Fixed number of codewords in format2

srslte/include/srslte/phch/ra.h

@@ -106,6 +106,7 @@ typedef struct SRSLTE_API {
   uint32_t Qm2; 
   srslte_ra_mcs_t mcs;
   srslte_ra_mcs_t mcs2;
+  uint32_t nof_tb;
 } srslte_ra_dl_grant_t;
 
 /** Unpacked DCI message for DL grant */
@@ -134,7 +135,7 @@ typedef struct SRSLTE_API {
   
   uint8_t tpc_pucch;
 
-  uint32_t nof_tb; 
+  bool     tb_en[2]; 
   
   bool     dci_is_1a;
   bool     dci_is_1c; 

srslte/lib/phch/dci.c

@@ -625,7 +625,8 @@ int dci_format1_unpack(srslte_dci_msg_t *msg, srslte_ra_dl_dci_t *data, uint32_t
   
   // TPC not implemented
   
-  data->nof_tb = 1; 
+  data->tb_en[0] = true;
+  data->tb_en[1] = false;
 
   return SRSLTE_SUCCESS;
 }
@@ -814,7 +815,8 @@ int dci_format1As_unpack(srslte_dci_msg_t *msg, srslte_ra_dl_dci_t *data, uint32
     data->type2_alloc.n_prb1a = *y++; // LSB indicates N_prb_1a for TBS
   }
   
-  data->nof_tb = 1; 
+  data->tb_en[0] = true;
+  data->tb_en[1] = false;
 
   return SRSLTE_SUCCESS;
 }
@@ -860,7 +862,8 @@ int dci_format1B_unpack(srslte_dci_msg_t *msg, srslte_ra_dl_dci_t *data, uint32_
   data->pinfo = srslte_bit_pack(&y, tpmi_bits(nof_ports));
   data->pconf = *y++ ? true : false;
 
-  data->nof_tb = 1;   
+  data->tb_en[0] = true;
+  data->tb_en[1] = false;
 
   return SRSLTE_SUCCESS;
 }
@@ -955,7 +958,8 @@ int dci_format1Cs_unpack(srslte_dci_msg_t *msg, srslte_ra_dl_dci_t *data, uint32
   
   msg->nof_bits = (y - msg->data);
   
-  data->nof_tb = 1; 
+  data->tb_en[0] = true;
+  data->tb_en[1] = false;
 
   return SRSLTE_SUCCESS;
 }
@@ -1001,7 +1005,8 @@ int dci_format1D_unpack(srslte_dci_msg_t *msg, srslte_ra_dl_dci_t *data, uint32_
   data->pinfo = srslte_bit_pack(&y, tpmi_bits(nof_ports));
   data->power_offset = *y++ ? true : false;
   
-  data->nof_tb = 1; 
+  data->tb_en[0] = true;
+  data->tb_en[1] = false;
 
   return SRSLTE_SUCCESS;
 }
@@ -1051,16 +1056,23 @@ int dci_format2AB_unpack(srslte_dci_msg_t *msg, srslte_ra_dl_dci_t *data, uint32
   
   /* unpack MCS according to 7.1.7 of 36.213 */
   data->mcs_idx = srslte_bit_pack(&y, 5);
-  
   data->ndi = *y++ ? true : false;
-  
-  // rv version
   data->rv_idx = srslte_bit_pack(&y, 2);
+  if (data->mcs_idx == 0 && data->rv_idx == 1) {
+    data->tb_en[0] = false; 
+  } else {
+    data->tb_en[0] = true; 
+  }
   
   // same for tb1
   data->mcs_idx_1 = srslte_bit_pack(&y, 5);  
   data->ndi_1 = *y++ ? true : false;  
   data->rv_idx_1 = srslte_bit_pack(&y, 2);
+  if (data->mcs_idx_1 == 0 && data->rv_idx_1 == 1) {
+    data->tb_en[1] = false; 
+  } else {
+    data->tb_en[1] = true; 
+  }
   
   // Precoding information 
   if (msg->format == SRSLTE_DCI_FORMAT2A) {
@@ -1069,7 +1081,6 @@ int dci_format2AB_unpack(srslte_dci_msg_t *msg, srslte_ra_dl_dci_t *data, uint32
     data->pinfo = srslte_bit_pack(&y, precoding_bits_f2a(nof_ports));
   }
   
-  data->nof_tb = 2; 
   
   return SRSLTE_SUCCESS;
 }

srslte/lib/phch/ra.c

@@ -172,6 +172,7 @@ int srslte_ra_ul_dci_to_grant_prb_allocation(srslte_ra_ul_dci_t *dci, srslte_ra_
 srslte_mod_t last_mod[8];
 uint32_t     last_ul_tbs_idx[8];
 uint32_t     last_dl_tbs[8];
+uint32_t     last_dl_tbs2[8];
 
 static int ul_dci_to_grant_mcs(srslte_ra_ul_dci_t *dci, srslte_ra_ul_grant_t *grant, uint32_t harq_pid) {  
   int tbs = -1; 
@@ -459,6 +460,8 @@ static int dl_dci_to_grant_mcs(srslte_ra_dl_dci_t *dci, srslte_ra_dl_grant_t *gr
     grant->mcs.tbs = (uint32_t) tbs; 
   } else {
     n_prb = grant->nof_prb;
+    grant->nof_tb = 0; 
+    if (dci->tb_en[0]) {
       grant->mcs.idx = dci->mcs_idx;
       tbs   = dl_fill_ra_mcs(&grant->mcs, n_prb);
       if (tbs) {
@@ -467,13 +470,28 @@ static int dl_dci_to_grant_mcs(srslte_ra_dl_dci_t *dci, srslte_ra_dl_grant_t *gr
         // For mcs>=29, set last TBS received for this PID
         grant->mcs.tbs = last_dl_tbs[dci->harq_process%8]; 
       }
-    if (dci->nof_tb == 2) {
+      grant->nof_tb++;
+    } else {
+      grant->mcs.tbs = 0; 
+    }
+    if (dci->tb_en[1]) {
       grant->mcs2.idx = dci->mcs_idx_1;
       tbs = dl_fill_ra_mcs(&grant->mcs2, n_prb);
+      if (tbs) {
+        last_dl_tbs2[dci->harq_process%8] = tbs;
+      } else {
+        // For mcs>=29, set last TBS received for this PID
+        grant->mcs2.tbs = last_dl_tbs2[dci->harq_process%8]; 
+      }
+      grant->nof_tb++;
+    } else {
+      grant->mcs2.tbs = 0; 
     }
   }  
+  if (dci->tb_en[0]) {
     grant->Qm = srslte_mod_bits_x_symbol(grant->mcs.mod);      
-  if (dci->nof_tb == 2) {
+  }
+  if (dci->tb_en[1]) {
     grant->Qm2 = srslte_mod_bits_x_symbol(grant->mcs2.mod);      
   }
   if (tbs < 0) {