Added option to ue.conf to configure CFO EMA (set default to 0.4)

lib/include/srslte/interfaces/ue_interfaces.h

@@ -446,6 +446,7 @@ typedef struct {
   std::string snr_estim_alg; 
   bool cfo_integer_enabled; 
   float cfo_correct_tol_hz;
+  float cfo_ema;
   int time_correct_period; 
   bool sfo_correct_disable; 
   std::string sss_algorithm; 

lib/include/srslte/phy/ue/ue_sync.h

@@ -187,6 +187,9 @@ SRSLTE_API void srslte_ue_sync_set_cfo_tol(srslte_ue_sync_t *q,
 SRSLTE_API void srslte_ue_sync_set_cfo(srslte_ue_sync_t *q, 
                                        float cfo);
 
+SRSLTE_API void srslte_ue_sync_set_cfo_ema(srslte_ue_sync_t *q,
+                                           float ema);
+
 SRSLTE_API void srslte_ue_sync_cfo_i_detec_en(srslte_ue_sync_t *q, 
                                               bool enable); 
 

lib/src/phy/ue/ue_sync.c

@@ -359,6 +359,11 @@ uint32_t srslte_ue_sync_peak_idx(srslte_ue_sync_t *q) {
   return q->peak_idx;
 }
 
+void srslte_ue_sync_set_cfo_ema(srslte_ue_sync_t *q, float ema) {
+  srslte_sync_set_cfo_ema_alpha(&q->sfind, ema);
+  srslte_sync_set_cfo_ema_alpha(&q->strack, ema);
+}
+
 srslte_ue_sync_state_t srslte_ue_sync_get_state(srslte_ue_sync_t *q) {
   return q->state;
 }

srsue/src/main.cc

@@ -202,6 +202,11 @@ void parse_args(all_args_t *args, int argc, char *argv[]) {
      bpo::value<float>(&args->expert.phy.cfo_correct_tol_hz)->default_value(50.0),
      "Tolerance (in Hz) for digial CFO compensation.")
 
+    ("expert.cfo_ema",
+     bpo::value<float>(&args->expert.phy.cfo_ema)->default_value(0.4),
+     "CFO Exponential Moving Average coefficient. Lower makes it more robust to noise "
+     "but vulnerable to periodic interruptions due to VCO corrections.")
+
     ("expert.time_correct_period",
      bpo::value<int>(&args->expert.phy.time_correct_period)->default_value(5),
      "Period for sampling time offset correction.")

srsue/src/phy/phch_recv.cc

@@ -209,6 +209,7 @@ void phch_recv::set_ue_sync_opts(srslte_ue_sync_t *q) {
     srslte_ue_sync_cfo_i_detec_en(q, true);
   }
 
+  srslte_ue_sync_set_cfo_ema(q, worker_com->args->cfo_ema);
   srslte_ue_sync_set_cfo_tol(q, worker_com->args->cfo_correct_tol_hz);
 
   int time_correct_period = worker_com->args->time_correct_period;

srsue/ue.conf.example

@@ -98,7 +98,10 @@ enable = false
 #####################################################################
 # Expert configuration options
 #
+# ue_category:          Sets UE category (range 1-5). Default: 4
 # ip_netmask:           Netmask of the tun_srsue device. Default: 255.255.255.0
+# rssi_sensor_enabled:  Enable or disable RF frontend RSSI sensor. Required for RSRP metrics but
+#                       can cause UHD instability for long-duration testing. Default true.
 # ue_category:          Sets UE category (range 1-5). Default: 4
 #
 # prach_gain:           PRACH gain (dB). If defined, forces a gain for the tranmsission of PRACH only., 
@@ -117,6 +120,8 @@ enable = false
 # equalizer_mode:       Selects equalizer mode. Valid modes are: "mmse", "zf" or any 
 #                       non-negative real number to indicate a regularized zf coefficient.
 #                       Default is MMSE.
+# cfo_ema:              CFO Exponential Moving Average coefficient. Lower makes it more robust to noise
+#                       but vulnerable to periodic interruptions due to VCO corrections.
 # cfo_integer_enabled:  Enables integer CFO estimation and correction. This needs improvement
 #                       and may lead to incorrect synchronization. Use with caution. 
 # cfo_correct_tol_hz:   Tolerance (in Hz) for digial CFO compensation. Lower tolerance means that 
@@ -140,6 +145,7 @@ enable = false
 #####################################################################
 [expert]
 #ip_netmask          = 255.255.255.0
+#rssi_sensor_enabled = false
 #ue_category         = 4
 #prach_gain          = 30
 #cqi_max             = 15
@@ -150,6 +156,7 @@ enable = false
 #attach_enable_64qam = false
 #nof_phy_threads     = 2
 #equalizer_mode      = mmse
+#cfo_ema             = 0.4
 #cfo_integer_enabled = false
 #cfo_correct_tol_hz  = 50
 #time_correct_period = 5