uncoded BER 0 with ofdm_mod/ofdm_demod, LDPC decode not working yet

9 files changed, 66 insertions, 61 deletions

diff --git a/src/freedv_2020.c b/src/freedv_2020.c
index 4a54b5b..9963819 100644
--- a/src/freedv_2020.c
+++ b/src/freedv_2020.c
@@ -248,7 +248,7 @@ int freedv_comprx_2020(struct freedv *f, COMP demod_in[]) {
 
     ofdm_demod(ofdm, rx_bits, demod_in);
     ofdm_extract_uw(ofdm, ofdm->rx_np, ofdm->rx_amp, rx_uw);
-    ofdm_disassemble_qpsk_modem_packet_with_text_amps(
+    ofdm_disassemble_psk_modem_packet_with_text_amps(
         ofdm, ofdm->rx_np, ofdm->rx_amp, payload_syms, payload_amps, txt_bits,
         &txt_sym_index);
 
@@ -279,8 +279,8 @@ int freedv_comprx_2020(struct freedv *f, COMP demod_in[]) {
     uint8_t out_char[coded_bits_per_frame];
 
     if (f->test_frames) {
-      Nerrs_raw =
-          count_uncoded_errors(ldpc, &f->ofdm->config, codeword_symbols_de, 0);
+      Nerrs_raw = count_uncoded_errors(ldpc, &f->ofdm->config,
+                                       codeword_symbols_de, payload_amps_de, 0);
       f->total_bit_errors += Nerrs_raw;
       f->total_bits += f->ofdm_bitsperframe;
     }
diff --git a/src/freedv_700.c b/src/freedv_700.c
index 8ab0cbb..257b80f 100644
--- a/src/freedv_700.c
+++ b/src/freedv_700.c
@@ -490,7 +490,7 @@ int freedv_comp_short_rx_ofdm(struct freedv *f, void *demod_in_8kHz,
       /* we have received enough modem frames to complete packet and run LDPC
        * decoder */
       int txt_sym_index = 0;
-      ofdm_disassemble_qpsk_modem_packet_with_text_amps(
+      ofdm_disassemble_psk_modem_packet_with_text_amps(
           ofdm, rx_syms, rx_amps, payload_syms, payload_amps, txt_bits,
           &txt_sym_index);
 
@@ -526,8 +526,9 @@ int freedv_comp_short_rx_ofdm(struct freedv *f, void *demod_in_8kHz,
 
       if (f->test_frames) {
         /* est uncoded BER from payload bits */
-        Nerrs_raw = count_uncoded_errors(
-            ldpc, &f->ofdm->config, payload_syms_de, strlen(ofdm->data_mode));
+        Nerrs_raw =
+            count_uncoded_errors(ldpc, &f->ofdm->config, payload_syms_de,
+                                 payload_amps_de, strlen(ofdm->data_mode));
         f->total_bit_errors += Nerrs_raw;
         f->total_bits += Npayloadbitsperpacket;
 
diff --git a/src/interldpc.c b/src/interldpc.c
index 8cec647..cb6f964 100644
--- a/src/interldpc.c
+++ b/src/interldpc.c
@@ -134,17 +134,18 @@ void ldpc_encode_frame(struct LDPC *ldpc, int codeword[],
   for (j = 0; j < ldpc->NumberParityBits; i++, j++) codeword[i] = pbits[j];
 }
 
-void qpsk_modulate_frame(COMP tx_symbols[], int codeword[], int n) {
+void psk_modulate_frame(int bps, COMP tx_symbols[], int codeword[], int n) {
   int s, i;
-  int dibit[2];
-  complex float qpsk_symb;
-
-  for (s = 0, i = 0; i < n; s += 2, i++) {
-    dibit[0] = codeword[s + 1] & 0x1;
-    dibit[1] = codeword[s] & 0x1;
-    qpsk_symb = qpsk_mod(dibit);
-    tx_symbols[i].real = crealf(qpsk_symb);
-    tx_symbols[i].imag = cimagf(qpsk_symb);
+  int bits[bps];
+  complex float symb;
+
+  assert((bps == 2) || (bps == 4));
+  for (s = 0, i = 0; i < n; s += bps, i++) {
+    for (int b = 0; b < bps; b++) bits[b] = codeword[s + bps - 1 - b] & 0x1;
+    if (bps == 2) symb = qpsk_mod(bits);
+    if (bps == 4) symb = qam16_mod(bits);
+    tx_symbols[i].real = crealf(symb);
+    tx_symbols[i].imag = cimagf(symb);
   }
 }
 
