refactored ldpc funcs, partially completed

git-svn-id: https://svn.code.sf.net/p/freetel/code@1344 01035d8c-6547-0410-b346-abe4f91aad63

diff --git a/codec2-dev/octave/ldpc.m b/codec2-dev/octave/ldpc.m
index f30d6883f204e4815d35bdc481c4a279d6f3563d..addaafa659a7bf0e96ab4a5e6567fd66f4926c84 100644 (file)
--- a/codec2-dev/octave/ldpc.m
+++ b/codec2-dev/octave/ldpc.m
@@ -13,128 +13,79 @@
 \r
 1;\r
 \r
-function dummy\r
+function code_param = ldpc_init(rate, framesize, modulation, mod_order, mapping)\r
+    [code_param.H_rows, code_param.H_cols, code_param.P_matrix] = InitializeWiMaxLDPC( rate, framesize,  0 );\r
+    code_param.data_bits_per_frame = length(code_param.H_cols) - length( code_param.P_matrix );\r
+    code_param.S_matrix = CreateConstellation( modulation, mod_order, mapping );\r
+    code_param.bits_per_symbol = log2(mod_order);\r
 endfunction\r
 \r
-function sim_out = ldpc_proc(sim_in, resfile)\r
-\r
-Eprob = sim_in.Eprob;  \r
-\r
-framesize = sim_in.framesize;\r
-rate      = sim_in.rate;\r
-modulation = sim_in.modulation;\r
-mod_order = sim_in.mod_order;\r
-mapping   = sim_in.mapping;\r
-\r
-\r
-Lim_Ferrs = sim_in.Lim_Ferrs;\r
-Ntrials   = sim_in.Ntrials;\r
-Esvec     = sim_in.Esvec;\r
-deb       = sim_in.deb;\r
+function [codeword s] = ldpc_enc(data, code_param)\r
+        codeword = LdpcEncode( data, code_param.H_rows, code_param.P_matrix );\r
+        s = Modulate( codeword, code_param.S_matrix );\r
+endfunction\r
 \r
+function detected_data = ldpc_dec(code_param, max_iterations, demod_type, decoder_type, r, EsNo)\r
+    symbol_likelihood = Demod2D( r, code_param.S_matrix, EsNo);\r
+         \r
+    % initialize the extrinsic decoder input\r
+    input_somap_c = zeros(1, code_param.code_bits_per_frame );\r
+    bit_likelihood = Somap( symbol_likelihood, demod_type, input_somap_c );\r
+        \r
+    input_decoder_c = bit_likelihood(1:code_param.code_bits_per_frame);\r
+        \r
+    x_hat= MpDecode( -input_decoder_c, code_param.H_rows, code_param.H_cols, ...\r
+                     max_iterations, decoder_type, 1, 1);\r
+    detected_data = x_hat(max_iterations,:);\r
+endfunction\r
 \r
-demod_type = 0;\r
-decoder_type = 0;\r
-max_iterations = 100;\r
-code_param.bits_per_symbol = log2(mod_order);\r
-bps = code_param.bits_per_symbol;\r
+function sim_out = ldpc_proc(sim_in, resfile)\r
 \r
-[code_param.H_rows, code_param.H_cols, code_param.P_matrix] = InitializeWiMaxLDPC( rate, sim_in.framesize,  0 );\r
+    rate = 3/4; \r
+    framesize = 576;  \r
 \r
-code_param.data_bits_per_frame = length(code_param.H_cols) - length( code_param.P_matrix );\r
+    mod_order = 4; \r
+    modulation = 'QPSK';\r
+    mapping = 'gray';\r
 \r
-code_param.S_matrix = CreateConstellation( modulation, mod_order, mapping );\r
+    demod_type = 0;\r
+    decoder_type = 0;\r
+    max_iterations = 100;\r
 \r
-errfilename = '/home/david/codec2-dev/octave/mod_test_2000_poor_4dB.err';\r
-fin = fopen(errfilename, "rb");\r
-err = fread(fin,Inf, "short");\r
-length(err)\r
-Ntrials = floor(length(err)/framesize)\r
+    code_param = ldpc_init(rate, framesize, modulation, mod_order, mapping);\r
 \r
-for ne = 1:length(Esvec)\r
-    Es = Esvec(ne);\r
-    EsNo = 10^(Es/10);\r
+    Ntrials = 84;\r
+    EsNo=10;\r
 \r
+    Tbits = Terrs = Ferrs = 0;\r
     \r
-    Terrs = 0;  Tbits =0;  Ferrs =0;\r
-    for nn = 1: Ntrials\r
-        \r
-        data = round( rand( 1, code_param.data_bits_per_frame ) );\r
-        \r
-        codeword = LdpcEncode( data, code_param.H_rows, code_param.P_matrix );\r
-        code_param.code_bits_per_frame = length( codeword );\r
-        Nsymb = code_param.code_bits_per_frame/bps;\r
-       \r
-        % modulate\r
-        s = Modulate( codeword, code_param.S_matrix );\r
-        code_param.symbols_per_frame = length( s );\r
-     \r
-        s = Modulate(codeword, code_param.S_matrix );\r
-        code_param.symbols_per_frame = length( s );\r
-        \r
