Apply 5GHz band preference only when comparing configurations on different bands
Bug:18589301
Change-Id: I0093620c859940d993c9ea60d9d6cdc86bb2fa58
diff --git a/service/java/com/android/server/wifi/WifiAutoJoinController.java b/service/java/com/android/server/wifi/WifiAutoJoinController.java
index 596a61d..e30b1c7 100644
--- a/service/java/com/android/server/wifi/WifiAutoJoinController.java
+++ b/service/java/com/android/server/wifi/WifiAutoJoinController.java
@@ -584,30 +584,75 @@
}
}
+ int compareWifiConfigurationsFromVisibility(WifiConfiguration a, int aRssiBoost,
+ WifiConfiguration b, int bRssiBoost) {
- int getScoreFromVisibility(WifiConfiguration.Visibility visibility, int rssiBoost, String dbg) {
- int rssiBoost5 = 0;
- int score = 0;
+ int aRssiBoost5 = 0; // 5GHz RSSI boost to apply for purpose band selection (5GHz pref)
+ int bRssiBoost5 = 0; // 5GHz RSSI boost to apply for purpose band selection (5GHz pref)
+
+ int aScore = 0;
+ int bScore = 0;
+
+ boolean aPrefers5GHz = false;
+ boolean bPrefers5GHz = false;
/**
- * Boost RSSI value of 5GHz bands iff the base value is better than threshold
+ * Calculate a boost to apply to RSSI value of configuration we want to join on 5GHz:
+ * Boost RSSI value of 5GHz bands iff the base value is better than threshold,
+ * penalize the RSSI value of 5GHz band iff the base value is lower than threshold
* This implements band preference where we prefer 5GHz if RSSI5 is good enough, whereas
* we prefer 2.4GHz otherwise.
- * Note that 2.4GHz doesn't need a boost since at equal power the RSSI is typically
- * at least 6-10 dB higher
*/
- rssiBoost5 = rssiBoostFrom5GHzRssi(visibility.rssi5, dbg+"->");
+ aRssiBoost5 = rssiBoostFrom5GHzRssi(a.visibility.rssi5, a.configKey() + "->");
+ bRssiBoost5 = rssiBoostFrom5GHzRssi(b.visibility.rssi5, b.configKey() + "->");
- // Select which band to use so as to score a
- if (visibility.rssi5 + rssiBoost5 > visibility.rssi24) {
+ // Select which band to use for a
+ if (a.visibility.rssi5 + aRssiBoost5 > b.visibility.rssi24) {
// Prefer a's 5GHz
- score = visibility.rssi5 + rssiBoost5 + rssiBoost;
- } else {
- // Prefer a's 2.4GHz
- score = visibility.rssi24 + rssiBoost;
+ aPrefers5GHz = true;
}
- return score;
+ // Select which band to use for b
+ if (b.visibility.rssi5 + bRssiBoost5 > b.visibility.rssi24) {
+ // Prefer b's 5GHz
+ bPrefers5GHz = true;
+ }
+
+ if (aPrefers5GHz) {
+ if (bPrefers5GHz) {
+ // If both a and b are on 5GHz then we don't apply the 5GHz RSSI boost to either
+ // one, but directly compare the RSSI values, this improves stability,
+ // since the 5GHz RSSI boost can introduce large fluctuations
+ aScore = a.visibility.rssi5 + aRssiBoost;
+ } else {
+ // If only a is on 5GHz, then apply the 5GHz preference boost to a
+ aScore = a.visibility.rssi5 + aRssiBoost + aRssiBoost5;
+ }
+ } else {
+ aScore = a.visibility.rssi24 + aRssiBoost;
+ }
+
+ if (bPrefers5GHz) {
+ if (aPrefers5GHz) {
+ // If both a and b are on 5GHz then we don't apply the 5GHz RSSI boost to either
+ // one, but directly compare the RSSI values, this improves stability,
+ // since the 5GHz RSSI boost can introduce large fluctuations
+ bScore = b.visibility.rssi5 + bRssiBoost;
+ } else {
+ // If only b is on 5GHz, then apply the 5GHz preference boost to b
+ bScore = b.visibility.rssi5 + bRssiBoost + bRssiBoost5;
+ }
+ } else {
+ bScore = b.visibility.rssi24 + bRssiBoost;
+ }
+ if (VDBG) {
+ logDbg(" " + a.configKey() + " is5=" + aPrefers5GHz + " score=" + aScore
+ + b.configKey() + " is5=" + bPrefers5GHz + " score=" + bScore);
+ }
+ // Compare a and b
+ // If a score is higher then a > b and the order is descending (negative)
+ // If b score is higher then a < b and the order is ascending (positive)
+ return bScore - aScore;
}
// Compare WifiConfiguration by RSSI, and return a comparison value in the range [-50, +50]
@@ -658,13 +703,7 @@
);
}
- scoreA = getScoreFromVisibility(astatus, aRssiBoost, a.configKey());
- scoreB = getScoreFromVisibility(bstatus, bRssiBoost, b.configKey());
-
- // Compare a and b
- // If a score is higher then a > b and the order is descending (negative)
- // If b score is higher then a < b and the order is ascending (positive)
- order = scoreB - scoreA;
+ order = compareWifiConfigurationsFromVisibility(a, aRssiBoost, b, bRssiBoost);
// Normalize the order to [-50, +50]
if (order > 50) order = 50;
@@ -682,13 +721,11 @@
+ "," + a.visibility.rssi5
+ ") num=(" + a.visibility.num24
+ "," + a.visibility.num5 + ")"
- + " scorea=" + scoreA
+ prefer + b.configKey()
+ " rssi=(" + b.visibility.rssi24
+ "," + b.visibility.rssi5
+ ") num=(" + b.visibility.num24
+ "," + b.visibility.num5 + ")"
- + " scoreb=" + scoreB
+ " -> " + order);
}
@@ -895,8 +932,7 @@
int boost = mWifiConfigStore.bandPreferenceBoostFactor5
*(rssi - mWifiConfigStore.bandPreferenceBoostThreshold5);
if (boost > 50) {
- // 50 dB boost is set so as to overcome the hysteresis of +20 plus a difference of
- // 25 dB between 2.4 and 5GHz band. This allows jumping from 2.4 to 5GHz
+ // 50 dB boost allows jumping from 2.4 to 5GHz
// consistently
boost = 50;
}
