add channel model option to rfsimulator and prevent common libraries re-compilation when using both --UE --eNB options in build_oai script

targets/ARCH/rfsimulator/channelmod.c

@@ -0,0 +1,97 @@
+/*
+  Author: Laurent THOMAS, Open Cells for Nokia
+  copyleft: OpenAirInterface Software Alliance and it's licence
+
+*/
+
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <errno.h>
+
+
+#include <common/utils/assertions.h>
+#include <common/utils/LOG/log.h>
+#include <common/config/config_userapi.h>
+#include <openair1/SIMULATION/TOOLS/sim.h>
+
+/*
+  Legacy study:
+  The parameters are:
+  gain&loss (decay, signal power, ...)
+  either a fixed gain in dB, a target power in dBm or ACG (automatic control gain) to a target average
+  => don't redo the AGC, as it was used in UE case, that must have a AGC inside the UE
+  will be better to handle the "set_gain()" called by UE to apply it's gain (enable test of UE power loop)
+  lin_amp = pow(10.0,.05*txpwr_dBm)/sqrt(nb_tx_antennas);
+  a lot of operations in legacy, grouped in one simulation signal decay: txgain*decay*rxgain
+
+  multi_path (auto convolution, ISI, ...)
+  either we regenerate the channel (call again random_channel(desc,0)), or we keep it over subframes
+  legacy: we regenerate each sub frame in UL, and each frame only in DL
+*/
+void rxAddInput( struct complex16 *input_sig, struct complex16 *after_channel_sig,
+                 int rxAnt,
+                 channel_desc_t *channelDesc,
+                 int nbSamples,
+                 uint64_t TS,
+                 uint32_t CirSize
+               ) {
+  // channelDesc->path_loss_dB should contain the total path gain
+  // so, in actual RF: tx gain + path loss + rx gain (+antenna gain, ...)
+  // UE and NB gain control to be added
+  // Fixme: not sure when it is "volts" so dB is 20*log10(...) or "power", so dB is 10*log10(...)
+  const double pathLossLinear = pow(10,channelDesc->path_loss_dB/20.0);
+  // Energy in one sample to calibrate input noise
+  //Fixme: modified the N0W computation, not understand the origin value
+  const double KT=1.38e-23*290; //Boltzman*temperature
+  // sampling rate is linked to acquisition band (the input pass band filter)
+  const double noise_figure_watt = KT*channelDesc->sampling_rate;
+  // Fixme: how to convert a noise in Watt into a 12 bits value out of the RF ADC ?
+  // the parameter "-s" is declared as SNR, but the input power is not well defined
+  // −132.24 dBm is a LTE subcarrier noise, that was used in origin code (15KHz BW thermal noise)
+  const double rxGain= 132.24 - snr_dB;
+  // sqrt(4*noise_figure_watt) is the thermal noise factor (volts)
+  // fixme: the last constant is pure trial results to make decent noise
+  const double noise_per_sample = sqrt(4*noise_figure_watt) * pow(10,rxGain/20) *10;
+  // Fixme: we don't fill the offset length samples at begining ?
+  // anyway, in today code, channel_offset=0
+  const int dd = abs(channelDesc->channel_offset);
+  const int nbTx=channelDesc->nb_tx;
+
+  for (int i=0; i<((int)nbSamples-dd); i++) {
+    struct complex16 *out_ptr=after_channel_sig+dd+i;
+    struct complex rx_tmp= {0};
+
+    for (int txAnt=0; txAnt < nbTx; txAnt++) {
+      const struct complex *channelModel= channelDesc->ch[rxAnt+(txAnt*channelDesc->nb_rx)];
+
+      //const struct complex *channelModelEnd=channelModel+channelDesc->channel_length;
+      for (int l = 0; l<(int)channelDesc->channel_length; l++) {
+        // let's assume TS+i >= l
+        // fixme: the rfsimulator current structure is interleaved antennas
+        // this has been designed to not have to wait a full block transmission
+        // but it is not very usefull
+        // it would be better to split out each antenna in a separate flow
+        // that will allow to mix ru antennas freely
+        struct complex16 tx16=input_sig[((TS+i-l)*nbTx+txAnt)%CirSize];
+        rx_tmp.x += tx16.r * channelModel[l].x - tx16.i * channelModel[l].y;
+        rx_tmp.y += tx16.i * channelModel[l].x + tx16.r * channelModel[l].y;
+      } //l
+    }
+
+    out_ptr->r += round(rx_tmp.x*pathLossLinear + noise_per_sample*gaussdouble(0.0,1.0));
+    out_ptr->i += round(rx_tmp.y*pathLossLinear + noise_per_sample*gaussdouble(0.0,1.0));
+    out_ptr++;
+  }
+
+  if ( (TS*nbTx)%CirSize+nbSamples <= CirSize )
+    // Cast to a wrong type for compatibility !
+    LOG_D(HW,"Input power %f, output power: %f, channel path loss %f, noise coeff: %f \n",
+          10*log10((double)signal_energy((int32_t *)&input_sig[(TS*nbTx)%CirSize], nbSamples)),
+          10*log10((double)signal_energy((int32_t *)after_channel_sig, nbSamples)),
+          channelDesc->path_loss_dB,
+          10*log10(noise_per_sample));
+}

