Fix EMA cold-start for noise and SNR/RSSI measurements

Initialize n0_subband_power and power control avg_snr/avg_rssi directly from the first measurement instead of starting from zero

openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c

@@ -162,6 +162,7 @@ void gNB_I0_measurements(PHY_VARS_gNB *gNB, int slot, int first_symb, int num_sy
   int32_t n0_subband_tot_perANT[frame_parms->nb_antennas_rx];
   memset(n0_subband_tot_perANT, 0, sizeof(n0_subband_tot_perANT));
 
+  bool init_meas = measurements->n0_subband_power == NULL;
   allocCast2D(n0_subband_power,
               unsigned int,
               measurements->n0_subband_power,
@@ -174,6 +175,9 @@ void gNB_I0_measurements(PHY_VARS_gNB *gNB, int slot, int first_symb, int num_sy
     if (nb_symb[rb] > 0) {
       for (int aarx = 0; aarx < frame_parms->nb_antennas_rx; aarx++) {
         tmp_n0_subband[aarx][rb] /= nb_symb[rb];
+        // Initialize n0_subband_power from the first measurement before EMA
+        if (init_meas)
+          n0_subband_power[aarx][rb] = tmp_n0_subband[aarx][rb];
         // apply exponential moving average to smooth noise measurements
         n0_subband_power[aarx][rb] = 0.9 * n0_subband_power[aarx][rb] + 0.1 * tmp_n0_subband[aarx][rb];
         n0_subband_tot_perPRB += n0_subband_power[aarx][rb];

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_uci.c

@@ -910,6 +910,11 @@ void handle_nr_uci_pucch_0_1(module_id_t mod_id, frame_t frame, slot_t slot, con
           NR_SCHED_UNLOCK(&nrmac->sched_lock);
           return;
         }
+        // Msg4 Ack: reset average with first measurement
+        if (uci_01->ul_cqi != 0xff) {
+          UE->UE_sched_ctrl.pucch_pc.avg_rssi = uci_01->rssi;
+          UE->UE_sched_ctrl.pucch_pc.avg_snr = (uci_01->ul_cqi * 5 - 640) * 0.1;
+        }
       }
       if (harq_confidence == 1) {
         UE->mac_stats.pucch0_DTX++;

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_ulsch.c

@@ -763,7 +763,7 @@ static void nr_rx_ra_sdu(const module_id_t mod_id,
 
   if (ul_cqi != 0xff) {
     NR_UE_sched_ctrl_t *sched_ctrl = &UE->UE_sched_ctrl;
-    // Msg3: reset average. If this fails (e.g., ul_cqi == 0xff)
+    // Msg3: reset average with first measurement. If this fails (e.g., ul_cqi == 0xff)
     // everything starts from predetermined value
     sched_ctrl->pusch_pc.avg_snr = 0.1 * (ul_cqi * 5 - 640);
     sched_ctrl->pusch_pc.avg_rssi = rssi;