P-CPICH and overshooting

[sakibd2k]

Hi all,

I want to clear some basic concept.
What is Pilot channel and how does cell is overshooting?
In response of the answer i will ask question after that.

Thanks

[riverstreamer]

Two docs:
CPICH Power Optimization (E*******)
A thesis on UMTS Dimensioning

[Blacktiger]

@riverstreamer : Hey Can You Upload to somewhere else.

Thanks in Advance.

[gc_sw]

common pilot channel power is a downlink channel broadcast by node b's with constant power and of a known bit sequence.

[sakibd2k]

HI Riverstreamer,

I actually unable to download those doc as i dont have enough
previlege and i get this message

you do not have permission to access this page. This could be due to one of several reasons:

Your user account may not have sufficient privileges to access this page. Are you trying to edit someone else's post, access administrative features or some other privileged system?
If you are trying to post, the administrator may have disabled your account, or it may be awaiting activation.


SO what will i do to read those doc?

thanks

[coursekec]

Another great document on CPICH from E//

[sakibd2k]

" common pilot channel power is a downlink channel broadcast by node b's with constant power and of a known bit sequence"
i understand it thanks.
@gc_sw: So how will pilot pollution occur?
Is there any coverage hole thats the pollution? is that because of power is not uniform over the coverage area?

I cannot download the document yet untill i post enough . SO could have read the attached doc.

[sakibd2k]

hi ,

I just got pilot pollution related answer.
Pilot pollution is a type of co-channel interference in CDMA systems caused when the pilot code from a distant cell or base station is powerful enough to create an interference problem.

So why is that pollution is only with CDMA system?does not happen in GSM?

Thanks

[s52d]

hi ,

I just got pilot pollution related answer.
Pilot pollution is a type of co-channel interference in CDMA systems caused when the pilot code from a distant cell or base station is powerful enough to create an interference problem.

So why is that pollution is only with CDMA system?does not happen in GSM?

Thanks

Pilot pollution is if you have several (over 3) cells with simmilar signal strength - as a consequence, you have bad EcNo (your own best cell is weak - so all traffic on other cells are interferring), and a lot of unnecessary events when terminal tries to get 3 best cells into active set. It is quite likely you run out of power (drop) or you fail to change cells (drop) or your EcNo is too low (move to GSM) even if RSCP is good.

In ideal world, there is never more than 3 cells ;-). Overshooting means cell creates interference
where it should not. In order to detect, we do drive tests with PN scanner and do our analyzes.


In BSS, we try to separate BCCH on different frequencies, thus there is no interference.
Anyhow, yes we have BCCH pollution. If there are many cells, all with equall signal strength,
terminal can not pick best one - and it is quite likely to find some undefined neighbor relation and drop ;-).

Take your test phone to some high building, where you can see many BS antennas and there is no clear best server, and enjoy plenty of handovers and drops.

Worst case: take your TEMS into balloon and try making calls 800 m above big city.
You are out of main lobe for antennas close, in main lobe for far away... Pure fun!

Not many networks are optimized for interference free operation on 800 m high, so balloon pilots
prefer to use operators with low traffic and low number of base stations ;-)

BR
s52d

[banisha]

Guys, just clarify something for me. To find areas of pilot pollution I look how many scrambling codes are found in 5dB from top one Ec or from top one Ec/Io scrambling code?
So do I use Ec or Ec/Io to identify areas of pollution?