fix for TDD: TX is powered on a few samples earlier to allow it to settle before start of DL

targets/RT/USER/lte-enb.c

@@ -948,12 +948,11 @@ void rx_rf(PHY_VARS_eNB *eNB,int *frame,int *subframe) {
     lte_subframe_t SF_type     = subframe_select(fp,(proc->subframe_rx+tx_sfoffset)%10);
     lte_subframe_t prevSF_type = subframe_select(fp,(proc->subframe_rx+tx_sfoffset+9)%10);
     lte_subframe_t nextSF_type = subframe_select(fp,(proc->subframe_rx+tx_sfoffset+1)%10);
+    int sf_extension = 0; 
+
     if ((SF_type == SF_DL) ||
 	(SF_type == SF_S)) {
 
-      for (i=0; i<fp->nb_antennas_tx; i++)
-	txp[i] = (void*)&eNB->common_vars.txdata[0][i][((proc->subframe_rx+tx_sfoffset)%10)*fp->samples_per_tti]; 
-
       int siglen=fp->samples_per_tti,flags=1;
 
       if (SF_type == SF_S) {
@@ -962,22 +961,29 @@ void rx_rf(PHY_VARS_eNB *eNB,int *frame,int *subframe) {
       }
       if ((fp->frame_type == TDD) &&
 	  (SF_type == SF_DL)&&
-	  (prevSF_type == SF_UL) &&
-	  (nextSF_type == SF_DL))
+	  (prevSF_type == SF_UL) && 
+	  (nextSF_type == SF_DL)) {
 	flags = 2; // start of burst
-
+	//sf_extension = eNB->N_TA_offset<<1;
+      }
       if ((fp->frame_type == TDD) &&
 	  (SF_type == SF_DL)&&
 	  (prevSF_type == SF_UL) &&
-	  (nextSF_type == SF_UL))
+	  (nextSF_type == SF_UL)) {
 	flags = 4; // start of burst and end of burst (only one DL SF between two UL)
+	//sf_extension = eNB->N_TA_offset<<1;
+      }
      
       VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME( VCD_SIGNAL_DUMPER_FUNCTIONS_TRX_WRITE, 1 );
       VCD_SIGNAL_DUMPER_DUMP_VARIABLE_BY_NAME( VCD_SIGNAL_DUMPER_VARIABLES_TRX_WRITE_FLAGS,flags); 
+
+      for (i=0; i<fp->nb_antennas_tx; i++)
+	txp[i] = (void*)&eNB->common_vars.txdata[0][i][((proc->subframe_rx+tx_sfoffset)%10)*fp->samples_per_tti-sf_extension]; 
+
       txs = eNB->rfdevice.trx_write_func(&eNB->rfdevice,
-					 proc->timestamp_rx+eNB->ts_offset+(tx_sfoffset*fp->samples_per_tti)-openair0_cfg[0].tx_sample_advance,
+					 proc->timestamp_rx+eNB->ts_offset+(tx_sfoffset*fp->samples_per_tti)-openair0_cfg[0].tx_sample_advance-sf_extension,
 					 txp,
-					 siglen,
+					 siglen+sf_extension,
 					 fp->nb_antennas_tx,
 					 flags);
       clock_gettime( CLOCK_MONOTONIC, &end_rf);    
@@ -991,7 +997,7 @@ void rx_rf(PHY_VARS_eNB *eNB,int *frame,int *subframe) {
       
       
       
-      if (txs !=  siglen) {
+      if (txs !=  siglen+sf_extension) {
 	LOG_E(PHY,"TX : Timeout (sent %d/%d)\n",txs, fp->samples_per_tti);
 	exit_fun( "problem transmitting samples" );
       }