Do not change master clock rate if not necessary. Hint in ue/enb configs for low BW cells

lib/src/phy/rf/rf_uhd_imp.c

@@ -681,10 +681,8 @@ double rf_uhd_set_rx_srate(void* h, double freq)
   rf_uhd_handler_t* handler = (rf_uhd_handler_t*)h;
 
   // Set master clock rate
-  if (freq < 10e6) {
+  if (fmod(handler->current_master_clock, freq)) {
     rf_uhd_set_master_clock_rate(handler, 4 * freq);
-  } else {
-    rf_uhd_set_master_clock_rate(handler, freq);
   }
 
   if (handler->nof_rx_channels > 1) {
@@ -716,10 +714,8 @@ double rf_uhd_set_tx_srate(void* h, double freq)
   rf_uhd_handler_t* handler = (rf_uhd_handler_t*)h;
 
   // Set master clock rate
-  if (freq < 10e6) {
+  if (fmod(handler->current_master_clock, freq)) {
     rf_uhd_set_master_clock_rate(handler, 4 * freq);
-  } else {
-    rf_uhd_set_master_clock_rate(handler, freq);
   }
 
   if (handler->nof_tx_channels > 1) {

srsenb/enb.conf.example

@@ -73,7 +73,10 @@ rx_gain = 40
 #device_name = auto
 
 # For best performance in 2x2 MIMO and >= 15 MHz use the following device_args settings:
-#     USRP B210: pass num_recv_frames=64,num_send_frames=64
+#     USRP B210: num_recv_frames=64,num_send_frames=64
+
+# For best performance when BW<5 MHz (25 PRB), use the following device_args settings:
+#     USRP B210: send_frame_size=512,recv_frame_size=512
 
 #device_args = auto
 #time_adv_nsamples = auto

srsue/ue.conf.example

@@ -40,7 +40,10 @@ tx_gain = 80
 #nof_rx_ant = 1
 
 # For best performance in 2x2 MIMO and >= 15 MHz use the following device_args settings:
-#     USRP B210: pass num_recv_frames=64,num_send_frames=64
+#     USRP B210: num_recv_frames=64,num_send_frames=64
+
+# For best performance when BW<5 MHz (25 PRB), use the following device_args settings:
+#     USRP B210: send_frame_size=512,recv_frame_size=512
 
 #device_args = auto
 #time_adv_nsamples = auto