<p>pespin has uploaded this change for <strong>review</strong>.</p><p><a href="https://gerrit.osmocom.org/c/osmo-bts/+/25503">View Change</a></p><pre style="font-family: monospace,monospace; white-space: pre-wrap;">MS Power Control Loop: Fix oscillations within good MS Power Levels<br><br>Related: SYS#4917<br>Change-Id: Ib33a94eba92004f9327c91e020a506dfa9a957c3<br>---<br>M src/common/power_control.c<br>M tests/power/ms_power_loop_test.c<br>M tests/power/ms_power_loop_test.err<br>M tests/power/ms_power_loop_test.ok<br>4 files changed, 44 insertions(+), 19 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;">git pull ssh://gerrit.osmocom.org:29418/osmo-bts refs/changes/03/25503/1</pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/src/common/power_control.c b/src/common/power_control.c</span><br><span>index 62905bd..a29d6db 100644</span><br><span>--- a/src/common/power_control.c</span><br><span>+++ b/src/common/power_control.c</span><br><span>@@ -199,6 +199,7 @@</span><br><span> uint8_t rxlev_avg;</span><br><span> int16_t ul_lqual_cb_avg;</span><br><span> const struct gsm_power_ctrl_meas_params *ci_meas;</span><br><span style="color: hsl(120, 100%, 40%);">+ bool ignore;</span><br><span> </span><br><span> if (!trx_ms_pwr_ctrl_is_osmo(trx))</span><br><span> return 0;</span><br><span>@@ -265,15 +266,39 @@</span><br><span> }</span><br><span> </span><br><span> current_dbm = ms_pwr_dbm(band, state->current);</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ /* In this Power Control Loop, we infer a new good MS Power Level based</span><br><span style="color: hsl(120, 100%, 40%);">+ * on the previous MS Power Level announced by the MS (not the previous</span><br><span style="color: hsl(120, 100%, 40%);">+ * one we requested!) together with the related computed measurements.</span><br><span style="color: hsl(120, 100%, 40%);">+ * Hence, and since we allow for several good MS Power Levels falling into our</span><br><span style="color: hsl(120, 100%, 40%);">+ * thresholds, we could finally converge into an oscillation loop where</span><br><span style="color: hsl(120, 100%, 40%);">+ * the MS bounces between 2 different correct MS Power levels all the</span><br><span style="color: hsl(120, 100%, 40%);">+ * time, due to the fact that we "accept" and "request back" whatever</span><br><span style="color: hsl(120, 100%, 40%);">+ * good MS Power Level we received from the MS, but at that time the MS</span><br><span style="color: hsl(120, 100%, 40%);">+ * will be transmitting using the previous MS Powever Level we</span><br><span style="color: hsl(120, 100%, 40%);">+ * requested, which we will later "accept" and "request back" on next loop</span><br><span style="color: hsl(120, 100%, 40%);">+ * iteration. As a result MS effectively bounces between those 2 MS</span><br><span style="color: hsl(120, 100%, 40%);">+ * Power Levels.