enb_amarisoft: add option to enable and configure DL AWGN channel

expose option to enable DL AWGN noise and make SNR configurable

Change-Id: Ib248e87e5abd855d4c974eab42ec40828c6e1d40

src/osmo_gsm_tester/obj/enb.py

@@ -36,6 +36,8 @@ def on_register_schemas():
         'rf_dev_args': schema.STR,
         'additional_args[]': schema.STR,
         'enable_measurements': schema.BOOL_STR,
+        'enable_dl_awgn': schema.BOOL_STR,
+        'dl_awgn_snr': schema.INT,
         'a1_report_type': schema.STR,
         'a1_report_value': schema.INT,
         'a1_hysteresis': schema.INT,

src/osmo_gsm_tester/obj/enb_amarisoft.py

@@ -160,6 +160,8 @@ class AmarisoftENB(enb.eNodeB):
         self.enable_measurements = util.str2bool(values['enb'].get('enable_measurements', 'false'))
         config.overlay(values, dict(enb={'enable_measurements': self.enable_measurements}))
 
+        config.overlay(values, dict(enb={'enable_dl_awgn': util.str2bool(values['enb'].get('enable_dl_awgn', 'false'))}))
+
         # We need to set some specific variables programatically here to match IP addresses:
         if self._conf.get('rf_dev_type') == 'zmq':
             base_srate = self.num_prb2base_srate(self.num_prb())

src/osmo_gsm_tester/templates/amarisoft_enb.cfg.tmpl

@@ -38,6 +38,13 @@
   /* RF driver configuration */
   include "amarisoft_rf_driver.cfg",
 
+% if enb.enable_dl_awgn:
+  channel_dl: {
+    type: "awgn",
+    snr: ${enb.dl_awgn_snr}
+  },
+% endif
+
   mme_list: [
     {
       s1ap_bind_addr: "${enb.addr}",

sysmocom/defaults.conf

@@ -113,6 +113,8 @@ enb:
   transmission_mode: 1
   num_cells: 1
   enable_measurements: false
+  enable_dl_awgn: false
+  dl_awgn_snr: 30
   a1_report_type: rsrp
   a1_report_value: -105
   a1_hysteresis: 0