- This topic has 13 replies, 1 voice, and was last updated 13 years, 4 months ago by TNS.
28th December 2007 at 15:46 #50202HamdiGuest
I’m a BSS engineer and i’m new here. I would like to ask how to define the optimal NbExtraAbisTS in our Alcatel network. which is the appropriate method and how using the sharing factor (dynamic abis feature in B9) to adjust this parameter.
Thanks29th December 2007 at 12:20 #50203PixGuest
I’m afraid you’ll need to perform a full design study in order to determine how many TS you can/need to use as “extra TS”.
By default, you can put all remaining Abis TS for an Abis Link as “extra TS”.
The more Extra TS you put, the more users on the BTS can experience higher throughputs.
Pix4th January 2008 at 14:36 #50204FlexGuest
NbExtraAbisTS depends on the coding scheme used in a cell.10th January 2008 at 08:22 #50205HamdiGuest
Thank you for your replies. as u say pix it is more suitable to have more “extra TS”, but i think these “extra TS” will need ressources on BSC’s (affecting BSC HW load) and therefore my purpose is to have the less number of “extra TS” offering the highest throughput and for this i would like to use the sharing factor as defined in B9.so how to proceed?10th January 2008 at 10:00 #50206PixGuest
EXTRA TS do not require directly additional capacity in BSC or MFS. It is the amount of packet traffic that will require more GPU (in MFS)
EXTRA TS impacts only the ABIS usage.
But if by putting more EXTRA TS, it generates more GPRS traffic, then you’ll have to redesign GPU’s, Gb interfaces and Ater PS interfaces.
— how to proceed ?
As i said earlier, you need to perform a full study. I can’t explain it on a website !! It’s huge.10th January 2008 at 17:24 #50207TNSGuest
“… EXTRA TS do not require directly additional capacity in BSC…”
In fact it’s true if we use BSC Evolution.
If we use G2 BSC we need one TCUC per 2 EXTRA TS…
So it’s BSC resource consuming…
TNS10th January 2008 at 21:21 #50208PixGuest
Oh ? I wasn’t aware of that. I often read 1 TCUC = 4 FR TRX or 2 DR TRX, but never saw anything about ExtraTS. It’s very surprising.
I’m sorry I must ask, but are you sure about that ?11th January 2008 at 07:57 #50209HamdiGuest
it’s 100% sure as said TNS. So that’s the problem to determine the optimal “Extra TS” for a site using the sharing factor. i think that Alcatel recommends 4 “Extra TS” for a site of 3 sectors but i’m not sure about this. Anyone have more explanation about the calculation?11th January 2008 at 10:14 #50210PixGuest
**** The rule is 1 TCUC for 8 extra TS ****
2 ts only was a little low !!
i’m happy we talked about his, because i totally forgot about it.11th January 2008 at 10:22 #50211pixGuest
4 extra TS on a 4/4/4 BTS gives :
4 x 4 = 16 extra nibbles
3(1bc + 2sd) x 3 = 9 bonus nibbles
=> 25 “extra” nibbles available
1 MS in MCS9 needs 18 nibbles. That’s 4 basic nibbles + 14 “extra” nibbles.
So with 4 extra TS, you can have 1 MS in MCS9, or 2 MS with MCS7, etc…
If you cinlude free basic nibbles from other radio timeslots, then you might reach 2 MS with MCS9, etc…11th January 2008 at 17:14 #50212TNSGuest
“… **** The rule is 1 TCUC for 8 extra TS **** …”
It’s Right. My mistake was induced by the fact that me and my colleagues consider 1 TCU = 4 TCUC.
It’s NOT RIGHT. TCUC means a unit which is a part of the A-bis TSU.
I’ll try to summarize:
A9120 Evolium BSC ( G2 ) = up to 14 TSUs.
1 TSU = 8 TCUs ( TCUCs ). Each TCUC should be configured as FR TCUC or DR TCUC.
1 FR TCUC = 4 FR TRX or 8 Extra PS TS or mixture ( no DR TRX possibility )
1 DR TCUC = 2 DR TRX ( only ).
I think there is a limitation for the 1st TCUC of the 1st TSU of each BSC rack – it cannot be DR TCUC configured.
Hamdi, when we put a new BTS in the cities and towns, if we have a free A-bis and TSU resources we put 8 to 10 Extra TSs per BTS.
If it’s not possible we put as much as we can.
Then if we need resourses ( new TRXs or FR to DR reconfigurations ) we cut of what we need. Adding a 3rd A-bis is in too rare cases.
TNS11th January 2008 at 21:54 #50213pixGuest
3 abis per BTS is not something possible in alcatel BTS… so far 🙂14th January 2008 at 09:53 #50214HamdiGuest
Never heard about 3 abis links per BTS. MAX is 2 a primary and secondary Abis link in Alcatel.14th January 2008 at 19:18 #50215TNSGuest
Yes, it’s true.
I mean 3rd for the site…
For sites with 10 up to 24 TRXs we use 2 (MBI5/MBO2) or 3 (MBI3/MBO1) cabinets.
Usually they are connected via 2 A-bis links , in rare cases via 3 A-bis.
I’m sorry for the not very clear expression.