@@ -220,7 +221,8 @@ void ldpc_decode_frame(struct LDPC *ldpc, int *parityCheckCount, int *iter,
    of txt bits as this is done after we dissassemmble the frame */
 
 int count_uncoded_errors(struct LDPC *ldpc, struct OFDM_CONFIG *config,
-                         COMP codeword_symbols_de[], int crc16) {
+                         COMP codeword_symbols_de[], float codeword_amps_de[],
+                         int crc16) {
   int i, Nerrs;
 
   int coded_syms_per_frame = ldpc->coded_bits_per_frame / config->bps;
@@ -248,12 +250,13 @@ int count_uncoded_errors(struct LDPC *ldpc, struct OFDM_CONFIG *config,
   ldpc_encode_frame(ldpc, test_codeword, tx_bits);
 
   for (i = 0; i < coded_syms_per_frame; i++) {
-    int bits[2];
+    int bits[config->bps];
     complex float s =
         codeword_symbols_de[i].real + I * codeword_symbols_de[i].imag;
-    qpsk_demod(s, bits);
-    rx_bits_raw[config->bps * i] = bits[1];
-    rx_bits_raw[config->bps * i + 1] = bits[0];
+    if (config->bps == 2) qpsk_demod(s, bits);
+    if (config->bps == 4) qam16_demod(s, bits, codeword_amps_de[i]);
+    for (int b = 0; b < config->bps; b++)
+      rx_bits_raw[config->bps * i + b] = bits[config->bps - 1 - b];
   }
 
   Nerrs = 0;
@@ -329,10 +332,11 @@ void ofdm_ldpc_interleave_tx(struct OFDM *ofdm, struct LDPC *ldpc,
   complex float tx_symbols[Nbitsperpacket / ofdm->bps];
 
   ldpc_encode_frame(ldpc, codeword, tx_bits);
-  qpsk_modulate_frame(payload_symbols, codeword, Npayloadsymsperpacket);
+  psk_modulate_frame(ofdm->bps, payload_symbols, codeword,
+                     Npayloadsymsperpacket);
   gp_interleave_comp(payload_symbols_inter, payload_symbols,
                      Npayloadsymsperpacket);
-  ofdm_assemble_qpsk_modem_packet_symbols(ofdm, tx_symbols,
-                                          payload_symbols_inter, txt_bits);
+  ofdm_assemble_psk_modem_packet_symbols(ofdm, tx_symbols,
+                                         payload_symbols_inter, txt_bits);
   ofdm_txframe(ofdm, tx_sams, tx_symbols);
 }
diff --git a/src/interldpc.h b/src/interldpc.h
index 3b1d1ca..1c72558 100644
--- a/src/interldpc.h
+++ b/src/interldpc.h
@@ -49,7 +49,8 @@ void qpsk_modulate_frame(COMP tx_symbols[], int codeword[], int n);
 void ldpc_decode_frame(struct LDPC *ldpc, int *parityCheckCount, int *iter,
                        uint8_t out_char[], float llr[]);
 int count_uncoded_errors(struct LDPC *ldpc, struct OFDM_CONFIG *config,
-                         COMP codeword_symbols_de[], int crc16);
+                         COMP codeword_symbols_de[], float codeword_amps_de[],
+                         int crc16);
 int count_errors(uint8_t tx_bits[], uint8_t rx_bits[], int n);
 void count_errors_protection_mode(int protection_mode, int *pNerrs,
                                   int *pNcoded, uint8_t tx_bits[],
diff --git a/src/ofdm.c b/src/ofdm.c
index c5debf5..bb9a10f 100644
--- a/src/ofdm.c
+++ b/src/ofdm.c
@@ -2381,9 +2381,9 @@ void ofdm_get_demod_stats(struct OFDM *ofdm, struct MODEM_STATS *stats,
 /*
  * Assemble packet of bits from UW, payload bits, and txt bits
  */
-void ofdm_assemble_qpsk_modem_packet(struct OFDM *ofdm, uint8_t modem_frame[],
-                                     uint8_t payload_bits[],
-                                     uint8_t txt_bits[]) {
+void ofdm_assemble_psk_modem_packet(struct OFDM *ofdm, uint8_t modem_frame[],
+                                    uint8_t payload_bits[],
+                                    uint8_t txt_bits[]) {
   int s, t;
 
