Extend rfsim to enable muti transmit antennas for gNB+solve beamforming ssb_index 0 when nb_tx>1

targets/ARCH/rfsimulator/simulator.c

@@ -510,7 +510,7 @@ static bool flushInput(rfsimulator_state_t *t, int timeout, int nsamps_for_initi
           LOG_E(HW,"UEsock: %d Tx/Rx shift too large Tx:%lu, Rx:%lu\n", fd, t->lastWroteTS, b->lastReceivedTS);
 
         pthread_mutex_unlock(&Sockmutex);
-        b->transferPtr=(char *)&b->circularBuf[b->lastReceivedTS%CirSize];
+        b->transferPtr=(char *)&b->circularBuf[(b->lastReceivedTS*b->th.nbAnt)%CirSize];
         b->remainToTransfer=sampleToByte(b->th.size, b->th.nbAnt);
       }
 
@@ -641,7 +641,7 @@ int rfsimulator_read(openair0_device *device, openair0_timestamp *ptimestamp, vo
       if (reGenerateChannel)
         random_channel(ptr->channel_model,0);
 
-      for (int a=0; a<nbAnt; a++) {
+      for (int a=0; a<nbAnt; a++) {//loop over number of Rx antennas
         if ( ptr->channel_model != NULL ) // apply a channel model
           rxAddInput( ptr->circularBuf, (struct complex16 *) samplesVoid[a],
                       a,
@@ -652,14 +652,16 @@ int rfsimulator_read(openair0_device *device, openair0_timestamp *ptimestamp, vo
                     );
         else { // no channel modeling
           sample_t *out=(sample_t *)samplesVoid[a];
-          const int64_t base=t->nextTimestamp*nbAnt+a;
-          for ( int i=0; i < nsamps; i++ ) {
-	    const int idx=(i*nbAnt+base)%CirSize;
-            out[i].r+=ptr->circularBuf[idx].r;
-            out[i].i+=ptr->circularBuf[idx].i;
-          }
+          int nbAnt_tx = ptr->th.nbAnt;//number of Tx antennas
+          //LOG_I(HW, "nbAnt_tx %d\n",nbAnt_tx);
+          for (int i=0; i < nsamps; i++) {//loop over nsamps
+        	  for (int a_tx=0; a_tx<nbAnt_tx; a_tx++){//sum up signals from nbAnt_tx antennas
+        		  out[i].r+=ptr->circularBuf[((t->nextTimestamp+i)*nbAnt_tx+a_tx)%CirSize].r;
+        		  out[i].i+=ptr->circularBuf[((t->nextTimestamp+i)*nbAnt_tx+a_tx)%CirSize].i;
+        	  } // end for a_tx
+          } // end for i (number of samps)
         } // end of no channel modeling
-      } // end for a...
+      } // end for a (number of rx antennas)
     }
   }