The truth about your reception (is it as bad as you think?)

[pc747]

Paul_guyver posted this on our sister site: Galaxynexusforum.com and I believe this needs to be posted here.

HERE is another great explanation about our signal.

Originally posted here: http://rootzwiki.com..._30#entry692912

I will summarize why your signal "sucks" compared to other phones. This all based on facts--not guesses, speculation, or tests that depend on factors one cannot control.


ALL other LTE phones (excluding the Nexus) are reporting the RSSI of the cdma 1x signal in android 2.3, NOT the LTE signal. Android 2.3 was not capable of properly reporting the LTE signal and support was added for it in ICS. The Nexus also uses RSRP to determine your signal. RSRP has a huge difference to RSSI (for example):

RSSI = -79 dBm, RSRP = -93 dBm

This is why a Razr or Rezound will show -79 dBm in the same spot a GNex will display -93 dBm. Go find someone with an ICS leak of one of those and check their signal next to a Nexus. Unless the OEMs kept doing what they were doing before (which sadly they might), they should show the signal to be nearly the same.

Also, the higher your ASU under settings the better. ASU or "Arbitrary Strength Unit" is an integer value proportional to the Reference Signal Received Power (RSRP) measured by the mobile phone. Basically the higher the number for ASU, the less interference you have between you and the towers. It varies by your current type of connection, but ASU a number in the range of 0 to 99 (99 means you basically have no signal [unknown] and closer to 0 means it's also bad).

Your ASU on LTE is basically your current signal + 140. So if you have a signal of -93, then your LTE based ASU is (-93 + 140 = 47). See picture below for example:

Click here to view the original image of 720x1280px.


Technically, it'll never be 98 as it hits a ceiling of 97 if you were somehow able to get a signal of -43db (-43 + 140 = 97). If your signal is somehow worse than -140, then it will report zero, but that should also not be possible.

It's a little more complicated for CDMA ASU. On CDMA, it's some power of 2 up to 16 (1, 2, 4, 8, 16) with 16 being the best or 99 if it's unknown. It's also measured by not only your signal in db, but also by your your signal to noise ratio which is not shown to you.

↑↑↑ Source for that was SignalStrength.java under getLteAsuLevel() ↑↑↑


So, unless your data connection is dropping out constantly, it's just fine and not as bad as you think.

Before you start comparing your signal to other phones not on ICS, at least read this and look at this link to the Android source for ICS:

Quote
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.


↑↑↑ Android ICS source even says it uses the RSRP for LTE. ↑↑↑

↓↓↓ THEN....if you look down at some of the code you see things like ↓↓↓:


/**
* Get the CDMA RSSI value in dBm
*/
publicint getCdmaDbm(){
returnthis.mCdmaDbm;
}
/**
* Get the EVDO RSSI value in dBm
*/
publicint getEvdoDbm(){
returnthis.mEvdoDbm;
}
↑↑ Which is what CDMA phones were using before ICS. ↑↑

If one is still in disbelief, then you can go back and look at the Android source for SignalStrength.javaback in say like 2009/2010 and note that there is no mention of RSRP anywhere because it was not used yet (only mentions of RSSI are there).



Still don't believe me? Well go compile the source and change the following method in SignalStrength.java to return the cdma signal strength instead:



/**
* Get LTE as dBm
*
* @hide
*/
publicint getLteDbm()
{
// return cdma signal being used instead (i.e. if evdo is -120db it's not being used, so look for which is closer to zero)
returnthis.mCdmaDbm >this.mEvdoDbm ?this.mCdmaDbm :this.mEvdoDbm;
// commented out below
// return mLteRsrp;
}
And then watch your signal get "better."


Rythmyc, on 19 May 2012 - 02:21 AM, said:
It is upsetting my wife's Charge gets a much better signal than my Nexus sitting right next to it knowing it has the same radios.



↑ It's not really "better." It's (the Charge) just measuring something different (the RSSI) to obtain the signal which isn't even related to LTE. If you changed the above, the signal would probably be nearly the same. From my testing, my RSSI is nearly the same as what I got at my current location on my Thunderbolt (which everyone claims has amazingly better radios and Qualcomm chipset).

Definitions:

RSRP:

Reference signal received power (RSRP), is defined as the linear average over the power contributions in Watts of the resource elements that carry cell-specific reference signals within the considered measurement frequency bandwidth. Used to measure the signal of your LTE (GSM/4g) connection.

RSSI:

Received Signal Strength Indicator (RSSI), is the linear average of the total received power in Watts. This is used to measure the db signal for CDMA (3g/2g [2g being your 1x and voice]) signals.

