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Diffstat (limited to 'octave/qam16_test.m')
| -rw-r--r-- | octave/qam16_test.m | 141 |
1 files changed, 0 insertions, 141 deletions
diff --git a/octave/qam16_test.m b/octave/qam16_test.m deleted file mode 100644 index c613214..0000000 --- a/octave/qam16_test.m +++ /dev/null @@ -1,141 +0,0 @@ -% qam16_test.m -% David Rowe May 2020 -% -% Octave symbol rate QAM16/LDPC experiments - -% Libraries we need - -1; -qam16; -ldpc; - -function test_qam16(fg=2) - printf("QAM16 ----------------------------------------\n"); - - mod_order = 16; bps = log2(mod_order); - modulation = 'QAM'; mapping = ""; demod_type = 0; decoder_type = 0; - max_iterations = 100; EsNo_dec = 10; - qam16_const = [ - 1 + j, 1 + j*3, 3 + j, 3 + j*3; - 1 - j, 1 - j*3, 3 - j, 3 - j*3; - -1 + j, -1 + j*3, -3 + j, -3 + j*3; - -1 - j, -1 - j*3, -3 - j, -3 - j*3]; - rms = sqrt(qam16_const(:)'*qam16_const(:)/16); - qam16_const = qam16_const/rms; - constellation_source = 'custom'; - test_qam16_mod_demod(qam16_const); - - load HRA_504_396.txt - if strcmp(constellation_source,'cml') - code_param = ldpc_init_user(HRA_504_396, modulation, mod_order, mapping); - else - code_param = ldpc_init_user(HRA_504_396, modulation, mod_order, mapping, reshape(qam16_const,1,16)); - end - rate = code_param.ldpc_data_bits_per_frame/code_param.ldpc_coded_bits_per_frame; - - printf("EbNodB Tbits Terrs BER Tcbits Tcerrs Perrs CBER CPER\n"); - EbNodBvec = 3:10; Ntrials = 1000; - for i=1:length(EbNodBvec) - EbNodB = EbNodBvec(i); - EsNodB = EbNodB + 10*log10(rate) + 10*log10(bps); EsNodBvec(i) = EsNodB; - EsNo = 10^(EsNodB/10); - variance = 1/EsNo; - Terrs = Tbits = 0; Tcerrs = 0; Tcbits = 0; Perrs = 0; rx_symbols_log = []; - for nn = 1:Ntrials - tx_bits = round(rand(1, code_param.ldpc_data_bits_per_frame)); - [tx_codeword, tx_symbols] = ldpc_enc(tx_bits, code_param); - noise = sqrt(variance*0.5)*(randn(1,length(tx_symbols)) + j*randn(1,length(tx_symbols))); - rx_symbols = tx_symbols + noise; - rx_symbols_log = [rx_symbols_log rx_symbols]; - - % uncoded decode/demod and count errors - rx_codeword = zeros(1,code_param.ldpc_coded_bits_per_frame); - for s=1:length(rx_symbols) - rx_codeword((s-1)*bps+1:s*bps) = qam16_demod(qam16_const,rx_symbols(s)); - end - Nerr = sum(xor(tx_codeword,rx_codeword)); - Terrs += Nerr; - Tbits += code_param.ldpc_coded_bits_per_frame; - - % LDPC demod/decode and count errors - dec_rx_codeword = ldpc_dec(code_param, max_iterations, demod_type, decoder_type, rx_symbols, EsNo_dec, ones(1,length(rx_symbols))); - errors_positions = xor(tx_bits, dec_rx_codeword(1:code_param.ldpc_data_bits_per_frame)); - Ncerr = sum(errors_positions); - Tcbits += code_param.ldpc_data_bits_per_frame; Tcerrs += Ncerr; - if Ncerr Perrs++; end - end - figure(fg); clf; plot(rx_symbols_log,"."); axis([-1.5 