Merge "Introduce getRssi() in CellSignalStrengthLte" am: 5bdf255e0d

am: e819bd7a1e

Change-Id: I77c5ba0bf87afde281473134a306595c052820cc

2 files changed, 46 insertions, 0 deletions

diff --git a/api/current.txt b/api/current.txt
index eb32f0600a24..c5fbe605d5ab 100755
--- a/api/current.txt
+++ b/api/current.txt
@@ -42293,6 +42293,7 @@ package android.telephony {
     method public int getLevel();
     method public int getRsrp();
     method public int getRsrq();
+    method public int getRssi();
     method public int getRssnr();
     method public int getTimingAdvance();
     method public void writeToParcel(android.os.Parcel, int);
diff --git a/telephony/java/android/telephony/CellSignalStrengthLte.java b/telephony/java/android/telephony/CellSignalStrengthLte.java
index d6856b397a00..280a8d2a0020 100644
--- a/telephony/java/android/telephony/CellSignalStrengthLte.java
+++ b/telephony/java/android/telephony/CellSignalStrengthLte.java
@@ -31,6 +31,25 @@ public final class CellSignalStrengthLte extends CellSignalStrength implements P
     private static final String LOG_TAG = "CellSignalStrengthLte";
     private static final boolean DBG = false;
 
+    /**
+     * Indicates the unknown or undetectable RSSI value in ASU.
+     *
+     * Reference: TS 27.007 8.5 - Signal quality +CSQ
+     */
+    private static final int SIGNAL_STRENGTH_LTE_RSSI_ASU_UNKNOWN = 99;
+    /**
+     * Indicates the maximum valid RSSI value in ASU.
+     *
+     * Reference: TS 27.007 8.5 - Signal quality +CSQ
+     */
+    private static final int SIGNAL_STRENGTH_LTE_RSSI_VALID_ASU_MAX_VALUE = 31;
+    /**
+     * Indicates the minimum valid RSSI value in ASU.
+     *
+     * Reference: TS 27.007 8.5 - Signal quality +CSQ
+     */
+    private static final int SIGNAL_STRENGTH_LTE_RSSI_VALID_ASU_MIN_VALUE = 0;
+
     @UnsupportedAppUsage
     private int mSignalStrength;
     @UnsupportedAppUsage
@@ -142,6 +161,19 @@ public final class CellSignalStrengthLte extends CellSignalStrength implements P
     }
 
     /**
+     * Get Received Signal Strength Indication (RSSI) in dBm
+     *
+     * The value range is [-113, -51] inclusively or {@link CellInfo#UNAVAILABLE} if unavailable.
+     *
+     * Reference: TS 27.007 8.5 Signal quality +CSQ
+     *
+     * @return the RSSI if available or {@link CellInfo#UNAVAILABLE} if unavailable.
+     */
+    public int getRssi() {
+        return convertRssiAsuToDBm(mSignalStrength);
+    }
+
+    /**
      * Get reference signal signal-to-noise ratio
      *
      * @return the RSSNR if available or
@@ -309,4 +341,17 @@ public final class CellSignalStrengthLte extends CellSignalStrength implements P
     private static void log(String s) {
         Rlog.w(LOG_TAG, s);
     }
+
+    private static int convertRssiAsuToDBm(int rssiAsu) {
+        if (rssiAsu != SIGNAL_STRENGTH_LTE_RSSI_ASU_UNKNOWN
+                && (rssiAsu < SIGNAL_STRENGTH_LTE_RSSI_VALID_ASU_MIN_VALUE
+                || rssiAsu > SIGNAL_STRENGTH_LTE_RSSI_VALID_ASU_MAX_VALUE)) {
+            Rlog.e(LOG_TAG, "convertRssiAsuToDBm: invalid RSSI in ASU=" + rssiAsu);
+            return CellInfo.UNAVAILABLE;
+        }
+        if (rssiAsu == SIGNAL_STRENGTH_LTE_RSSI_ASU_UNKNOWN) {
+            return CellInfo.UNAVAILABLE;
+        }
+        return -113 + (2 * rssiAsu);
+    }
 }