_iter);
for counter = 1:N_iter
reset(hBCHEnc);
reset(hBCHDec);
reset(hEnc);
reset(hDec);
%reset(hInt);
%reset(hDeint);
reset(hError);
%data = logical(randi([0,1],k_1dpc, 1)); % Random bit generation
data = logical(randi([0,1],kBCH, 1));
BCHdata=step(hBCHEnc,data); % BCH encoding
%encodedData = step(hEnc,data); % LDPC encoding
%encodedData = step(hEnc,BCHdata); % LDPC encoding
LDPCData = step(hEnc,BCHdata);
interleaverData = matintrlv(LDPCData, 21600, 3);
%encodedData = step(hInt,LDPCData) % Interleaver
modSignal = step(hMod, interleaverData); % Modulation
receivedSignal = step(hChan, modSignal); % Transmission over the channel
demodSignal = step(hDemod, receivedSignal); % Demodulation
%RBits=step(hDec, demodSignal); % BHC decoding
%Deint = step(hDeint, demodSignal); % Deinterleaver
DeinterleaverData = matdeintrlv(demodSignal, 21600, 3);
LDPCBits = step(hDec, DeinterleaverData); % LDPC decoding
RBits=step(hBCHDec,LDPCBits); % BHC decoding
errorStats = step(hError, data, RBits); % BER calculations
EE(1,counter)=errorStats(1);
end
BER(1,n)=mean(EE(1,:)); % Averaging over iterations
n=n+1;
end
semilogy(Eb_N0,BER)
hold on
end
%Case 5&6:Uncoded
for codecase=5:6
switch codecase
case 5
Eb_N0=(-4:1:13);
M=4;
case 6
Eb_N0=(-4:1:13);
M=8;
end
fprintf("Case %d:Uncoded, %dPSK",codecase,M);
% Modulation Object
hMod = comm.PSKModulator(M, 'BitInput',true);
n=1;
BER=zeros(size(Eb_N0));
for eb_no=Eb_N0
[1, gamma, M]
gamma=eb_no+10*log10(log2(M));
hChan = comm.AWGNChannel(...
'NoiseMethod','Signal to noise ratio (SNR)','SNR',gamma);
hDemod = comm.PSKDemodulator(M, 'BitOutput',true,...
'DecisionMethod','Approximate log-likelihood ratio', ...
'Variance', 1/10^(hChan.SNR/10));
hError = comm.ErrorRate; % For BER calculations
EE=zeros(1,N_iter);
for counter = 1:N_iter
reset(hError);
data = logical(randi([0,1],64800, 1)); % Random bit generation
encodedData = data;
modSignal = step(hMod, encodedData); % Modulation
receivedSignal = step(hChan, modSignal); % Transmission over the channel
demodSignal = step(hDemod, receivedSignal); % Demodulation
hard_symbols = (demodSignal > 0) + (demodSignal <= 0).*(-1); % Hard Decoding without LDPC
demodSignal = (hard_symbols == -1);
receivedBits = demodSignal;
errorStats = step(hError, data, receivedBits); % BER calculations
EE(1,counter)=errorStats(1);
end
BER(1,n)=mean(EE(1,:)); % Averaging over iterations
n=n+1;
end
semilogy(Eb_N0,BER)
hold on
end
grid on;
title('LDPC simulation'); xlabel('Eb/N_0 [dB]'); ylabel('BER');
legend('R=2/5,QPSK','R=9/10,QPSK','R=2/3,8PSK','R=8/9,8PSK','Uncoded, QPSK','Uncoded, 8PSK');
toc
%--------------------------------------------------------------------------
function [R, nBCH, kBCH, genBCH, M] = getbchparameters(i)
table6a = [2/5 25728 25920 12 64800 4
9/10 58192 58320 8 64800 4
2/3 43040 43200 10 64800 8
8/9 57472 57600 8 64800 8];
R = table6a(i,1);
kBCH = table6a(i,2);
nBCH = table6a(i,3);
tBCH = table6a(i,4);
M = table6a(i,6);
BCH_PriPoly=[1 0 0 0 0 0 0 0 0 0 0 1 0 1 1 0 1;...
1 0 0 0 0 0 0 0 1 0 1 1 1 0 0 1 1;...
1 0 0 0 0 1 1 1 1 1 0 1 1 1 1 0 1;...
1 0 1 0 1 1 0 1 0 0 1 0 1 0 1 0 1;...
1 0 0 0 1 1 1 1 1 0 0 1 0 1 1 1 1;...
1 1 1 1 1 0 1 1 1 1 0 1 1 0 1 0 1;...
1 1 0 1 0 1 1 1 1 0 1 1 0 0 1 0 1;...
1 0 1 1 1 0 0 1 1 0 1 1 0 0 1 1 1;...
1 0 0 0 0 1 1 1 0 1 0 1 0 0 0 0 1;...
1 0 1 1 1 0 1 0 1 1 0 1 0 0 1 1 1;...
1 0 0 1 1 1 0 1 0 0 0 1 0 1 1 0 1;...
1 0 0 0 1 1 0 1 0 1 1 1 0 0 0 1 1];
genBCH=BCH_PriPoly(1,:);
for i=1:tBCH-1
genBCH=conv(genBCH,BCH_PriPoly(i+1,:));
end
genBCH=mod(genBCH,2);
end
Any help with this would be appreciated.
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2021-10-29
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