single point Octave coh psk sim working again

git-svn-id: https://svn.code.sf.net/p/freetel/code@2109 01035d8c-6547-0410-b346-abe4f91aad63

diff --git a/codec2-dev/octave/cohpsk.m b/codec2-dev/octave/cohpsk.m
index 2cfa41ce5ed47378e145d1f2b77ca8b769d59426..849efe298a23c98549910d16efc62487aaf291fb 100644 (file)
--- a/codec2-dev/octave/cohpsk.m
+++ b/codec2-dev/octave/cohpsk.m
@@ -190,7 +190,7 @@ end
 
 % Symbol rate processing for rx side (demodulator) -------------------------------------------------------
 
-function [rx_symb rx_bits amp_ phi_ EsNo_ cohpsk] = qpsk_symbols_to_bits(cohpsk, ct_symb_buf)
+function [rx_symb rx_bits rx_symb_linear amp_ phi_ EsNo_ cohpsk] = qpsk_symbols_to_bits(cohpsk, ct_symb_buf)
     framesize     = cohpsk.framesize;
     Nsymb         = cohpsk.Nsymb;
     Nsymbrow      = cohpsk.Nsymbrow;
@@ -211,7 +211,7 @@ function [rx_symb rx_bits amp_ phi_ EsNo_ cohpsk] = qpsk_symbols_to_bits(cohpsk,
     for c=1:Nc
       corr = pilot2(:,c)' * ct_symb_buf(sampling_points,c);
       mag  = sum(abs(ct_symb_buf(sampling_points,c)));
-
+      
       phi_(:, c) = angle(corr);
       amp_(:, c) = mag/length(sampling_points);
     end
@@ -691,6 +691,8 @@ function sim_out = ber_test(sim_in)
         phase_offset = 0;
         w_offset     = pi/16;
 
+        ct_symb_buf = zeros(2*Nsymbrowpilot, Nc);
+
         % simulation starts here-----------------------------------
  
         for nn = 1:Ntrials+2
@@ -701,11 +703,13 @@ function sim_out = ber_test(sim_in)
               tx_bits = round(rand(1,framesize));                       
             end
 
-            [s_ch tx_bits prev_sym_tx] = bits_to_qpsk_symbols(sim_in, tx_bits, code_param, prev_sym_tx);
+            [tx_symb tx_bits prev_sym_tx] = bits_to_qpsk_symbols(sim_in, tx_bits, code_param, prev_sym_tx);
    
             tx_bits_buf(1:framesize) = tx_bits_buf(framesize+1:2*framesize);
             tx_bits_buf(framesize+1:2*framesize) = tx_bits;
 
+            s_ch = tx_symb;
+
             % HF channel simulation  ------------------------------------
             
             hf_fading = ones(1,Nsymb);
@@ -752,14 +756,17 @@ function sim_out = ber_test(sim_in)
 
             s_ch = s_ch + noise;
             
-            [rx_symb rx_bits amp_ phi_ EsNo_ sim_in] = qpsk_symbols_to_bits(sim_in, s_ch);                                 
+            ct_symb_buf(1:Nsymbrowpilot,:) = ct_symb_buf(Nsymbrowpilot+1:2*Nsymbrowpilot,:);
+            ct_symb_buf(Nsymbrowpilot+1:2*Nsymbrowpilot,:) = s_ch;
+
+            [rx_symb rx_bits rx_symb_linear amp_ phi_ EsNo_ sim_in] = qpsk_symbols_to_bits(sim_in, ct_symb_buf(1:Nsymbrowpilot+Npilotsframe,:));                                 
 
             phi_log = [phi_log; phi_];
             amp_log = [amp_log; amp_];
 
-            % Wait until we have 3 frames to do pilot assisted phase estimation
+            % Wait until we have enough frames to do pilot assisted phase estimation
 
-            if nn > 2 
+            if nn > 1
               rx_symb_log = [rx_symb_log rx_symb_linear];
               EsNo__log = [EsNo__log EsNo_];
 
@@ -796,8 +803,8 @@ function sim_out = ber_test(sim_in)
             if verbose 
               av_tx_pwr = (s_ch_tx_log * s_ch_tx_log')/length(s_ch_tx_log);
 
-              printf("EsNo est (dB): %3.1f Terrs: %d Tbits: %d BER %4.2f QPSK BER theory %4.2f av_tx_pwr: %3.2f",
-                       mean(10*log10(EsNo__log)), Terrs, Tbits,
+              printf("EsNo (dB): %3.1f Terrs: %d Tbits: %d BER %5.3f QPSK BER theory %5.3f av_tx_pwr: %3.2f",
+                     EsNodB, Terrs, Tbits,
                        Terrs/Tbits, 0.5*erfc(sqrt(EsNo/2)), av_tx_pwr);
               if ldpc_code
                   printf("\n LDPC: Terrs: %d BER: %4.2f Ferrs: %d FER: %4.2f", 