RSRQ (the overall quality of your signal in general):

Reference Signal Received Quality (RSRQ) is defined for Verizon as 17 * (RSRP signal / RSSI signal)



Additional Info/Further Reading:

http://docs.google.c...28qjNF66uPBYmfA



https://docs.google....fUvgTfFjRQ-4Mhw


Quote
"Why does my Nexus not hand off exactly the same as <insert proprietary android os based phone here>?"


Because it goes back to what I already mentioned in that other OEMs don't measure the LTE signal with the same metrics as they do on the Nexus (it was only added to the Android source with ICS and before then each carrier just "rolled their own" thing probably using the RSSI of the LTE signal to handle when to hand off) so the phone thinks the LTE signal is also better than it actually is and so it's staying on what is really a *worse* LTE signal when it should be handing off to a better CDMA/3g signal.


You can find out the RSSI of the LTE connection by using an app like rf signal tracker. In the times I have compared, the RSRP for LTE (what you see under status in the settings area of the phone itself) is always far worse than the RSSI in the rf signal app and it's generally also better than the 3g RSSI you'll see. RSSI is an okay metric to handle 3g/cdma, but it's not nearly as good for LTE as RSRP is. OEMs are still using it other than for the Nexus and it's those other phones hold LTE longer than they should in many cases as that was the metric they had to go on with Gingerbread and before RSRP became the standard measure of LTE signal for Android.


It's actually a good thing it's handing it off and staying on 3g for most use cases. If it were me, I'd be more upset with it handing off and switching back constantly instead of staying on one or the other as that also drains battery. If you want to force it to stay on LTE, dial *#*#4636#*#* and tell it to stay on it. It may interfere with calls though and drain more battery, so just as a fair warning.

*You're welcomed to question anything I stated above in the discussion as long as you do it in a constructive way that's not flaming. BUT if you do, please provide FACTUAL information from credible sources. That means things like "Well, I compared the Nexus to X phone and it didn't look as good" do not count as factual. Non factual posts will most likely be considered trolling or flamebait that's trying to derail this into another one of the typical "signal quality" discussions we have all seen before and be subject to removal (nothing personal, it's just you have to spend time on something if you want to disagree with it in public).


But...if one wants to believe whatever voodoo makes one signal "worse" than another then I guess that's everyone's right. I give up trying to convince

The Official: I am having reception issues thread - Page 11

[pc747]

The above statement is not to say those with actual connection issues are not having problems because it very well could be a bad phone. But I look at my lte numbers and compare it to the rezound and razr and been frustrated. Now it seems that I was just misinformed. So if I am getting a good signal and my data is not being interrupted then I am not gonna fret.

[WookieClaws]

Great post, thanks. I've always though that the GNEX's reception scaling might be a bit off simply because there have been places where I have 0 bars but still have LTE and it doesn't switch over to 3G. I quit worrying about bars, but that explanation helps me understand much better what's going on.

[pc747]

Want to give credit to the orginal posters real quick:

This is why your Verizon Nexus signal "sucks" - Galaxy Nexus - RootzWiki

Soo I went to Verizon today... - Galaxy Nexus - RootzWiki - Page 4

RSRP and RSRQ Measurement in LTE | Wireless Wisdom

If I missed any one let me know.

[MyDroid23]

Rumour is the much anticipated 4.0.4 will start rolling out to the mass 5/22 which would be tomorrow. I got my fingers crossed.

[GalaxyFlatulence]

Duh. Its just forum people that keep ignorently blaming all their lte devices

[DesktopDevin]

Duh. Its just forum people that keep ignorently blaming all their lte devices

Try learning how to spell ignorantly or how to use spell check before you start calling other users ignorant.

The problems that myself and other users have with reception are not imagined.

I for one can be standing right next to another verizon 4g lte customer and while their phone can connect and stream video flawlessly this pos gnex is still trying to connect to the stream.

It's not about any perceived value on a meter. It is about performance.....which really sucks!!!!!

Sent from my Galaxy Nexus using Droid Forums

[Crankintopwater69]

Try learning how to spell ignorantly or how to use spell check before you start calling other users ignorant.

The problems that myself and other users have with reception are not imagined.

I for one can be standing right next to another verizon 4g lte customer and while their phone can connect and stream video flawlessly this pos gnex is still trying to connect to the stream.

It's not about any perceived value on a meter. It is about performance.....which really sucks!!!!!

Sent from my Galaxy Nexus using Droid Forums

[MyDroid23]

We all paid a pretty penny for the G-Nex. And it should perform like a champ on the best most reliable network with ICS!!!

[Crankintopwater69]

We all paid a pretty penny for the G-Nex. And it should perform like a champ on the best most reliable network with ICS!!!

Agreed Sir.At 300 a pop,she should be as smooth as the Iphone.