</span><br><span style="color: hsl(120, 100%, 40%);">+ * In order to fix this permanent oscillation, if current MS_PWR used/announced</span><br><span style="color: hsl(120, 100%, 40%);">+ * by MS is good ("ms_dbm == new_dbm", hence within thresholds and no change</span><br><span style="color: hsl(120, 100%, 40%);">+ * required) but has higher Tx power than the one we last requested, we ignore</span><br><span style="color: hsl(120, 100%, 40%);">+ * it and keep requesting for one with lower Tx power. This way we converge to</span><br><span style="color: hsl(120, 100%, 40%);">+ * the lowest good Tx power avoiding oscillating over values within thresholds.</span><br><span style="color: hsl(120, 100%, 40%);">+ */</span><br><span style="color: hsl(120, 100%, 40%);">+ ignore = (ms_dbm == new_dbm && ms_dbm > current_dbm);</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> LOGPLCHAN(lchan, DLOOP, LOGL_INFO, "%s MS power control level %d (%d dBm) => %d (%d dBm): "</span><br><span> "ms-pwr-lvl[curr %" PRIu8 ", max %" PRIu8 "], RSSI[curr %d, avg %d, thresh %d..%d] dBm,"</span><br><span> " C/I[curr %d, avg %d, thresh %d..%d] dB\n",</span><br><span style="color: hsl(0, 100%, 40%);">- (new_dbm > current_dbm) ? "Raising" : "Lowering",</span><br><span style="color: hsl(120, 100%, 40%);">+ ignore ? "Ignoring" : ((new_dbm > current_dbm) ? "Raising" : "Lowering"),</span><br><span> state->current, current_dbm, new_power_lvl, new_dbm, ms_power_lvl,</span><br><span> state->max, ul_rssi_dbm, rxlev2dbm(rxlev_avg),</span><br><span> rxlev2dbm(params->rxlev_meas.lower_thresh), rxlev2dbm(params->rxlev_meas.upper_thresh),</span><br><span> ul_lqual_cb/10, ul_lqual_cb_avg/10, ci_meas->lower_thresh, ci_meas->upper_thresh);</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+ if (ignore)</span><br><span style="color: hsl(120, 100%, 40%);">+ return 0;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> /* store the resulting new MS power level in the lchan */</span><br><span> state->current = new_power_lvl;</span><br><span> bts_model_adjst_ms_pwr(lchan);</span><br><span>diff --git a/tests/power/ms_power_loop_test.c b/tests/power/ms_power_loop_test.c</span><br><span>index d8d1c71..a343ee2 100644</span><br><span>--- a/tests/power/ms_power_loop_test.c</span><br><span>+++ b/tests/power/ms_power_loop_test.c</span><br><span>@@ -398,11 +398,11 @@</span><br><span> lchan->ms_power_ctrl.current = 10;</span><br><span> lchan->ms_power_ctrl.max = 2;</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">- apply_power_test_ext(lchan, 9, good_rxlev, good_lqual, 1, 9);</span><br><span style="color: hsl(0, 100%, 40%);">- apply_power_test_ext(lchan, 10, good_rxlev, good_lqual, 1, 10);</span><br><span style="color: hsl(0, 100%, 40%);">- apply_power_test_ext(lchan, 9, good_rxlev, good_lqual, 1, 9);</span><br><span style="color: hsl(0, 100%, 40%);">- apply_power_test_ext(lchan, 10, good_rxlev, good_lqual, 1, 10);</span><br><span style="color: hsl(0, 100%, 40%);">- apply_power_test_ext(lchan, 9, good_rxlev, good_lqual, 1, 9);</span><br><span style="color: hsl(120, 100%, 40%);">+ apply_power_test_ext(lchan, 9, good_rxlev, good_lqual, 1, 10);</span><br><span style="color: hsl(120, 100%, 40%);">+ apply_power_test_ext(lchan, 10, good_rxlev, good_lqual, 0, 10);</span><br><span style="color: hsl(120, 100%, 40%);">+ apply_power_test_ext(lchan, 9, good_rxlev, good_lqual, 0, 10);</span><br><span style="color: hsl(120, 100%, 40%);">+ apply_power_test_ext(lchan, 10, good_rxlev, good_lqual, 0, 