1.5 -1.5 1.5]); drawnow; - printf("%5.1f %6d %6d %5.2f %6d %6d %6d %5.2f %5.2f\n", - EbNodB, Tbits, Terrs, Terrs/Tbits, Tcbits, Tcerrs, Perrs, Tcerrs/Tcbits, Perrs/Ntrials); - ber(i) = Terrs/Tbits; cber(i) = Tcerrs/Tcbits; cper(i) = Perrs/Ntrials; - end - print("qam64_scatter.png","-dpng"); - - figure(fg+1); clf; title('QAM16 Uncoded'); - uncoded_EbNodBvec = EbNodBvec + 10*log10(rate); - ber_theory = ber_qam(uncoded_EbNodBvec); - semilogy(uncoded_EbNodBvec,ber_theory,'b+-;uncoded QAM16 BER theory;','markersize', 10, 'linewidth', 2); hold on; - semilogy(uncoded_EbNodBvec,ber+1E-10,'g+-;uncoded QAM16 BER;','markersize', 10, 'linewidth', 2); hold on; - grid; axis([min(uncoded_EbNodBvec) max(uncoded_EbNodBvec) 1E-5 1]); xlabel('Uncoded Eb/No (dB)'); - print("qam16_uncoded_ber.png","-dpng"); - - figure(fg+2); clf; title('QAM16 with LDPC (504,396)'); - semilogy(EbNodBvec,cber+1E-10,'b+-;QAM16 coded BER;','markersize', 10, 'linewidth', 2); hold on; - semilogy(EbNodBvec,cper+1E-10,'g+-;QAM16 coded PER;','markersize', 10, 'linewidth', 2); hold off; - grid; axis([min(EbNodBvec) max(EbNodBvec) 1E-5 1]); xlabel('Eb/No (dB)'); - - figure(fg+3); clf; title('QAM16 with LDPC (504,396)'); - semilogy(EsNodBvec,cber+1E-10,'b+-;QAM16 coded BER;','markersize', 10, 'linewidth', 2); hold on; - semilogy(EsNodBvec,cper+1E-10,'g+-;QAM16 coded PER;','markersize', 10, 'linewidth', 2); hold off; - grid; axis([min(EsNodBvec) max(EsNodBvec) 1E-5 1]); xlabel('Es/No (dB)'); - print("qam16_504_396.png","-dpng"); -endfunction - - -% Thanks Bill VK5DSP, for the QAM BER functions - -function p = ber_qam(ebn0) - % Calculate the bit error rate (BER) for square 16QAM in AWGN - % given the Eb/N0 in dB, ebn0 can be a scalar or vector - % (assuming coherent detection, uncoded) - % [section 5.3 Webb and Hanzo text] - - e = 4*10.^(ebn0/10); % Es/N0 vector in linear - b2 = qfn(sqrt(e/5)); - b1 = (qfn(sqrt(e/5)) + qfn(3*sqrt(e/5)))/2; - p = (b1+b2)/2; -endfunction - -function tail=qfn(a) - % Usage: tail=qfn(a) - % where: tail=area under the tail of the normal dist. from a to inf. - % for zero mean, unit variance distribution - % - % If no argument is given, plot Q(x) for x = 0 to 5 - - % use erfc instead of 1-erf to avoid truncation errors! April 2010 - - fact = 1 / sqrt(2); - if exist('a') - - % tail = 0.5 * ( 1 - erf(a * fact)); - tail = 0.5 * erfc(a * fact); - else - x=(0: 0.1: 6); semilogy(x, 0.5*( erfc(x * fact))); - title('Q function plot'); - xlabel('x'); ylabel('Q(x)'); - end -endfunction - - -% -------------------------------------------------------------------------------- -% START SIMULATIONS -% -------------------------------------------------------------------------------- - -more off; -format; - -% Start CML library (see CML set up instructions in ldpc.m) -init_cml(); - -test_qam16(1) |