make eNB UL SNR initial value an exponential average alpha configurable

lib/include/srsran/interfaces/sched_interface.h

@@ -62,6 +62,8 @@ public:
     float       max_delta_ul_snr        = 5;
     float       adaptive_link_step_size = 0.001;
     uint32_t    min_tpc_tti_interval    = 1;
+    float       ul_snr_avg_alpha        = 0.05;
+    int         init_ul_snr_value       = 5;
   };
 
   struct cell_cfg_t {

srsenb/enb.conf.example

@@ -174,6 +174,8 @@ enable = false
 # max_delta_ul_snr:  Maximum shift in UL SNR for adaptive UL link
 # adaptive_link_step_size: Step size or learning rate used in adaptive link
 # min_tpc_tti_interval: Minimum TTI interval between TPCs different than 1
+# ul_snr_avg_alpha:  Exponential Average alpha coefficient used in estimation of UL SNR
+# init_ul_snr_value: Initial UL SNR value used for computing MCS in the first UL grant
 #
 #####################################################################
 [scheduler]
@@ -194,6 +196,8 @@ enable = false
 #max_delta_ul_snr = 5
 #adaptive_link_step_size = 0.001
 #min_tpc_tti_interval = 1
+#ul_snr_avg_alpha=0.05
+#init_ul_snr_value=5
 
 #####################################################################
 # eMBMS configuration options

srsenb/hdr/stack/mac/sched_ue_ctrl/tpc.h

@@ -39,11 +39,14 @@ public:
                float    target_pucch_snr_dB_  = -1.0,
                float    target_pusch_sn_dB_   = -1.0,
                bool     phr_handling_flag_    = false,
-               uint32_t min_tpc_tti_interval_ = 1) :
+               uint32_t min_tpc_tti_interval_ = 1,
+               float    ul_snr_avg_alpha      = 0.05,
+               int      init_ul_snr_value     = 5) :
     nof_prb(cell_nof_prb),
     target_pucch_snr_dB(target_pucch_snr_dB_),
     target_pusch_snr_dB(target_pusch_sn_dB_),
-    snr_estim_list({ul_ch_snr_estim{target_pusch_snr_dB}, ul_ch_snr_estim{target_pucch_snr_dB}}),
+    snr_estim_list(
+        {ul_ch_snr_estim{ul_snr_avg_alpha, init_ul_snr_value}, ul_ch_snr_estim{ul_snr_avg_alpha, init_ul_snr_value}}),
     phr_handling_flag(phr_handling_flag_),
     max_prbs_cached(nof_prb),
     min_tpc_tti_interval(min_tpc_tti_interval_),
@@ -206,8 +209,8 @@ private:
     int                      acc_tpc_values     = 0;
     uint32_t                 last_tpc_tti_count = 0;
 
-    explicit ul_ch_snr_estim(float initial_snr) :
-      snr_avg(0.1, initial_snr < 0 ? 5 : initial_snr), win_tpc_values(FDD_HARQ_DELAY_UL_MS + FDD_HARQ_DELAY_DL_MS)
+    explicit ul_ch_snr_estim(float exp_avg_alpha, int initial_snr) :
+      snr_avg(exp_avg_alpha, initial_snr), win_tpc_values(FDD_HARQ_DELAY_UL_MS + FDD_HARQ_DELAY_DL_MS)
     {}
   };
   std::array<ul_ch_snr_estim, nof_ul_ch_code> snr_estim_list;

srsenb/src/main.cc

@@ -156,6 +156,8 @@ void parse_args(all_args_t* args, int argc, char* argv[])
     ("scheduler.max_delta_ul_snr", bpo::value<float>(&args->stack.mac.sched.max_delta_ul_snr)->default_value(5.0), "Maximum shift in UL SNR for adaptive UL link")
     ("scheduler.adaptive_link_step_size", bpo::value<float>(&args->stack.mac.sched.max_delta_ul_snr)->default_value(0.001), "Step size or learning rate used in adaptive link")
     ("scheduler.min_tpc_tti_interval", bpo::value<uint32_t>(&args->stack.mac.sched.min_tpc_tti_interval)->default_value(1), "Minimum TTI interval between positive or negative TPCs")
+    ("scheduler.ul_snr_avg_alpha", bpo::value<float>(&args->stack.mac.sched.ul_snr_avg_alpha)->default_value(0.05), "Exponential Average alpha coefficient used in estimation of UL SNR")
+    ("scheduler.init_ul_snr_value", bpo::value<int>(&args->stack.mac.sched.init_ul_snr_value)->default_value(5), "Initial UL SNR value used for computing MCS in the first UL grant")
 
 
     /* Downlink Channel emulator section */

srsenb/src/stack/mac/sched_ue_ctrl/sched_ue_cell.cc

@@ -39,7 +39,9 @@ sched_ue_cell::sched_ue_cell(uint16_t rnti_, const sched_cell_params_t& cell_cfg
           cell_cfg->cfg.target_pucch_ul_sinr,
           cell_cfg->cfg.target_pusch_ul_sinr,
           cell_cfg->cfg.enable_phr_handling,
-          cell_cfg->sched_cfg->min_tpc_tti_interval),
+          cell_cfg->sched_cfg->min_tpc_tti_interval,
+          cell_cfg->sched_cfg->ul_snr_avg_alpha,
+          cell_cfg->sched_cfg->init_ul_snr_value),
   fixed_mcs_dl(cell_cfg_.sched_cfg->pdsch_mcs),
   fixed_mcs_ul(cell_cfg_.sched_cfg->pusch_mcs),
   current_tti(current_tti_),