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Our network is using collacated cells with two BCCHs, one for 900 and the other for 1800. For dual band it means one single 900 BCCH is used for both the 1800 and 900 cells. So I would like to know the pros and cons of each type. and in which cases is each selected. Did any of you moved from collacated to dual band? I am waiting for ur recommendations
Also in terms of configuration, maintenance which one is better?
I’m sorry Abdel, I forgot, which vendor are you working with ?
Pros of concentric dualband cells :
– less cells in the network
– less adjacencies to define
– only one BCCH planning to perform
– 1800 BCCH TS is replaced by a TCH (+ 1 TS gain)
– easier parameters settingsCons :
– monoband 1800 MS cannot access these cells
– GPRS *might* be allowed only on the 900 TRX (vendor dependent, i suppose).
– parameters are possibly less flexible, but more complex.I designed concentric cells in malaysia, country wide, the results were great (alcatel systems). I would recommend this to anyone who
1. doesn’t care putting all the GPRS on the 900 band.
2. have a good overlap between 1800 cells
3. doesn’t mind learning about concentric parametersRegards,
PixWe are using different vendors but I am concerned to our largest city which is using a Huawei BSS. I am not sure whether their BSS can support concentric cells or not. So if it supports do you recommend to move to a concentric , because at the moment we are experiencing some cell reselection problems. Thanks
Abdel,
I gave you my opinion in the previous post. It didn’t change since then 🙂
Pix,
Thanks for your useful reply.
Okay, I got the logical part.What about the physical? Do i have to mix the 900 and 1800 TRX together in one cabinet?Do they share one abis E1. If we want to migrate to concentric cells are there any physical connections between the two 900 and 1800 BTSs.
ThanksThose are TRX from a same cell, you just have to do the same thing as you would do when using monoband TRX of a cell.. If available in Huawei, you can split these TRX onto 2 BTS’s, or collocate them in a same cabinet.
Several intracell TRX split over 2 BTS’s is done by a cable linking the two SUM cards of these BTS’s.
If the TRX are already in one cabinet, I believe you can merge the two cells into one concentric from the OMC-R directly. Zero site operation to be performed.
Little reformulation :
– parameters are possibly less flexible, but more complex.
I mean that concentric cells are little bit less flexible in terms of settings, but less complex to handle than two collocated cells.Regards,
PixTo be more clearer, I have two BTSs 900 BTS and 1800 at each site and the TRXs are already there in the cabinets. There is no any interconnection between these two BTS, therefore, can I implement concentric cells without changing any physical and do some configuration at the OMCR. I am not sure about Huawei but what about alcatel can you suddenly switch to concentric cell without doing any operation at the site if the two BTS are already in a functioning state?
ThanksAbdel :
Do you really read my answers ? :))
“Several intracell TRX split over 2 BTS’s is done by a cable linking the two SUM cards of these BTS’s.”
I mean that TRX’s over 2 BTS, but that should belong to one cell, is possible, IF you link the 2 BTS by a cable.
Pix,
Sorry, I read your answer but one question. what are SUM boards are they the TRX boards,e1,CDU..etc.Hey guys
“Dual band and Collacated Cells”
i know dual band can you give some hints about Collacated Cells, thanks in advance.Abdel,
Ok, it must be alcatel name… SUM card is the control board, that is usually linked to the BSC via the Abis interface. It contains the clock of the BTS, etc.
Mazin,
Collocated cells : one cell 900 and one cell 1800, located on the same mast, with antennas pointing in the same directions. It is two cells on one sector.
hi abdel,PIX
in my network we have the same situation as u Abdel about concentric cell
but i found one problem which is
when handover is performed from UL to OL many handover failure
i don’t know why
do u have any idea about thisnote: i am talking about Huawei’s BTS
thanks in advanceReason of handover failure from UL to OL is usually due to the fact that when MS is in UL cell it doesn’t know and can’t report the signal strength of OL subcell. BSC makes the decision based on either UL path loss or TA which may not be very accurate. Try to decrease the path loss threshold for subcell change
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