[overpower] Turn it on and off depending on DL RxQual

Change-Id: Iaa812d4661ee17c4cd4a8c4ae4bd3e94c1a2e6cc
Depends: Ia28293a12de0af71f55e701fb65c46e905dae217
Related: SYS#5319

include/osmo-bts/lchan.h

@@ -293,8 +293,9 @@ struct gsm_lchan {
 	struct gsm_power_ctrl_params ms_dpc_params;
 	struct gsm_power_ctrl_params bs_dpc_params;
 
-	/* Temporary ACCH overpower capabilities */
+	/* Temporary ACCH overpower capabilities and state */
 	struct abis_rsl_osmo_temp_ovp_acch_cap top_acch_cap;
+	bool top_acch_active;
 
 	struct msgb *pending_rel_ind_msg;
 

src/common/measurement.c

@@ -861,6 +861,43 @@ out:
 		LOGPLCHAN(lchan, DL1P, LOGL_DEBUG, "DL-FACCH repetition: active => inactive\n");
 }
 
+static void acch_overpower_active_decision(struct gsm_lchan *lchan,
+					   const struct gsm48_meas_res *meas_res)
+{
+	const bool old = lchan->top_acch_active;
+	uint8_t upper, lower, rxqual;
+
+	/* ACCH overpower is not allowed => nothing to do */
+	if (lchan->top_acch_cap.overpower_db == 0)
+		return;
+	/* RxQual threshold is disabled => overpower is always on */
+	if (lchan->top_acch_cap.rxqual == 0)
+		return;
+
+	/* If DTx is active on Downlink, use the '-SUB' */
+	if (meas_res->dtx_used)
+		rxqual = meas_res->rxqual_sub;
+	else /* ... otherwise use the '-FULL' */
+		rxqual = meas_res->rxqual_full;
+
+	upper = lchan->top_acch_cap.rxqual;
+	if (upper > 2)
+		lower = upper - 2;
+	else
+		lower = 0;
+
+	if (rxqual >= upper)
+		lchan->top_acch_active = true;
+	else if (rxqual <= lower)
+		lchan->top_acch_active = false;
+
+	if (lchan->top_acch_active != old) {
+		LOGPLCHAN(lchan, DL1P, LOGL_DEBUG, "Temporary ACCH overpower: %s\n",
+			  lchan->top_acch_active ? "inactive => active"
+						  : "active => inactive");
+	}
+}
+
 static bool data_is_rr_meas_rep(const uint8_t *data)
 {
 	const struct gsm48_hdr *gh = (void *)(data + 5);
@@ -954,8 +991,10 @@ void lchan_meas_handle_sacch(struct gsm_lchan *lchan, struct msgb *msg)
 	}
 	lchan_ms_ta_ctrl(lchan, ms_ta, lchan->meas.ms_toa256);
 	lchan_ms_pwr_ctrl(lchan, ms_pwr, ul_rssi, ul_ci_cb);
-	if (mr && mr->meas_valid == 0) /* 0 = valid */
+	if (mr && mr->meas_valid == 0) { /* 0 = valid */
 		lchan_bs_pwr_ctrl(lchan, mr);
+		acch_overpower_active_decision(lchan, mr);
+	}
 
 	repeated_dl_facch_active_decision(lchan, mr);
 

src/common/rsl.c

@@ -1928,6 +1928,13 @@ static int rsl_rx_chan_activ(struct msgb *msg)
 	if (rc < 0)
 		return rsl_tx_chan_act_acknack(lchan, -rc);
 
+	/* Take the first ACCH overpower decision (if allowed): it can be
+	 * enabled immediately if the RxQual threshold is disabled (0). */
+	if (lchan->top_acch_cap.overpower_db > 0)
+		lchan->top_acch_active = !lchan->top_acch_cap.rxqual;
+	else
+		lchan->top_acch_active = false;
+
 	/* actually activate the channel in the BTS */
 	rc = l1sap_chan_act(lchan->ts->trx, dch->chan_nr, &tp);
 	if (rc < 0)
@@ -2198,6 +2205,13 @@ static int rsl_rx_mode_modif(struct msgb *msg)
 	if (rc < 0)
 		return rsl_tx_mode_modif_nack(lchan, -rc);
 
+	/* Immediately disable ACCH overpower if the value is 0 dB,
+	 * or enable if the RxQual threshold becomes disabled (0). */
+	if (lchan->top_acch_cap.overpower_db == 0)
+		lchan->top_acch_active = false;
+	else if (lchan->top_acch_cap.rxqual == 0)
+		lchan->top_acch_active = true;
+
 	l1sap_chan_modify(lchan->ts->trx, dch->chan_nr);
 
 	/* FIXME: delay this until L1 says OK? */

src/common/scheduler.c

@@ -1310,7 +1310,7 @@ static void trx_sched_apply_att(const struct gsm_lchan *lchan,
 	br->att = lchan->bs_power_ctrl.current;
 
 	/* Temporary Overpower for SACCH/FACCH bursts */
-	if (lchan->top_acch_cap.overpower_db == 0)
+	if (!lchan->top_acch_active)
 		return;
 	if ((lchan->top_acch_cap.sacch_enable && desc->link_id == LID_SACCH) ||
 	    (lchan->top_acch_cap.facch_enable && br->flags & TRX_BR_F_FACCH)) {