targets/ARCH/rfsimulator/simulator.c

@@ -58,8 +58,9 @@ extern RAN_CONTEXT_t RC;
 #define RFSIMULATOR_PARAMS_DESC {\
     {"serveraddr",             "<ip address to connect to>\n",          0,         strptr:&(rfsimulator->ip),              defstrval:"127.0.0.1",           TYPE_STRING,    0 },\
     {"serverport",             "<port to connect to>\n",                0,         u16ptr:&(rfsimulator->port),            defuintval:PORT,                 TYPE_UINT16,    0 },\
-    {RFSIMU_OPTIONS_PARAMNAME, RFSIM_CONFIG_HELP_OPTIONS,               0,         strlistptr:NULL,                        defstrlistval:NULL,              TYPE_STRINGLIST,0}, \
-    {"IQfile",                 "<file path to use when saving IQs>\n",  0,         strptr:&(saveF),                        defstrval:"/tmp/rfsimulator.iqs",TYPE_STRING,    0 }\
+    {RFSIMU_OPTIONS_PARAMNAME, RFSIM_CONFIG_HELP_OPTIONS,               0,         strlistptr:NULL,                        defstrlistval:NULL,              TYPE_STRINGLIST,0},\
+    {"IQfile",                 "<file path to use when saving IQs>\n",  0,         strptr:&(saveF),                        defstrval:"/tmp/rfsimulator.iqs",TYPE_STRING,    0 },\
+    {"modelname",              "<channel model name>\n",                0,         strptr:&(modelname),                    defstrval:"AWGN",                TYPE_STRING,    0 }\
   };
 
 pthread_mutex_t Sockmutex;
@@ -220,6 +221,7 @@ void fullwrite(int fd, void *_buf, ssize_t count, rfsimulator_state_t *t) {
 
 void rfsimulator_readconfig(rfsimulator_state_t *rfsimulator) {
   char *saveF=NULL;
+  char *modelname=NULL;
   paramdef_t rfsimu_params[] = RFSIMULATOR_PARAMS_DESC;
   int p = config_paramidx_fromname(rfsimu_params,sizeof(rfsimu_params)/sizeof(paramdef_t), RFSIMU_OPTIONS_PARAMNAME) ;
   int ret = config_get( rfsimu_params,sizeof(rfsimu_params)/sizeof(paramdef_t),RFSIMU_SECTION);
@@ -237,7 +239,7 @@ void rfsimulator_readconfig(rfsimulator_state_t *rfsimulator) {
 
       break;
     } else if (strcmp(rfsimu_params[p].strlistptr[i],"chanmod") == 0) {
-      init_channelmod();
+      init_channelmod(modelname);
       rfsimulator->enable_channelmod=true;
     } else {
       fprintf(stderr,"Unknown rfsimulator option: %s\n",rfsimu_params[p].strlistptr[i]);