10);</span><br><span style="color: hsl(120, 100%, 40%);">+ apply_power_test_ext(lchan, 9, good_rxlev, good_lqual, 0, 10);</span><br><span> }</span><br><span> </span><br><span> int main(int argc, char **argv)</span><br><span>diff --git a/tests/power/ms_power_loop_test.err b/tests/power/ms_power_loop_test.err</span><br><span>index 5a68e3b..a85b9b2 100644</span><br><span>--- a/tests/power/ms_power_loop_test.err</span><br><span>+++ b/tests/power/ms_power_loop_test.err</span><br><span>@@ -58,8 +58,8 @@</span><br><span> (bts=0,trx=0,ts=0,ss=0) Lowering MS power control level 11 (8 dBm) => 12 (6 dBm): ms-pwr-lvl[curr 11, max 2], RSSI[curr -100, avg -100, thresh -75..-75] dBm, C/I[curr 17, avg 17, thresh 12..16] dB</span><br><span> (bts=0,trx=0,ts=0,ss=0) Lowering MS power control level 12 (6 dBm) => 13 (4 dBm): ms-pwr-lvl[curr 12, max 2], RSSI[curr -60, avg -60, thresh -75..-75] dBm, C/I[curr 14, avg 14, thresh 12..16] dB</span><br><span> (bts=0,trx=0,ts=0,ss=0) Lowering MS power control level 13 (4 dBm) => 14 (2 dBm): ms-pwr-lvl[curr 13, max 2], RSSI[curr -60, avg -60, thresh -75..-75] dBm, C/I[curr 17, avg 17, thresh 12..16] dB</span><br><span style="color: hsl(0, 100%, 40%);">-(bts=0,trx=0,ts=0,ss=0) Raising MS power control level 10 (10 dBm) => 9 (12 dBm): ms-pwr-lvl[curr 9, max 2], RSSI[curr -78, avg -78, thresh -80..-73] dBm, C/I[curr 14, avg 14, thresh 12..16] dB</span><br><span style="color: hsl(0, 100%, 40%);">-(bts=0,trx=0,ts=0,ss=0) Lowering MS power control level 9 (12 dBm) => 10 (10 dBm): ms-pwr-lvl[curr 10, max 2], RSSI[curr -78, avg -78, thresh -80..-73] dBm, C/I[curr 14, avg 14, thresh 12..16] dB</span><br><span style="color: hsl(0, 100%, 40%);">-(bts=0,trx=0,ts=0,ss=0) Raising MS power control level 10 (10 dBm) => 9 (12 dBm): ms-pwr-lvl[curr 9, max 2], RSSI[curr -78, avg -78, thresh -80..-73] dBm, C/I[curr 14, avg 14, thresh 12..16] dB</span><br><span style="color: hsl(0, 100%, 40%);">-(bts=0,trx=0,ts=0,ss=0) Lowering MS power control level 9 (12 dBm) => 10 (10 dBm): ms-pwr-lvl[curr 10, max 2], RSSI[curr -78, avg -78, thresh -80..-73] dBm, C/I[curr 14, avg 14, thresh 12..16] dB</span><br><span style="color: hsl(0, 100%, 40%);">-(bts=0,trx=0,ts=0,ss=0) Raising MS power control level 10 (10 dBm) => 9 (12 dBm): ms-pwr-lvl[curr 9, max 2], RSSI[curr -78, avg -78, thresh -80..-73] dBm, C/I[curr 14, avg 14, thresh 12..16] dB</span><br><span style="color: hsl(120, 100%, 40%);">+(bts=0,trx=0,ts=0,ss=0) Ignoring MS power control level 10 (10 dBm) => 9 (12 dBm): ms-pwr-lvl[curr 9, max 2], RSSI[curr -78, avg -78, thresh -80..-73] dBm, C/I[curr 14, avg 14, thresh 12..16] dB</span><br><span style="color: hsl(120, 100%, 40%);">+(bts=0,trx=0,ts=0,ss=0) Keeping MS power at control level 10 (10 dBm): ms-pwr-lvl[curr 10, max 2], RSSI[curr -78, avg -78, thresh -80..-73] dBm, C/I[curr 14, avg 14, thresh 12..16] dB</span><br><span style="color: hsl(120, 100%, 40%);">+(bts=0,trx=0,ts=0,ss=0) Ignoring MS power control level 10 (10 dBm) => 9 (12 dBm): ms-pwr-lvl[curr 9, max 2], RSSI[curr -78, avg -78, thresh -80..-73] dBm, C/I[curr 14, avg 14, thresh 12..16] dB</span><br><span style="color: hsl(120, 100%, 40%);">+(bts=0,trx=0,ts=0,ss=0) Keeping MS power at control level 10 (10 dBm): ms-pwr-lvl[curr 10, max 2], RSSI[curr -78, avg -78, thresh -80..