diff --git a/codec2-dev/octave/tcohpsk.m b/codec2-dev/octave/tcohpsk.m
index 1088b2594c0ea991a2ec6ae1de23c2dd849461a6..58e805c23db87ef2ce81dab4540d56313f43ba47 100644 (file)
--- a/codec2-dev/octave/tcohpsk.m
+++ b/codec2-dev/octave/tcohpsk.m
@@ -209,7 +209,7 @@ for i=1:frames
   ct_symb_ff_log = [ct_symb_ff_log; acohpsk.ct_symb_ff_buf(1:acohpsk.Nsymbrowpilot,:)];
 
   if (sync == 4) || (next_sync == 4)  
-    [rx_symb rx_bits amp_ phi_ EsNo_] = qpsk_symbols_to_bits(acohpsk, acohpsk.ct_symb_ff_buf);
+    [rx_symb rx_bits rx_symb_linear amp_ phi_ EsNo_] = qpsk_symbols_to_bits(acohpsk, acohpsk.ct_symb_ff_buf);
     rx_symb_log = [rx_symb_log; rx_symb];
     rx_amp_log = [rx_amp_log; amp_];
     rx_phi_log = [rx_phi_log; phi_];

diff --git a/codec2-dev/octave/test_cohpsk.m b/codec2-dev/octave/test_cohpsk.m
index 7cdc0f13f6950f4cee1414391ae46147a557ca32..bdfced8bc8e4967c557bfe38ccff1714ceed2c70 100644 (file)
--- a/codec2-dev/octave/test_cohpsk.m
+++ b/codec2-dev/octave/test_cohpsk.m
@@ -105,7 +105,7 @@ function test_single
   sim_in.ldpc_code_rate   = 1;
   sim_in.ldpc_code        = 0;
 
-  sim_in.Ntrials          = 35;
+  sim_in.Ntrials          = 500;
   sim_in.Esvec            = 8; 
   sim_in.hf_sim           = 0;
   sim_in.hf_mag_only      = 0;
@@ -570,11 +570,11 @@ endfunction
 
 more off;
 %test_curves();
-%test_single();
+test_single();
 %rate_Fs_tx("tx_zero.raw");
 %rate_Fs_tx("tx.raw");
 %rate_Fs_rx("tx_-4dB.wav")
 %rate_Fs_rx("tx.raw")
 %test_freq_off_est("tx.raw",40,6400)
-gen_test_bits();
+%gen_test_bits();
 

diff --git a/codec2-dev/src/codec2_cohpsk.h b/codec2-dev/src/codec2_cohpsk.h
index 28b2f5245d54268f299d1a0e65fb70ae3d01e848..77b5c220e6a0ae4b80f51021fb34604d0e3310ab 100644 (file)
--- a/codec2-dev/src/codec2_cohpsk.h
+++ b/codec2-dev/src/codec2_cohpsk.h
@@ -31,6 +31,8 @@
 #define COHPSK_BITS_PER_FRAME     32              /* hard coded for now */
 #define COHPSK_NC                  4              /* hard coded for now */
 #define COHPSK_SAMPLES_PER_FRAME 960
+#define COHPSK_RS                 50
+#define COHPSK_FS               8000
 
 #include "comp.h"
 #include "codec2_fdmdv.h"

diff --git a/codec2-dev/src/cohpsk.c b/codec2-dev/src/cohpsk.c
index 4fc754bd0ecfb4a6fd92d3c16817ee91824ec477..9aa07d42a9b9b29a1a50f8b9500ec665219686c2 100644 (file)
--- a/codec2-dev/src/cohpsk.c
+++ b/codec2-dev/src/cohpsk.c
@@ -14,7 +14,7 @@
       [ ] fading channel
       [ ] freq drift
       [ ] timing drift
-  [ ] tune and meas impl loss perf for above
+  [ ] tune perf/impl loss to get closer to ideal
   [ ] freq offset/drift feedback loop 
   [ ] smaller freq est block size to min ram req
                                                       
@@ -95,6 +95,8 @@ struct COHPSK *cohpsk_create(void)
     float          freq_hz;
 
     assert(COHPSK_SAMPLES_PER_FRAME == M*NSYMROWPILOT);
+    assert(COHPSK_RS == RS);
+    assert(COHPSK_FS == FS);
 
     coh = (struct COHPSK*)malloc(sizeof(struct COHPSK));
     if (coh == NULL)
@@ -331,7 +333,7 @@ void coarse_freq_offset_est(struct COHPSK *coh, struct FDMDV *fdmdv, COMP ch_fdm
         bin_est = num/den;
         coh->f_est = floor(bin_est/sc+0.5);
 
-        fprintf(stderr, "coarse freq est: %f\n", coh->f_est);
+        fprintf(stderr, "  coarse freq est: %f\n", coh->f_est);
         