-      \r
-        variance = 1/(2*EsNo);\r
-        noise = sqrt(variance)*( randn(1,code_param.symbols_per_frame) + ...\r
-            j*randn(1,code_param.symbols_per_frame) );\r
-        a=ones(1, code_param.symbols_per_frame);  \r
-        r = a.*s + noise;\r
-\r
-        Nr = length(r); \r
-%        erasures = rand(1,Nr)<Eprob; \r
-%        r(erasures) = 0;            \r
-        \r
-        st = (nn-1)*Nr+1;\r
-        en = nn*Nr;\r
-        evec = err(st:en);\r
-        r(find(evec)) = 0;\r
+    data = [];\r
+    r = []; \r
+    for nn = 1: Ntrials        \r
+        d = round( rand( 1, code_param.data_bits_per_frame ) );\r
+        data = [data d];\r
+        [codeword, s] = ldpc_enc(d, code_param);\r
+        code_param.code_bits_per_frame = length(codeword);\r
+        code_param.symbols_per_frame = length(s);\r
+        r = [r s];\r
+    end\r
 \r
-        symbol_likelihood = Demod2D( r, code_param.S_matrix, EsNo);\r
-         \r
-        % initialize the extrinsic decoder input\r
-        input_somap_c = zeros(1, code_param.code_bits_per_frame );\r
-        bit_likelihood = Somap( symbol_likelihood, demod_type, input_somap_c );\r
-        \r
-        input_decoder_c = bit_likelihood(1:code_param.code_bits_per_frame);\r
-        \r
-        x_hat= MpDecode( -input_decoder_c, code_param.H_rows, code_param.H_cols, ...\r
-            max_iterations, decoder_type, 1, 1);\r
-        detected_data = x_hat(max_iterations,:);\r
-        error_positions = xor( detected_data(1:code_param.data_bits_per_frame), data );\r
+    for nn = 1: Ntrials        \r
+        st = (nn-1)*code_param.symbols_per_frame + 1;\r
+        en = (nn)*code_param.symbols_per_frame;\r
+        detected_data = ldpc_dec(code_param, max_iterations, demod_type, decoder_type, r(st:en), EsNo);\r
+        st = (nn-1)*code_param.data_bits_per_frame + 1;\r
+        en = (nn)*code_param.data_bits_per_frame;\r
+        error_positions = xor( detected_data(1:code_param.data_bits_per_frame), data(st:en) );\r
         Nerrs = sum( error_positions);\r
         \r
         if Nerrs>0, fprintf(1,'x'),  else fprintf(1,'.'),  end\r
-        if (rem(nn, 50)==0),  fprintf(1,'\n'),  end\r
-        \r
-        \r
-        \r
+        if (rem(nn, 50)==0),  fprintf(1,'\n'),  end    \r
         if Nerrs>0,  Ferrs = Ferrs +1;  end\r
         Terrs = Terrs + Nerrs;\r
-        Tbits = Tbits + code_param.data_bits_per_frame;\r
-        \r
-        if Ferrs > Lim_Ferrs, disp(['exit loop with #cw errors = ' ...\r
-                num2str(Ferrs)]);  break,  end\r
-    end\r
-    \r
-    TERvec(ne) = Terrs;\r
-    FERvec(ne) = Ferrs;\r
-    BERvec(ne) = Terrs/ Tbits;\r
-    Ebvec = Esvec - 10*log10(code_param.bits_per_symbol * rate);\r
-    \r
-    cparams= [code_param.data_bits_per_frame  code_param.symbols_per_frame ...\r
-        code_param.code_bits_per_frame];\r
-    \r
-    sim_out.BERvec = BERvec;\r
-    sim_out.Ebvec = Ebvec;\r
-    sim_out.FERvec = FERvec;\r
-    sim_out.TERvec  = TERvec;\r
-    sim_out.cpumins = cputime/60;\r
-    \r
-    if length(resfile)>0\r
-        save(resfile,  'sim_in',  'sim_out',  'cparams');\r
-        disp(['Saved results to ' resfile '  at Es =' num2str(Es) 'dB']);\r
+        Tbits = Tbits + code_param.data_bits_per_frame;        \r
     end\r
-  end\r
-  \r
+\r
 endfunction\r
 \r
 \r

diff --git a/codec2-dev/octave/ldpcenc.m b/codec2-dev/octave/ldpcenc.m
index 233c9a3b446a661d718b2b1551217799d9650821..3a9a51d374ac3a099544aac154494624387bbd92 100644 (file)
--- a/codec2-dev/octave/ldpcenc.m
+++ b/codec2-dev/octave/ldpcenc.m
@@ -41,9 +41,10 @@ sim_in.Ntrials =  1000;
 if exist('deb')~=1, deb = 0; end\r
 sim_in.deb =    deb;\r
 \r
-sim_out = ldpc_proc(sim_in, 'test.mat');\r
+% init enc and dec\r
+% generate bits\r
+% encode\r
+% decode\r
+% measure BER\r
+ldpc_proc(sim_in, 'test.mat');\r
 \r
-figure(100); \r
-semilogy(sim_out.Ebvec,  sim_out.BERvec)\r
-xlabel('Eb/N0')\r
-ylabel('BER')\r