- This topic has 15 replies, 1 voice, and was last updated 7 years, 9 months ago by Fahad.
28th October 2009 at 18:22 #59356razaGuest
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.28th October 2009 at 21:23 #59357RexGuest
Negative value cause it’s less then 1 mW.29th October 2009 at 07:11 #59358BaigGuest
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 knows29th October 2009 at 11:00 #59359PixGuest
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
Pix30th October 2009 at 09:54 #59360BaigGuest
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.30th October 2009 at 12:14 #59361pixGuest
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 🙂
pix (writing with one hand… sorry for the missing caps)2nd November 2009 at 10:27 #59362ALI SIDICKGuest
is someone help me ,how to make process&analyse with tems investigation.and also can help me to find more experience about optimisation network.
ALI SIDICK25th June 2010 at 18:14 #59363SalahGuest
Sorry engineers but i want to ask what are the best,accepted,poor ranges of rxlev and rxqual?27th June 2010 at 05:06 #59364pixGuest
rxlev good > -75dBm
rxqual good > 4
rxlev bad < -85dBm rxqual bad < 5 cheers pix27th June 2010 at 05:58 #59365pixGuest
rxqual good 0…4
rxqual bad 5…7
sorry 🙁27th June 2010 at 14:48 #59366NAGuest
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.
thanx27th June 2010 at 15:06 #59367vickyGuest
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.23rd July 2010 at 06:42 #59368ArifGuest
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!15th June 2011 at 19:10 #59369SantosGuest
hello there would you please help me
I have this
can you please show me how to calculate this15th June 2011 at 23:10 #59370RexGuest
it’s RSSI coded value against RxLev.
RSSi ranges from 0 to 63 which is equal to range -110 dBm to -47 dBm.
-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.