Use LTE SNR and RSRP to set signal level bar.

The LTE signal strength level is the smaller one
between lte rsrp level and lte snr level if both
rsrp and snr are valid.

The lte snr mapping are

  Four  bars: SNR >= 45
  Three bars: 10 <= SNR < 45
  Two   bars: -30 <= SNR < 10
  One   bars: SNR < -30
  No    bars: No Service

The invalid value of lte snr is changed to INVALID_SNR
from -1, since -1 is a valid value of lte snr.

bug:5640958
Change-Id: If26aaba0c7fcc0fee3db488b5adfa02922f06715

1 files changed, 27 insertions, 7 deletions

diff --git a/telephony/java/android/telephony/SignalStrength.java b/telephony/java/android/telephony/SignalStrength.java
index 05e198f..1a4b574 100644
--- a/telephony/java/android/telephony/SignalStrength.java
+++ b/telephony/java/android/telephony/SignalStrength.java
@@ -47,6 +47,9 @@ public class SignalStrength implements Parcelable {
         "none", "poor", "moderate", "good", "great"
     };
 
+    /** @hide */
+    public static final int INVALID_SNR = 0x7FFFFFFF;
+
     private int mGsmSignalStrength; // Valid values are (0-31, 99) as defined in TS 27.007 8.5
     private int mGsmBitErrorRate;   // bit error rate (0-7, 99) as defined in TS 27.007 8.5
     private int mCdmaDbm;   // This value is the RSSI value
@@ -96,7 +99,7 @@ public class SignalStrength implements Parcelable {
         mLteSignalStrength = -1;
         mLteRsrp = -1;
         mLteRsrq = -1;
-        mLteRssnr = -1;
+        mLteRssnr = INVALID_SNR;
         mLteCqi = -1;
         isGsm = true;
     }
@@ -136,7 +139,8 @@ public class SignalStrength implements Parcelable {
             int evdoDbm, int evdoEcio, int evdoSnr,
             boolean gsm) {
         this(gsmSignalStrength, gsmBitErrorRate, cdmaDbm, cdmaEcio,
-                evdoDbm, evdoEcio, evdoSnr, -1, -1, -1, -1, -1, gsm);
+                evdoDbm, evdoEcio, evdoSnr, -1, -1,
+                -1, INVALID_SNR, -1, gsm);
     }
 
     /**
@@ -292,7 +296,7 @@ public class SignalStrength implements Parcelable {
             if ((mLteSignalStrength == -1)
                     && (mLteRsrp == -1)
                     && (mLteRsrq == -1)
-                    && (mLteRssnr == -1)
+                    && (mLteRssnr == INVALID_SNR)
                     && (mLteCqi == -1)) {
                 level = getGsmLevel();
             } else {
@@ -327,7 +331,7 @@ public class SignalStrength implements Parcelable {
             if ((mLteSignalStrength == -1)
                     && (mLteRsrp == -1)
                     && (mLteRsrq == -1)
-                    && (mLteRssnr == -1)
+                    && (mLteRssnr == INVALID_SNR)
                     && (mLteCqi == -1)) {
                 asuLevel = getGsmAsuLevel();
             } else {
@@ -363,7 +367,7 @@ public class SignalStrength implements Parcelable {
             if ((mLteSignalStrength == -1)
                     && (mLteRsrp == -1)
                     && (mLteRsrq == -1)
-                    && (mLteRssnr == -1)
+                    && (mLteRssnr == INVALID_SNR)
                     && (mLteCqi == -1)) {
                 dBm = getGsmDbm();
             } else {
@@ -566,6 +570,7 @@ public class SignalStrength implements Parcelable {
      */
     public int getLteLevel() {
         int levelLteRsrp = 0;
+        int levelLteRssnr = 0;
 
         if (mLteRsrp == -1) levelLteRsrp = 0;
         else if (mLteRsrp >= -95) levelLteRsrp = SIGNAL_STRENGTH_GREAT;
@@ -573,8 +578,23 @@ public class SignalStrength implements Parcelable {
         else if (mLteRsrp >= -115) levelLteRsrp = SIGNAL_STRENGTH_MODERATE;
         else levelLteRsrp = SIGNAL_STRENGTH_POOR;
 
-        if (DBG) log("Lte level: "+levelLteRsrp);
-        return levelLteRsrp;
+        if (mLteRssnr == INVALID_SNR) levelLteRssnr = 0;
+        else if (mLteRssnr >= 45) levelLteRssnr = SIGNAL_STRENGTH_GREAT;
+        else if (mLteRssnr >= 10) levelLteRssnr = SIGNAL_STRENGTH_GOOD;
+        else if (mLteRssnr >= -30) levelLteRssnr = SIGNAL_STRENGTH_MODERATE;
+        else levelLteRssnr = SIGNAL_STRENGTH_POOR;
+
+        int level;
+        if (mLteRsrp == -1)
+            level = levelLteRssnr;
+        else if (mLteRssnr == INVALID_SNR)
+            level = levelLteRsrp;
+        else
+            level = (levelLteRssnr < levelLteRsrp) ? levelLteRssnr : levelLteRsrp;
+
+        if (DBG) log("Lte rsrp level: "+levelLteRsrp
+                + " snr level: " + levelLteRssnr + " level: " + level);
+        return level;
     }
 
     /**