Bug fix channel utilization during high traffic

In some wifi hal implmentations, ccaBusyTime includes the device's own packet Rx time which results in high channel utilization during full-buffer downlink throughput test. The fix is to add config_wifiChannelUtilizationOverridingEnabled to allow OEM to use fixed band-dependent values. These band-dependent values are programmable through overlay.

Test: atest com.android.server.wifi
Test: manually check reported cca level during iperf downlink and uplink test
Bug: 159866355
Change-Id: If8432929f767ceaf6f18a7d269636dcaf909f33a
Merged-In: I6e131f149d242e5dbf0b8b0087303e85ed428f9f

4 files changed, 40 insertions, 4 deletions

diff --git a/service/java/com/android/server/wifi/WifiChannelUtilization.java b/service/java/com/android/server/wifi/WifiChannelUtilization.java
index 906e2d04c..5e8cde61d 100644
--- a/service/java/com/android/server/wifi/WifiChannelUtilization.java
+++ b/service/java/com/android/server/wifi/WifiChannelUtilization.java
@@ -19,6 +19,8 @@ package com.android.server.wifi;
 import static android.net.wifi.WifiManager.DEVICE_MOBILITY_STATE_STATIONARY;
 import static android.net.wifi.WifiManager.DEVICE_MOBILITY_STATE_UNKNOWN;
 
+import android.content.Context;
+import android.net.wifi.ScanResult;
 import android.net.wifi.WifiManager.DeviceMobilityState;
 import android.util.Log;
 import android.util.SparseArray;
@@ -27,6 +29,7 @@ import android.util.SparseIntArray;
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.server.wifi.WifiLinkLayerStats.ChannelStats;
 import com.android.server.wifi.util.InformationElementUtil.BssLoad;
+import com.android.wifi.resources.R;
 
 import java.util.ArrayDeque;
 import java.util.Iterator;
@@ -60,6 +63,7 @@ public class WifiChannelUtilization {
     @VisibleForTesting
     static final int CHANNEL_STATS_CACHE_SIZE = 5;
     private final Clock mClock;
+    private final Context mContext;
     private @DeviceMobilityState int mDeviceMobilityState = DEVICE_MOBILITY_STATE_UNKNOWN;
     private int mCacheUpdateIntervalMinMs = DEFAULT_CACHE_UPDATE_INTERVAL_MIN_MS;
 
@@ -72,7 +76,8 @@ public class WifiChannelUtilization {
     private long mLastChannelStatsMapTimeStamp;
     private int mLastChannelStatsMapMobilityState;
 
-    WifiChannelUtilization(Clock clock) {
+    WifiChannelUtilization(Clock clock, Context context) {
+        mContext = context;
         mClock = clock;
     }
 
@@ -85,7 +90,7 @@ public class WifiChannelUtilization {
     }
 
     /**
-     * Initialize internal variables and status after wifi is enabled
+     * (Re)initialize internal variables and status
      * @param wifiLinkLayerStats The latest wifi link layer stats
      */
     public void init(WifiLinkLayerStats wifiLinkLayerStats) {
@@ -120,6 +125,19 @@ public class WifiChannelUtilization {
      * @return Utilization ratio value if it is available; BssLoad.INVALID otherwise
      */
     public int getUtilizationRatio(int frequency) {
+        if (mContext.getResources().getBoolean(
+                R.bool.config_wifiChannelUtilizationOverrideEnabled)) {
+            if (ScanResult.is24GHz(frequency)) {
+                return mContext.getResources().getInteger(
+                        R.integer.config_wifiChannelUtilizationOverride2g);
+            }
+            if (ScanResult.is5GHz(frequency)) {
+                return mContext.getResources().getInteger(
+                        R.integer.config_wifiChannelUtilizationOverride5g);
+            }
+            return mContext.getResources().getInteger(
+                        R.integer.config_wifiChannelUtilizationOverride6g);
+        }
         return mChannelUtilizationMap.get(frequency, BssLoad.INVALID);
     }
 