-73] dBm, C/I[curr 14, avg 14, thresh 12..16] dB</span><br><span style="color: hsl(120, 100%, 40%);">+(bts=0,trx=0,ts=0,ss=0) Ignoring MS power control level 10 (10 dBm) => 9 (12 dBm): ms-pwr-lvl[curr 9, max 2], RSSI[curr -78, avg -78, thresh -80..-73] dBm, C/I[curr 14, avg 14, thresh 12..16] dB</span><br><span>diff --git a/tests/power/ms_power_loop_test.ok b/tests/power/ms_power_loop_test.ok</span><br><span>index 4dc01e4..2bb780d 100644</span><br><span>--- a/tests/power/ms_power_loop_test.ok</span><br><span>+++ b/tests/power/ms_power_loop_test.ok</span><br><span>@@ -166,14 +166,14 @@</span><br><span> MS current power 13 -> 14 (expected 14)</span><br><span> </span><br><span> Starting test case 'test_good_threshold_convergence'</span><br><span style="color: hsl(0, 100%, 40%);">-lchan_ms_pwr_ctrl(RxLvl=-78 dBm) returns 1 (expected 1)</span><br><span style="color: hsl(0, 100%, 40%);">- MS current power 9 -> 9 (expected 9)</span><br><span style="color: hsl(0, 100%, 40%);">-lchan_ms_pwr_ctrl(RxLvl=-78 dBm) returns 1 (expected 1)</span><br><span style="color: hsl(120, 100%, 40%);">+lchan_ms_pwr_ctrl(RxLvl=-78 dBm) returns 0 (expected 1)</span><br><span style="color: hsl(120, 100%, 40%);">+ MS current power 9 -> 10 (expected 10)</span><br><span style="color: hsl(120, 100%, 40%);">+lchan_ms_pwr_ctrl(RxLvl=-78 dBm) returns 0 (expected 0)</span><br><span> MS current power 10 -> 10 (expected 10)</span><br><span style="color: hsl(0, 100%, 40%);">-lchan_ms_pwr_ctrl(RxLvl=-78 dBm) returns 1 (expected 1)</span><br><span style="color: hsl(0, 100%, 40%);">- MS current power 9 -> 9 (expected 9)</span><br><span style="color: hsl(0, 100%, 40%);">-lchan_ms_pwr_ctrl(RxLvl=-78 dBm) returns 1 (expected 1)</span><br><span style="color: hsl(120, 100%, 40%);">+lchan_ms_pwr_ctrl(RxLvl=-78 dBm) returns 0 (expected 0)</span><br><span style="color: hsl(120, 100%, 40%);">+ MS current power 9 -> 10 (expected 10)</span><br><span style="color: hsl(120, 100%, 40%);">+lchan_ms_pwr_ctrl(RxLvl=-78 dBm) returns 0 (expected 0)</span><br><span> MS current power 10 -> 10 (expected 10)</span><br><span style="color: hsl(0, 100%, 40%);">-lchan_ms_pwr_ctrl(RxLvl=-78 dBm) returns 1 (expected 1)</span><br><span style="color: hsl(0, 100%, 40%);">- MS current power 9 -> 9 (expected 9)</span><br><span style="color: hsl(120, 100%, 40%);">+lchan_ms_pwr_ctrl(RxLvl=-78 dBm) returns 0 (expected 0)</span><br><span style="color: hsl(120, 100%, 40%);">+ MS current power 9 -> 10 (expected 10)</span><br><span> Power loop test OK</span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/c/osmo-bts/+/25503">change 25503</a>. 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<div style="display:none"> Gerrit-Project: osmo-bts </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-Change-Id: Ib33a94eba92004f9327c91e020a506dfa9a957c3 </div>
<div style="display:none"> Gerrit-Change-Number: 25503 </div>
<div style="display:none"> Gerrit-PatchSet: 1 </div>
<div style="display:none"> Gerrit-Owner: pespin <pespin@sysmocom.de> </div>
<div style="display:none"> Gerrit-MessageType: newchange </div>