         *next_sync = 1;
     }
@@ -422,7 +424,7 @@ void frame_sync_fine_freq_est(struct COHPSK *coh, COMP ch_symb[][PILOTS_NC], int
         fprintf(stderr, "  fine freq f: %f max_corr: %f max_mag: %f ct: %d\n", coh->f_fine_est, max_corr, max_mag, coh->ct);
  
         if (max_corr/max_mag > 0.9) {
-            fprintf(stderr, "in sync!\n");
+            fprintf(stderr, "  in sync!\n");
             *next_sync = 4;
             coh->sync_timer = 0;
         }

diff --git a/codec2-dev/unittest/test_cohpsk_ch.c b/codec2-dev/unittest/test_cohpsk_ch.c
index 8b850a08624beb53a9537873c327e3771772aa21..bed611a23d50d4329c0e8562b3467e5802e02dc9 100644 (file)
--- a/codec2-dev/unittest/test_cohpsk_ch.c
+++ b/codec2-dev/unittest/test_cohpsk_ch.c
@@ -38,8 +38,9 @@
 #include "comp_prim.h"
 #include "noise_samples.h"
 
-#define FRAMES 350
-#define FOFFHZ 10.5
+#define FRAMES   350
+#define FOFF_HZ  10.5
+#define ES_NO_DB  12.0
 
 int main(int argc, char *argv[])
 {
@@ -55,6 +56,17 @@ int main(int argc, char *argv[])
     int            noise_r, noise_end;
     float          corr;
     int            state, next_state, nerrors, nbits, reliable_sync_bit;
+    float          EsNo, variance;
+    COMP           scaled_noise;
+    float          EsNodB, foff_hz;
+
+    EsNodB = ES_NO_DB;
+    foff_hz =  FOFF_HZ;
+    if (argc == 3) {
+        EsNodB = atof(argv[1]);
+        foff_hz = atof(argv[2]);
+    }
+    fprintf(stderr, "EsNodB: %4.2f foff: %4.2f Hz\n", EsNodB, foff_hz);
 
     coh = cohpsk_create();
     assert(coh != NULL);
@@ -65,6 +77,13 @@ int main(int argc, char *argv[])
     noise_r = 0; 
     noise_end = sizeof(noise)/sizeof(COMP);
     
+    /*  each carrier has power = 2, total power 2Nc, total symbol rate
+        NcRs, noise BW B=Fs Es/No = (C/Rs)/(N/B), N = var =
+        2NcFs/NcRs(Es/No) = 2Fs/Rs(Es/No) */
+
+    EsNo = pow(10.0, EsNodB/10.0);
+    variance = 2.0*COHPSK_FS/(COHPSK_RS*EsNo);
+
     /* Main Loop ---------------------------------------------------------------------*/
 
     for(f=0; f<FRAMES; f++) {
@@ -85,14 +104,15 @@ int main(int argc, char *argv[])
                                  Channel
        \*---------------------------------------------------------*/
 
-        fdmdv_freq_shift(ch_fdm, tx_fdm, FOFFHZ, &phase_ch, COHPSK_SAMPLES_PER_FRAME);
+        fdmdv_freq_shift(ch_fdm, tx_fdm, foff_hz, &phase_ch, COHPSK_SAMPLES_PER_FRAME);
 
         for(r=0; r<COHPSK_SAMPLES_PER_FRAME; r++) {
-           ch_fdm[r] = cadd(ch_fdm[r], noise[noise_r]);
-           noise_r++;
-           if (noise_r > noise_end)
-               noise_r = 0;
-         }
+            scaled_noise = fcmult(sqrt(variance), noise[noise_r]);
+            ch_fdm[r] = cadd(ch_fdm[r], scaled_noise);
+            noise_r++;
+            if (noise_r > noise_end)
+                noise_r = 0;
+        }
 
        /* --------------------------------------------------------*\
                                  Demod
@@ -105,17 +125,18 @@ int main(int argc, char *argv[])
             corr += (1.0 - 2.0*(rx_bits[i] & 0x1)) * (1.0 - 2.0*ptest_bits_coh_rx[i]);
         }
 
-        /* state logic to sybc up to test data */
+        /* state logic to sync up to test data */
 
         next_state = state;
 
         if (state == 0) {
-            fprintf(stderr, "corr %f\n", corr);            
             if (reliable_sync_bit && (corr == COHPSK_BITS_PER_FRAME)) {
                 next_state = 1;
                 ptest_bits_coh_rx += COHPSK_BITS_PER_FRAME;
                 nerrors = COHPSK_BITS_PER_FRAME - corr;
                 nbits = COHPSK_BITS_PER_FRAME;
+                fprintf(stderr, "  test data sync\n");            
+
             }
         }
 
@@ -131,7 +152,7 @@ int main(int argc, char *argv[])
         state = next_state;
     }
     
-    printf("BER: %3.2f Nbits: %d Nerrors: %d\n", (float)nerrors/nbits, nbits, nerrors);
+    printf("%4.3f %d %d\n", (float)nerrors/nbits, nbits, nerrors);
 
     cohpsk_destroy(coh);