From 0033da561101f7d83d5bf564972b2c8060288cda Mon Sep 17 00:00:00 2001
From: Romain Beurdouche <romain.beurdouche@eurecom.fr>
Date: Fri, 14 Mar 2025 15:04:55 +0000
Subject: [PATCH] fix(nr_ulschsim): make nr_ulschsim functional

There was two issues that were making nr_ulschsim non functional:
1. The channel output was not copied to decoder input (llr array)
2. The test on decoding successful outcome was wrong

The result was that nr_ulschsim was succesfull whatever were its arguments.
This commit fixes the two issues so that nr_ulschsim is now functional.
---
 openair1/SIMULATION/NR_PHY/ulschsim.c | 30 ++++++++++++++++-----------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/openair1/SIMULATION/NR_PHY/ulschsim.c b/openair1/SIMULATION/NR_PHY/ulschsim.c
index 3027ceff58..6e157ac57e 100644
--- a/openair1/SIMULATION/NR_PHY/ulschsim.c
+++ b/openair1/SIMULATION/NR_PHY/ulschsim.c
@@ -448,6 +448,7 @@ int main(int argc, char **argv)
   NR_gNB_ULSCH_t *ulsch_gNB = &gNB->ulsch[UE_id];
   NR_UL_gNB_HARQ_t *harq_process_gNB = ulsch_gNB->harq_process;
   nfapi_nr_pusch_pdu_t *rel15_ul = &harq_process_gNB->ulsch_pdu;
+  NR_gNB_PUSCH *pusch_vars = &gNB->pusch_vars[UE_id];
 
   nr_phy_data_tx_t phy_data = {0};
   NR_UE_ULSCH_t *ulsch_ue = &phy_data.ulsch;
@@ -475,7 +476,6 @@ int main(int argc, char **argv)
   ///////////////////////////////////////////////////
 
   double modulated_input[16 * 68 * 384]; // [hna] 16 segments, 68*Zc
-  short channel_output_fixed[16 * 68 * 384];
   short channel_output_uncoded[16 * 68 * 384];
   unsigned int errors_bit_uncoded = 0;
 
@@ -526,12 +526,13 @@ int main(int argc, char **argv)
   ////////////////////////////////////////////////////////////////////
 
   for (SNR = snr0; SNR < snr1 && !stop; SNR += snr_step) {
+    errors_bit_uncoded = 0;
     n_errors = 0;
     n_false_positive = 0;
 
     for (trial = 0; trial < n_trials && !stop; trial++) {
-
-      errors_bit_uncoded = 0;
+      memset(pusch_vars->llr, 0, (8 * ((3 * 8 * 6144) + 12)) * sizeof(int16_t));
+      harq_process_gNB->harq_to_be_cleared = true;
 
       for (i = 0; i < available_bits; i++) {
 
@@ -555,16 +556,16 @@ int main(int argc, char **argv)
 #if 1
         SNR_lin = pow(10, SNR / 10.0);
         sigma = 1.0 / sqrt(2 * SNR_lin);
-        channel_output_fixed[i] = (short) quantize(sigma / 4.0 / 4.0,
-                                                   modulated_input[i] + sigma * gaussdouble(0.0, 1.0),
-                                                   qbits);
+        pusch_vars->llr[i] = (int16_t) quantize(sigma / 4.0 / 4.0,
+                                                modulated_input[i] + sigma * gaussdouble(0.0, 1.0),
+                                                qbits);
 #else
-        channel_output_fixed[i] = (short) quantize(0.01, modulated_input[i], qbits);
+        pusch_vars->llr[i] = (int16_t) quantize(0.01, modulated_input[i], qbits);
 #endif
-        //printf("channel_output_fixed[%d]: %d\n",i,channel_output_fixed[i]);
+        //printf("pusch_vars->llr[%d]: %d\n", i, pusch_vars->llr[i]);
 
         //Uncoded BER
-        if (channel_output_fixed[i] < 0)
+        if (pusch_vars->llr[i] < 0)
           channel_output_uncoded[i] = 1;  //QPSK demod
         else
           channel_output_uncoded[i] = 0;
@@ -581,14 +582,19 @@ int main(int argc, char **argv)
       exit(-1);
 #endif
       nr_ulsch_decoding(gNB, frame_parms, frame, subframe, &G, &UE_id, 1);
-      bool crc_valid = check_crc(harq_process_gNB->b, lenWithCrc(1, (harq_process_gNB->TBS) << 3), crcType(1, (harq_process_gNB->TBS) << 3));
-      if (!crc_valid) {
+      if (harq_process_gNB->processedSegments == harq_process_gNB->C) {
+        bool crc_valid = check_crc(harq_process_gNB->b, lenWithCrc(1, (harq_process_gNB->TBS) << 3), crcType(1, (harq_process_gNB->TBS) << 3));
+        if (!crc_valid) {
+          n_false_positive++;
+        }
+      } else {
         n_errors++;
       }
     }
 
     printf("*****************************************\n");
-    printf("SNR %f, BLER %f (false positive %f)\n", SNR,
+    printf("SNR %f, uncoded BER %f, BLER %f (false positive %f)\n", SNR,
+           (float) errors_bit_uncoded / (float) available_bits / (float) n_trials,
            (float) n_errors / (float) n_trials,
            (float) n_false_positive / (float) n_trials);
     printf("*****************************************\n");