Change LDPC decoder rate based on round/rv

openair1/PHY/CODING/coding_defs.h

@@ -472,6 +472,13 @@ void nr_interleaving_ldpc(uint32_t E, uint8_t Qm, uint8_t *e,uint8_t *f);
 
 void nr_deinterleaving_ldpc(uint32_t E, uint8_t Qm, int16_t *e,int16_t *f);
 
+int nr_get_R_ldpc_decoder(int rvidx,
+                          int E,
+                          int BG,
+                          int Z,
+                          int *llrLen,
+                          int round);
+
 int nr_rate_matching_ldpc(uint32_t Tbslbrm,
                           uint8_t BG,
                           uint16_t Z,

openair1/PHY/CODING/nr_rate_matching.c

@@ -386,6 +386,39 @@ void nr_deinterleaving_ldpc(uint32_t E, uint8_t Qm, int16_t *e,int16_t *f)
 
 }
 
+int nr_get_R_ldpc_decoder(int rvidx,
+                          int E,
+                          int BG,
+                          int Z,
+                          int *llrLen,
+                          int round) {
+  AssertFatal(BG == 1 || BG == 2, "Unknown BG %d\n", BG);
+
+  int Ncb = (BG==1)?(66*Z):(50*Z);
+  int infoBits = (index_k0[BG-1][rvidx] * Z + E);
+
+  if (round == 0) *llrLen = infoBits;
+  if (infoBits > Ncb) infoBits = Ncb;
+  if (infoBits > *llrLen) *llrLen = infoBits;
+
+  int sysBits = (BG==1)?(22*Z):(10*Z);
+  float decoderR = (float)sysBits/(infoBits + 2*Z);
+
+  if (BG == 2)
+    if (decoderR < 0.3333)
+      return 15;
+    else if (decoderR < 0.6667)
+      return 13;
+    else
+      return 23;
+  else
+    if (decoderR < 0.6667)
+      return 13;
+    else if (decoderR < 0.8889)
+      return 23;
+    else
+      return 89;
+}
 
 int nr_rate_matching_ldpc(uint32_t Tbslbrm,
                           uint8_t BG,

openair1/PHY/NR_TRANSPORT/nr_ulsch_decoding.c

@@ -234,6 +234,12 @@ void nr_processULSegment(void* arg) {
   short* ulsch_llr = rdata->ulsch_llr;
   int max_ldpc_iterations = p_decoderParms->numMaxIter;
   int8_t llrProcBuf[OAI_UL_LDPC_MAX_NUM_LLR] __attribute__ ((aligned(32)));
+  p_decoderParms->R = nr_get_R_ldpc_decoder(rv_index,
+                                            E,
+                                            p_decoderParms->BG,
+                                            p_decoderParms->Z,
+                                            &ulsch_harq->llrLen,
+                                            ulsch_harq->round);
 
   int16_t  z [68*384 + 16] __attribute__ ((aligned(16)));
   int8_t   l [68*384 + 16] __attribute__ ((aligned(16)));

openair1/PHY/NR_UE_TRANSPORT/nr_dlsch_decoding.c

@@ -251,6 +251,12 @@ void nr_processDLSegment(void* arg) {
   short* dlsch_llr = rdata->dlsch_llr;
   rdata->decodeIterations = dlsch->max_ldpc_iterations + 1;
   int8_t llrProcBuf[OAI_UL_LDPC_MAX_NUM_LLR] __attribute__ ((aligned(32)));
+  p_decoderParms->R = nr_get_R_ldpc_decoder(rdata->rv_index,
+                                            E,
+                                            p_decoderParms->BG,
+                                            p_decoderParms->Z,
+                                            &harq_process->llrLen,
+                                            harq_process->DLround);
 
   int16_t  z [68*384 + 16] __attribute__ ((aligned(16)));
   int8_t   l [68*384 + 16] __attribute__ ((aligned(16)));

openair1/PHY/NR_UE_TRANSPORT/nr_transport_ue.h

@@ -259,6 +259,9 @@ typedef struct {
   uint16_t dlDmrsScramblingId;
   /// PDU BITMAP 
   uint16_t pduBitmap;
+  /// Last index of LLR buffer that contains information.
+  /// Used for computing LDPC decoder R
+  int llrLen;
 } NR_DL_UE_HARQ_t;
 
 typedef struct {

openair1/PHY/defs_gNB.h

@@ -336,6 +336,9 @@ typedef struct {
   int16_t q_RI[MAX_RI_PAYLOAD];
   /// Temporary h sequence to flag PUSCH_x/PUSCH_y symbols which are not scrambled
   uint8_t h[MAX_NUM_CHANNEL_BITS];
+  /// Last index of LLR buffer that contains information.
+  /// Used for computing LDPC decoder R
+  int llrLen;
   //////////////////////////////////////////////////////////////
 } NR_UL_gNB_HARQ_t;