@@ -153,6 +171,11 @@ public class WifiChannelUtilization {
      */
     public void refreshChannelStatsAndChannelUtilization(WifiLinkLayerStats wifiLinkLayerStats,
             int frequency) {
+        if (mContext.getResources().getBoolean(
+                R.bool.config_wifiChannelUtilizationOverrideEnabled)) {
+            return;
+        }
+
         if (wifiLinkLayerStats == null) {
             return;
         }
diff --git a/service/java/com/android/server/wifi/WifiInjector.java b/service/java/com/android/server/wifi/WifiInjector.java
index 8f6465b00..b9aa0521f 100644
--- a/service/java/com/android/server/wifi/WifiInjector.java
+++ b/service/java/com/android/server/wifi/WifiInjector.java
@@ -329,7 +329,7 @@ public class WifiInjector {
         mWifiDiagnostics = new WifiDiagnostics(
                 mContext, this, mWifiNative, mBuildProperties,
                 new LastMileLogger(this), mClock);
-        mWifiChannelUtilizationConnected = new WifiChannelUtilization(mClock);
+        mWifiChannelUtilizationConnected = new WifiChannelUtilization(mClock, mContext);
         mWifiDataStall = new WifiDataStall(mFrameworkFacade, mWifiMetrics, mContext,
                 mDeviceConfigFacade, mWifiChannelUtilizationConnected, mClock, wifiHandler,
                 mThroughputPredictor);
@@ -617,7 +617,7 @@ public class WifiInjector {
         mBssidBlocklistMonitor = new BssidBlocklistMonitor(mContext, mWifiConnectivityHelper,
                 mWifiLastResortWatchdog, mClock, mConnectivityLocalLog, mWifiScoreCard);
         mWifiMetrics.setBssidBlocklistMonitor(mBssidBlocklistMonitor);
-        mWifiChannelUtilizationScan = new WifiChannelUtilization(mClock);
+        mWifiChannelUtilizationScan = new WifiChannelUtilization(mClock, mContext);
         return new WifiConnectivityManager(mContext, getScoringParams(),
                 clientModeImpl, this,
                 mWifiConfigManager, mWifiNetworkSuggestionsManager, clientModeImpl.getWifiInfo(),
diff --git a/service/res/values/config.xml b/service/res/values/config.xml
index 4ea23adc0..cc80f608c 100644
--- a/service/res/values/config.xml
+++ b/service/res/values/config.xml
@@ -422,6 +422,15 @@
     <!-- Integer indicating the RSSI and link layer stats polling interval in milliseconds when device is connected and screen is on -->
     <integer translatable="false" name="config_wifiPollRssiIntervalMilliseconds">3000</integer>
 
+    <!-- Override channel utilization estimation with fixed value -->
+    <bool translatable="false" name="config_wifiChannelUtilizationOverrideEnabled">true</bool>
+    <!-- Integer values represent the channel utilization in different RF bands when
+          config_wifiChannelUtilizationOverridingEnabled is true.
+         They should be set to [0, 255] corresponding to utilization ratio between 0 and 1 -->
+    <integer translatable="false" name="config_wifiChannelUtilizationOverride2g">80</integer>
+    <integer translatable="false" name="config_wifiChannelUtilizationOverride5g">15</integer>
+    <integer translatable="false" name="config_wifiChannelUtilizationOverride6g">10</integer>
+
     <!-- Enable WPA2 to WPA3 auto-upgrade -->
     <bool translatable="false" name="config_wifiSaeUpgradeEnabled">true</bool>
 
diff --git a/service/res/values/overlayable.xml b/service/res/values/overlayable.xml
index b02eb9e77..a4b7011b0 100644
--- a/service/res/values/overlayable.xml
+++ b/service/res/values/overlayable.xml
@@ -132,6 +132,10 @@
           <item type="integer" name="config_wifiHighMovementNetworkSelectionOptimizationRssiDelta" />
           <item type="integer" name="config_wifiRttBackgroundExecGapMs" />
           <item type="integer" name="config_wifiPollRssiIntervalMilliseconds" />
+          <item type="bool" name="config_wifiChannelUtilizationOverrideEnabled" />
+          <item type="integer" name="config_wifiChannelUtilizationOverride2g" />
+          <item type="integer" name="config_wifiChannelUtilizationOverride5g" />
+          <item type="integer" name="config_wifiChannelUtilizationOverride6g" />
           <item type="bool" name="config_wifiSaeUpgradeEnabled" />
           <item type="bool" name="config_wifiSaeUpgradeOffloadEnabled" />
           <item type="integer" name="config_wifiMaxNativeFailureSelfRecoveryPerHour" />