Same (BCCH, BSIC) couple

same BCCH or adjacent BCCH will lead to very poor RF performances, whatever the BSIC value. co bcch and adj bcch should be located as far away as possible from each other.

(adj BCCH, same BSIC) will not lead to “phantom” allocation like you are seeing with (same bcch, same bsic). Because the frequencies are different.

(same BCCH, adj BSIC) might lead to some problems, because actually the BSIC is not acting as a filter. The two BCCH will understand each others Channel Requests. I might be wrong though, let’s say I’m 80% sure about that.

Regards,
Pix

what i meant was that a Channel Request message does not contain any information about the BSIC. When a MS sends a Channel Request on a certain frequency, all cells using this frequency as a BCCH can hear and decode it.
They will understand it as a valid Channel Request, whichever their BSIC.

The only constraint is that it’s on their BCCH frequency, and it reaches the BTS during the TS0. If it arrives after or before, it’s going to interfere another timeslot of the TRX.

Regards,
Pix

The BSIC is an identifier of the cell, so that MS can distinguish between two cells using the same frequencies.

About the channel request, it’s a little weird. A cell is always tagged with a certain a BSIC, so a MS is always going to send a channel request in a cell which is broadcasting a BSIC. Your situation is impossible 🙂

If a cell doesn’t have a BSIC, the world would come to an end.

Just to clarify, For cells with Same BCCH, and Same BCC part of BSIC (BSIC = NCC, BCC) the KPIs will still degrade.

This is due to the fact that BCC part is the one which is used in Access Burst. (May cause Phantom rach requests too. These requests are there as Access burst is same for Handover, RACH attempt and GPRS).

Also, Adjacent BSIC does not pose ANY problem. So Pix should be 100% sure about it 🙂 This is due to the fact that the actual sequences corresponding to the different BSICs are orthogonal.

Pix,
I have got multiple 1.5 volt battery cells that does not have a BSIC, but my world hasn’t ended 🙂

Regards,

Ali,

:-))

And yes, you are right about adj BSIC. But I was talking as :
(same BCCH, adj BSIC)

So you see, one year ago, I said that the BSIC info is not contained into the channel request. However, that is not true.. The BSIC is contained in the training sequence code located in the middle of the Access Burst. So it does act as a filter.

Conclusion : Pix is improving with time.
Like a good french wine.
Except Pix doesn’t make people sick in the morning….

🙂

Well Pix
Tell me when can I have a dinner with you? Need to quench my thirst with “Old French Wine” :-))

Regarding “ambiguous interpretations”, I am shocked how telecom experts ask each other for dinner 🙂

Well actually, I think still there might be room for improvement as whole BSIC is NOT contained in the Access burst. It is only the BCC part.

Just let me know when the French wine becomes strong enough to start making people sick 🙂