Adding CL option -P to simulate the propagation delay in the RF simulator

executables/nr-softmodem-common.h

@@ -110,6 +110,7 @@
 #define CONFIG_HLP_SNR           "Set average SNR in dB (for --siml1 option)\n"
 #define CONFIG_HLP_NOS1          "Disable s1 interface\n"
 #define CONFIG_HLP_NOKRNMOD      "(noS1 only): Use tun instead of namesh module \n"
+#define CONFIG_HLP_PROPD         "Set propagation delay in the RF simulator (expressed in number of samples)\n"
 /*--------------------------------------------------------------------------------------------------------------------------------*/
 /*                                            command line parameters for LOG utility                                             */
 /*   optname         helpstr          paramflags          XXXptr                     defXXXval            type           numelt   */
@@ -154,4 +155,6 @@ extern int emulate_rf;
 extern int numerology;
 extern int usrp_tx_thread;
 
+extern uint64_t RFsim_PropDelay; //propagation delay in the RF simulator (expressed in number of samples)
+
 #endif

executables/nr-softmodem.c

@@ -568,6 +568,8 @@ void init_pdcp(void) {
   }
 }
 
+uint64_t RFsim_PropDelay = 0;
+
 int main( int argc, char **argv ) {
   int ru_id, CC_id = 0;
   start_background_system();

executables/nr-softmodem.h

@@ -32,6 +32,7 @@
   {"ldpc-offload-enable",   CONFIG_HLP_LDPC_OFFLOAD,   0,                .iptr=&ldpc_offload_flag,            .defstrval=0,                     TYPE_INT,    0},        \
   {"uecap_file",            CONFIG_HLP_UECAP_FILE,     0,                .strptr=&uecap_file,                 .defstrval="./uecap_ports1.xml",  TYPE_STRING, 0},        \
   {"s" ,                    CONFIG_HLP_SNR,            0,                .dblptr=&snr_dB,                     .defdblval=25,                    TYPE_DOUBLE, 0},        \
+  {"P" ,                    CONFIG_HLP_PROPD,          0,                .u64ptr=&RFsim_PropDelay,            .defintval=0,                     TYPE_UINT64, 0},        \
 }
 // clang-format on
 

executables/nr-uesoftmodem.c

@@ -424,6 +424,7 @@ static void get_channel_model_mode() {
 }
 
 int NB_UE_INST = 1;
+uint64_t RFsim_PropDelay = 0;
 
 int main( int argc, char **argv ) {
   int set_exe_prio = 1;

executables/nr-uesoftmodem.h

@@ -63,6 +63,7 @@
   {"chest-time",                   CONFIG_HLP_CHESTTIME,       0,               .iptr=&(nrUE_params.chest_time),             .defintval=0,      TYPE_INT,      0}, \
   {"ue-timing-correction-disable", CONFIG_HLP_DISABLETIMECORR, PARAMFLAG_BOOL,  .iptr=&(nrUE_params.no_timing_correction),   .defintval=0,      TYPE_INT,      0}, \
   {"SLC",                          CONFIG_HLP_SLF,             0,               .u64ptr=&(sidelink_frequency[0][0]),         .defuintval=2600000000,TYPE_UINT64,0}, \
+  {"P" ,                           CONFIG_HLP_PROPD,           0,               .u64ptr=&RFsim_PropDelay,                    .defintval=0,      TYPE_UINT64,   0}, \
 }
 // clang-format on
 

radio/rfsimulator/simulator.c

@@ -54,7 +54,7 @@
 #include "rfsimulator.h"
 
 #define PORT 4043 //default TCP port for this simulator
-#define CirSize 6144000 // 100ms is enough
+#define CirSize 61440000 //curently the circular buffer can hold 100 frames
 #define sampleToByte(a,b) ((a)*(b)*sizeof(sample_t))
 #define byteToSample(a,b) ((a)/(sizeof(sample_t)*(b)))
 
@@ -602,6 +602,7 @@ static int startClient(openair0_device *device) {
   return 0;
 }
 
+extern uint64_t RFsim_PropDelay;
 static int rfsimulator_write_internal(rfsimulator_state_t *t, openair0_timestamp timestamp, void **samplesVoid, int nsamps, int nbAnt, int flags, bool alreadyLocked) {
   if (!alreadyLocked)
     pthread_mutex_lock(&Sockmutex);
@@ -877,7 +878,7 @@ static int rfsimulator_read(openair0_device *device, openair0_timestamp *ptimest
                      a,
                      ptr->channel_model,
                      nsamps,
-                     t->nextRxTstamp,
+                     t->nextRxTstamp-RFsim_PropDelay,
                      CirSize);
         }
         else { // no channel modeling
@@ -893,8 +894,8 @@ static int rfsimulator_read(openair0_device *device, openair0_timestamp *ptimest
           //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 += (short)(ptr->circularBuf[((t->nextRxTstamp+i)*nbAnt_tx+a_tx)%CirSize].r*H_awgn_mimo[a][a_tx]);
-              out[i].i += (short)(ptr->circularBuf[((t->nextRxTstamp+i)*nbAnt_tx+a_tx)%CirSize].i*H_awgn_mimo[a][a_tx]);
+              out[i].r += (short)(ptr->circularBuf[((t->nextRxTstamp-RFsim_PropDelay+i)*nbAnt_tx+a_tx)%CirSize].r*H_awgn_mimo[a][a_tx]);
+              out[i].i += (short)(ptr->circularBuf[((t->nextRxTstamp-RFsim_PropDelay+i)*nbAnt_tx+a_tx)%CirSize].i*H_awgn_mimo[a][a_tx]);
             } // end for a_tx
           } // end for i (number of samps)
         } // end of no channel modeling