cpich power

[ergin]

hi everyone,

ı want to ask that what is the benefit of decreasing or increasing the cpich power? what will happen when we increase it and what will happen when we decrease it?

thanks for your ideas

[fantominox]

Hi Ergin,
simply increase of CPICH power means increase of cell coverage.
I we have coverage gaps thats OK. We can make more users happy but if it is only action in existing network with continuous coverage, it can have significant impact on network.
Lets assume the cell is one among many cells. Increasing CPICH power without tilt change, we increase SHO area -> SHO Overhead, need create more ADJC either cause drops because of missing neighbours, generate unmonitored sets, increase pilot pollution, UL congestion, decrease available power for services (i.e HSDPA) causing congestion because increasing pilot power we increase power destinated for common channels too.
Decreasing pilot power we can cause coverage gaps, generate many IRAT HOs, but we have more power for services, less pollution etc
Such change you should do carefully, watching pm counters, KPIs - if you know your network topology it will not be problem to optimize CPICH power


BR
Fantominox

[lihanbok]

Add more information about CPICH Power:
Frequently, operators set different pilot powers across the network to mitigate RF issues like pilot pollution. The disadvantage is that artificial link imbalance scenarios are created, resulting in loss in uplink capacity. In HSDPA, the impact can be particularly severe since the stronges t uplink cell is power controlled but may not be the uplink cell that carries the HS control channel.
the setting of the CPICH transmit power determines the Ec/No value observed in a cell. (qualcomm book reference)
BR,
Lihanbok.

[tremalnike]

In common case, CPICH power must be -10dB from total power in cell. When decrease it, you'll have more capacity and lower serving zone. It's quite risky to increase it - you'll increase serving zone, but capacity decrease exponential and need to optimize all things in posts above (in order to reduce interference problems) + admission control.

Look http://www.finetopix.com/showthread....ht=cpich+power for more info

[sedicla]

Hello, my advice to you is make a simulation in Attol or Planet before making any changes on the CPICH otherwise the Network may face lots of problems.
Gaps in coverage, number of users in cell and much more.

[ergin]

thanks all for your answers.they are very informative for me..