- This topic has 5 replies, 1 voice, and was last updated 14 years, 11 months ago by Javed Shaikh.
5th September 2007 at 07:23 #49121evegnius_bGuest
I need some consulting.
We have problems with interference at GSM band.
There was an idea to use 2 antennas at different heights for 1 cell. Higher antenna for coverage, other for capacity.
No any additional features to control traffic – only handover parameters.
Can you give some ideas of advantages and disadvantages of that configuration?
Anyone realised that in a live network?
Thanks5th September 2007 at 08:09 #49122PixGuest
It is possible to have such configuration. The only impact you have is a loss of TX POWER. Indeed, you must use a power splitter to split the signals between antenna 1 and antenna 2. That leads to a 3dB loss !!
It’s quite big, especially considering that one antenna should be for coverage only !
Best solution : split your bts in two sectors.5th September 2007 at 08:43 #49123asoGuest
If you Use the same Band for two antenna it will make you problem for example is the height is not the same there will link imbalance and cause performance of the cell bad .
But if you use two different band for expamle you can use 900 for coverage and 1800 for capacity5th September 2007 at 10:13 #49124evgenius_bGuest
Thanx for your answers my friends.
I forgot about power reducing. Thanks.
You mean it`s better to use 2 different cells istead one, don`t you?
(higher cell for coverage the last one for capacity)
We already use GSM1800 everywhere for capacity.
And traffic control algorithms seem very good.
But problem with GSM900 is increase with building of new sites. It`s due the lack of available ARFCN.
So the idea to add GSM900 microcell layer to reduce traffic of high cells and put as much traffic as possible to underlayer.6th September 2007 at 12:42 #49125PixGuest
Yes, i meant this : use two cells.24th September 2007 at 09:38 #49126Javed ShaikhGuest
why we placed cell site in center in hexagonal cell & why we can use hexagonal cell site instead of circular cell site.