   int p = 0;
@@ -2410,10 +2410,10 @@ void ofdm_assemble_qpsk_modem_packet(struct OFDM *ofdm, uint8_t modem_frame[],
 /*
  * Assemble packet of symbols from UW, payload symbols, and txt bits
  */
-void ofdm_assemble_qpsk_modem_packet_symbols(struct OFDM *ofdm,
-                                             complex float modem_packet[],
-                                             COMP payload_syms[],
-                                             uint8_t txt_bits[]) {
+void ofdm_assemble_psk_modem_packet_symbols(struct OFDM *ofdm,
+                                            complex float modem_packet[],
+                                            COMP payload_syms[],
+                                            uint8_t txt_bits[]) {
   complex float *payload =
       (complex float *)&payload_syms[0];  // complex has same memory layout
   int Nsymsperpacket = ofdm->bitsperpacket / ofdm->bps;
@@ -2436,7 +2436,8 @@ void ofdm_assemble_qpsk_modem_packet_symbols(struct OFDM *ofdm,
   assert(u == Nuwsyms);
   assert(p == (Nsymsperpacket - Nuwsyms - Ntxtsyms));
 
-  /* txt bit insertion only works for QPSK at this stage */
+  /* txt bit insertion only works for QPSK at this stage, however QAM modes
+   * generally has no txt bits  */
   assert((Ntxtsyms == 0) || (ofdm->bps == 2));
   for (t = 0; s < Nsymsperpacket; s++, t += 2) {
     dibit[1] = txt_bits[t] & 0x1;
@@ -2451,11 +2452,11 @@ void ofdm_assemble_qpsk_modem_packet_symbols(struct OFDM *ofdm,
  * Disassemble a received packet of symbols into UW bits and payload data
  * symbols
  */
-void ofdm_disassemble_qpsk_modem_packet(struct OFDM *ofdm,
-                                        complex float rx_syms[],
-                                        float rx_amps[], COMP codeword_syms[],
-                                        float codeword_amps[],
-                                        short txt_bits[]) {
+void ofdm_disassemble_psk_modem_packet(struct OFDM *ofdm,
+                                       complex float rx_syms[], float rx_amps[],
+                                       COMP codeword_syms[],
+                                       float codeword_amps[],
+                                       short txt_bits[]) {
   complex float *codeword =
       (complex float *)&codeword_syms[0];  // complex has same memory layout
   int Nsymsperpacket = ofdm->bitsperpacket / ofdm->bps;
@@ -2495,7 +2496,7 @@ void ofdm_disassemble_qpsk_modem_packet(struct OFDM *ofdm,
  * Disassemble a received packet of symbols into UW bits and payload data
  * symbols
  */
-void ofdm_disassemble_qpsk_modem_packet_with_text_amps(
+void ofdm_disassemble_psk_modem_packet_with_text_amps(
     struct OFDM *ofdm, complex float rx_syms[], float rx_amps[],
     COMP codeword_syms[], float codeword_amps[], short txt_bits[],
     int *textIndex) {
diff --git a/src/ofdm_demod.c b/src/ofdm_demod.c
index 0f3d802..f8dc7a5 100644
--- a/src/ofdm_demod.c
+++ b/src/ofdm_demod.c
@@ -473,8 +473,8 @@ int main(int argc, char *argv[]) {
         /* we have received enough frames to make a complete packet .... */
 
         /* extract payload symbols from packet */
-        ofdm_disassemble_qpsk_modem_packet(ofdm, rx_syms, rx_amps, payload_syms,
-                                           payload_amps, txt_bits);
+        ofdm_disassemble_psk_modem_packet(ofdm, rx_syms, rx_amps, payload_syms,
+                                          payload_amps, txt_bits);
 
         if (ldpc_en) {
           assert((ofdm_nuwbits + ofdm_ntxtbits + Npayloadbitsperpacket) <=
@@ -492,8 +492,8 @@ int main(int argc, char *argv[]) {
           uint8_t out_char[Npayloadbitsperpacket];
 
