fix(nrLDPC_decoder): Cleaning LDPC iteration accounting in NR

The idea is to make LDPC iteration accounting more standard from a C coding perspective by making two changes:
1. Now the iteration counter starts at 0 for the first iteration and goes up to max_ldpc_iterations - 1 for the last iteration.
   If it is equal to max_ldpc_iterations, it means that decoding failed.
2. A chain of useless returns in the UE DLSCH decoding call chain was removed.

openair1/SIMULATION/NR_PHY/dlschsim.c

@@ -123,7 +123,6 @@ int main(int argc, char **argv)
   NR_DL_FRAME_PARMS *frame_parms;
   double sigma;
   unsigned char qbits = 8;
-  int ret;
   int loglvl = OAILOG_WARNING;
   uint8_t dlsch_threads = 0;
   float target_error_rate = 0.01;
@@ -577,18 +576,18 @@ int main(int argc, char **argv)
       short *p_channel_output_fixed = channel_output_fixed;
       uint8_t *p_b = b;
       int available_bits_array[1] = { available_bits };
-      ret = nr_dlsch_decoding(UE,
-                              &proc,
-                              dlsch0_ue,
-                              &p_channel_output_fixed,
-                              &p_b,
-                              available_bits_array,
-                              1,
-                              DLSCH_ids);
+      nr_dlsch_decoding(UE,
+                        &proc,
+                        dlsch0_ue,
+                        &p_channel_output_fixed,
+                        &p_b,
+                        available_bits_array,
+                        1,
+                        DLSCH_ids);
 
       vcd_signal_dumper_dump_function_by_name(VCD_SIGNAL_DUMPER_FUNCTIONS_DLSCH_DECODING0, VCD_FUNCTION_OUT);
 
-      if (ret > dlsch0_ue->max_ldpc_iterations)
+      if (dlsch0_ue->last_iteration_cnt > dlsch0_ue->max_ldpc_iterations)
 				n_errors++;
 
 			//count errors

openair1/SIMULATION/NR_PHY/dlsim.c

@@ -1163,7 +1163,7 @@ printf("%d\n", slot);
         //---------------------- count errors ----------------------
         //----------------------------------------------------------
 
-        if (dlsch0->last_iteration_cnt >= dlsch0->max_ldpc_iterations+1)
+        if (dlsch0->last_iteration_cnt >= dlsch0->max_ldpc_iterations)
           n_errors[round]++;
 
         int16_t *UE_llr = (int16_t*)UE->phy_sim_pdsch_llr;

openair1/SIMULATION/NR_PHY/ulsim.c

@@ -1420,7 +1420,7 @@ int main(int argc, char *argv[])
                 0);
         }
 
-        if ((ulsch_gNB->last_iteration_cnt >= ulsch_gNB->max_ldpc_iterations + 1) || ul_proc_error == 1) {
+        if ((ulsch_gNB->last_iteration_cnt >= ulsch_gNB->max_ldpc_iterations) || ul_proc_error == 1) {
           error_flag = 1;
           n_errors[round]++;
           crc_status = 1;