WLAN and GSM Strenght value

[omarfr]

Hello,

I need to know what are the meassures for WLAN and GSM strength values in the following situations:

1. For WLAN I am using smth like this:

CWlanScanInfo *iScanInfo;
//init iScanInfo, etc...
TInt8 rxLevel = iScanInfo->RXLevel();
...

I get different numbers for rxLevel, usually between 80 and 99.
What does this value represent? I have no idea how to use this information. In the header file it says only this:

        /**
        * Return RX level of the BSS.
        * @return RX level.
        */
        virtual TUint8 RXLevel() const = 0;

2. For GSM strenght value I am using CTelephony like this:

CTelephony* iTelephony;
CTelephony::TSignalStrengthV1 iGSMPwr;   //For signal strength
CTelephony::TSignalStrengthV1Pckg iGSMPwrPkg;
//init everything, etc...
iTelephony->GetSignalStrength(iStatus, iGSMPwrPkg);
//signal value is in iGSMPwr.iSignalStrength
...

The information on the header file is also very poor:

class TSignalStrengthV1 : public TEtelISVType
	/**
	Defines the phone's current signal strength.
	*/
		{
	public:
		IMPORT_C TSignalStrengthV1();
	public:
		/**
		The value of signal strength.
		*/
		TInt32 iSignalStrength;
		/**
		The absolute number of signal "bars" that the phone should display.
		*/
		TInt8 iBar;
		};

Again I don't know what to do with the iSignalStrength value, how to interpret it. I've only noticed that for a big value (eg. 99) I have only 1 iBar as for a smaller value (eg. 88) I have maximum nr. of bars (7).

I can assume it is a dB value (smth like 200(lgV / V)) but I am not sure, normally it should be expressed like P = 10lg(P1/P0), where P1 is the actual strength and P0 is a reference strength so if we know P0 we can compute P1 from P.

Please help on this.

Thanks,
Omar

[omarfr]

After a few comments, I think the value is a dBm value expressed in negative.

Read here:
http://en.wikipedia.org/wiki/DBm
-70 dBm = 100 pW Typical range (−60 to −80 dBm) of wireless (802.11x) received signal power over a network

So if you get x = 70 it means -70dBm.

To get actual power -> P = 10^(-x/10)W.

Maybe I'm wrong... I wait for replies

Omar