           if (testframes == true) {
-            Nerrs_raw =
-                count_uncoded_errors(&ldpc, ofdm_config, payload_syms_de, 0);
+            Nerrs_raw = count_uncoded_errors(
+                &ldpc, ofdm_config, payload_syms_de, payload_amps_de, 0);
             Terrs += Nerrs_raw;
             Tbits +=
                 Npayloadbitsperpacket; /* not counting errors in txt bits */
@@ -524,7 +524,7 @@ int main(int argc, char *argv[]) {
           assert(Npayloadsymsperpacket * ofdm_config->bps ==
                  Npayloadbitsperpacket);
           for (i = 0; i < Npayloadsymsperpacket; i++) {
-            int bits[2];
+            int bits[ofdm->bps];
             complex float s = payload_syms[i].real + I * payload_syms[i].imag;
             qpsk_demod(s, bits);
             rx_bits_char[ofdm_config->bps * i] = bits[1];
@@ -547,8 +547,7 @@ int main(int argc, char *argv[]) {
           memset(txt_bits, 0, ofdm_ntxtbits);
           uint8_t tx_bits[Nbitsperpacket];
           ofdm_generate_payload_data_bits(payload_bits, Npayloadbitsperpacket);
-          ofdm_assemble_qpsk_modem_packet(ofdm, tx_bits, payload_bits,
-                                          txt_bits);
+          ofdm_assemble_psk_modem_packet(ofdm, tx_bits, payload_bits, txt_bits);
 
           /* count errors across UW, payload, txt bits */
           int rx_bits[Nbitsperpacket];
diff --git a/src/ofdm_internal.h b/src/ofdm_internal.h
index b57451a..af449d3 100644
--- a/src/ofdm_internal.h
+++ b/src/ofdm_internal.h
@@ -260,17 +260,17 @@ complex float qam16_mod(int *);
 void qpsk_demod(complex float, int *);
 void qam16_demod(complex float, int *, float);
 void ofdm_txframe(struct OFDM *, complex float *, complex float[]);
-void ofdm_assemble_qpsk_modem_packet(struct OFDM *, uint8_t[], uint8_t[],
-                                     uint8_t[]);
-void ofdm_assemble_qpsk_modem_packet_symbols(struct OFDM *, complex float[],
-                                             COMP[], uint8_t[]);
-void ofdm_disassemble_qpsk_modem_packet(struct OFDM *, complex float rx_syms[],
-                                        float rx_amps[], COMP[], float[],
-                                        short[]);
-void ofdm_disassemble_qpsk_modem_packet_with_text_amps(struct OFDM *,
-                                                       complex float rx_syms[],
-                                                       float rx_amps[], COMP[],
-                                                       float[], short[], int *);
+void ofdm_assemble_psk_modem_packet(struct OFDM *, uint8_t[], uint8_t[],
+                                    uint8_t[]);
+void ofdm_assemble_psk_modem_packet_symbols(struct OFDM *, complex float[],
+                                            COMP[], uint8_t[]);
+void ofdm_disassemble_psk_modem_packet(struct OFDM *, complex float rx_syms[],
+                                       float rx_amps[], COMP[], float[],
+                                       short[]);
+void ofdm_disassemble_psk_modem_packet_with_text_amps(struct OFDM *,
+                                                      complex float rx_syms[],
+                                                      float rx_amps[], COMP[],
+                                                      float[], short[], int *);
 void ofdm_extract_uw(struct OFDM *ofdm, complex float rx_syms[],
                      float rx_amps[], uint8_t rx_uw[]);
 void ofdm_rand(uint16_t[], int);
diff --git a/src/ofdm_mod.c b/src/ofdm_mod.c
index d4c495e..23444f5 100644
--- a/src/ofdm_mod.c
+++ b/src/ofdm_mod.c
@@ -398,8 +398,7 @@ int main(int argc, char *argv[]) {
 
         /* assemble packet of bits then modulate */
         uint8_t tx_bits_char[Nbitsperpacket];
-        ofdm_assemble_qpsk_modem_packet(ofdm, tx_bits_char, data_bits,
-                                        txt_bits);
+        ofdm_assemble_psk_modem_packet(ofdm, tx_bits_char, data_bits, txt_bits);
         int tx_bits[Nbitsperpacket];
         for (i = 0; i < Nbitsperpacket; i++) tx_bits[i] = tx_bits_char[i];
         COMP tx_sams[Nsamperpacket];
diff --git a/unittest/tofdm.c b/unittest/tofdm.c
index b4d60b7..0efcc60 100644
--- a/unittest/tofdm.c
+++ b/unittest/tofdm.c
@@ -324,8 +324,8 @@ int main(int argc, char *argv[]) {
       for (i = 0; i < ofdm_ntxtbits; i++) txt_bits[i] = 0;
 
       uint8_t tx_bits_char[ofdm_bitsperframe];
-      ofdm_assemble_qpsk_modem_packet(ofdm, tx_bits_char, payload_bits,
-                                      txt_bits);
+      ofdm_assemble_psk_modem_packet(ofdm, tx_bits_char, payload_bits,
+                                     txt_bits);
       for (i = 0; i < ofdm_bitsperframe; i++) tx_bits[i] = tx_bits_char[i];
     }