[raza]

can anyone tell me why the rxlev is in negative?

And if suppose rxlev is -60 dbm then do we address it as high rxlev or low rxlev.

[Rex]

Hi,
Negative value cause it’s less then 1 mW.

[Baig]

As far as i know about this, it is not due to absolute value of power. actually the rxlevel is calculated with referece to RSSI(Recieve Signal Strength Indicator). RSSI is a vendor based parameter. RxLevel in turn is calculated through manipulation of it. couldn’t find the exact formulation though.please share if anybody knows

[Pix]

Hi all,

RxLev is a measurement of absolute power.

If RxLev = 0 dBm it means the received level is 1mW
if Rxlev = -3dBm –> 0.5mW
RxLev = -6dBm –> 0.25mW
RxLev = -9dBm –> 0.125 mW
-12dBm –> 0.0625 mW

and so on.

a MS has a measurement range from -47dBm to -110dBm.
-47dBm : high received power
-110dBm : low received power

but the MS can hear stronger than -47dBm, it just can’t report a measurement higher than -47dBm.

RSSI is a coded value representing the RxLev. It is very simple :
-110dBm –> RSSI = 0
-109dBm –> RSSI = 1
-100dBm –> RSSI = 10
-90dBm –> RSSI = 20
-80dBm –> RSSI = 30
…

Cheers,
Pix

[Baig]

Thanx for the correction Pix

What measurement would you get if the level is less than -47. I’ve also found level less than -47 on TEMS.

[pix]

hi,

tems is not standard ms, it can display a wider range of values. however, it can report only within the -47 to -110 dBm (in the meas report, sent to bts/bsc)

if rxlev higher than -47 then the value -47 is used.
if lower than -110dBm then -110dBm is used 🙂

cheers
pix (writing with one hand… sorry for the missing caps)

[ALI SIDICK]

HI
is someone help me ,how to make process&analyse with tems investigation.and also can help me to find more experience about optimisation network.
BR//
ALI SIDICK

[Salah]

Sorry engineers but i want to ask what are the best,accepted,poor ranges of rxlev and rxqual?

[pix]

rxlev good > -75dBm
rxqual good > 4

rxlev bad < -85dBm rxqual bad < 5 cheers pix

[pix]

oops
rxqual good 0…4
rxqual bad 5…7

sorry 🙁

[NA]

The formula for W to dBm conversion is X (dBm)=10 log Y (mW)

so when we convert the smaller power as 0.3 mW
that will be written as :-

X dBm = 10 log 0.3
= 10 log 3^(-1)
= – 10 log 3
= – 10*0.477
= – 4.77 dBm

gives 0.3 mW = -4.77 dBm

so, it is clear here why -ve sign pops out to the value when we calculate the Rx level, as Rx level is always smaller, but Tx is always +ve because it is near the transmitter giving much power.

thanx

[vicky]

i think what we are receiving is the addition and subtraction of Tx power,various gains and losses encountered and when we calculate ( LB) final fig is -ve i.e. rx lev expected.

[Arif]

can anybody tell me about sudden CSBR increment on any gsm Ericsson’s cell? Parameter tuning didn’t decrease FR traffic. Is it the affect of VOIP call? As it removes automatically!

[Santos]

hello there would you please help me

I have this

14=-96dbm
15= ??

can you please show me how to calculate this

[Rex]

Hi Santos,
it’s RSSI coded value against RxLev.
RSSi ranges from 0 to 63 which is equal to range -110 dBm to -47 dBm.
So,
-110 dBm : RSSI=0
-109 dBm : RSSI=1 and so on till
.
.
-47 dBm : RSSI=63.
In your question if -96 dBm is 14 then 15 is -95 dBm.
Regards,
Rex

[Author]

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