- This topic has 5 replies, 1 voice, and was last updated 9 years, 10 months ago by franky.
13th April 2011 at 05:57 #66170MKTGuest
Heard about path imbalance. Wondering what harm it can do?
Also, how it( path imbalance) gets generated.
On the one side we have a BTS who..
is transmitting at more power…
having same path as the MS….
but the frequency is higher…
path losses will be more for the DL signal…
where as on the other side we have..
MS transmitting at low power..
and that is not even directional…
path is same though….
but the frequency is lower( UL)…
It is understood that if there was no power control the
RXLEVEL_UL will always be less than the RXLEVEL_DL. so what…as far the RXLEVEL at both the ends meeting the thresholds of receiver the needed is done.
Moreover we have PC in practice to help.
So, what is that troubles us about the path imbalance.
Regards13th April 2011 at 07:10 #66171BrotherGuest
Path imbalance means, between uplink level and downlink level there is a balance,downlink should be bigger ofcourse it is about 4-5 db acceptable ,
imbalance occurs if dl is for example 10 db higher than uplink or downlink is lesser than uplink,13th April 2011 at 08:43 #66172el mariachiGuest
path balance = uplink losses- downlink losses
idealy this is zero
for motorola :
path balance = uplink losses- downlink losses- 110
idealy = -110
accepted range +- 5 or 6 dB.
if you have a path balance problem this means maybe on UL or DL the signal doesnt reach the UE or the BTS.
which leads to drop calls and low CSSR.13th April 2011 at 09:09 #66173MKTGuest
I think the point is not understood.
What i want to say is that even if path imbalance is there BUT RXLEVEL_UL is above threshold( Receiver sensitivity) then what is the problem?13th April 2011 at 09:56 #66174frankyGuest
Well link imbalance in lots of TRXs can make the whole network topsy turvy.. 😉 It has a direct affect on RX Ul quality and RX Dl quality.13th April 2011 at 10:51 #66175frankyGuest
The idea behind path imbalance is that as you are using the same equipment and path so the losses should be same in UL as well as DL(a little lesser in DL as you said earlier). If there is a difference between these two path losses then it clearly points out that you have some hardware issues. High UL Path loss-Rx side hw issue. High DL Path loss-Tx side hw issue.
As for your question even if RXLEVEL_UL is above threshold( Receiver sensitivity) then also there is a virtual shrinkage in cell coverage due to link imbalance. This means far away calls(with lesser UL and DL powers) are deprived of good quality.