- This topic has 9 replies, 1 voice, and was last updated 9 years, 10 months ago by Tanuj.
1st February 2011 at 13:02 #65669KaKaGuest
How to calclate Extra TS on BTS such as config all BTS = 12 TRX Extra TS =????2nd February 2011 at 13:43 #65670salahGuest
I want to know THE RELATION BETWEEN AN ERLAG AND SUBSCIBERS5th February 2011 at 14:17 #65671ankit limbasiyaGuest
How to calclate Extra TS on BTS such as config all BTS = 12 TRX Extra TS =????7th February 2011 at 10:29 #65672BobGuest
One TrX can provide 8 Channels over Air interface depending on your project some channels are used for signalling and the rest are allocated to TCH. (for signaling 16,32 and 64kbps rate are available)
12 TX as far as I know provide 12*2=24 TCH if 32kbps signaling used then + 1 omu =31 ch
so we have 24 Traffic channels so just put in ErlangB formula with GOS=.01 (For core GOS=.001)
the important matter is how many TCH you have —> use Erlang formula
Hope it comes in use!8th February 2011 at 10:46 #65673MRGGuest
Operators choose Erlangs/Subscriber depending upon clarity. Some choose 25mErl/Subs, some 40mErl/Subs and some go for half rate.
Just divide Erlang by above units.
eg: 1 Erlang/25m Erl=40 subs.8th February 2011 at 10:55 #65674MRGGuest
For 2TRUs:8X2=16 Time Slots
BCCH : 1 TS
SDCCH : 1 TS
TCH: 14 TS
Refer to Erlang B table for 14 TS with 0.2GoS=8.2Erlangs
Traffic 8.2 Erl at 2% GoS19th April 2011 at 14:52 #65675SebastianGuest
I got this problem at my Wireless Communications course:
“How many traffic channels may have a BTS with 4 frequencies?”
a. 29 TCH
b. 30 TCH
c. 31 TCH
d. 32 TCH
I would like to know the answer, and also the formula… Any help would be greatly appreciated.19th April 2011 at 19:01 #65676tudsGuest
4 frequency(ARFCN)x8 chls/ARFCN=32
cheers20th April 2011 at 21:05 #65677pixGuest
well, there are 32 timeslots,
but you need to carry some signalling channels.
So answers A, B, C are possible (those *may* be possible configurations).
Did you have any dimensioning guidelines in your course ?
For 4 TRX, the usual strategy is to put 1 BCCH ts + 2 SDCCH ts, that leaves 29 TCH. That is the best answer. But A, B, C *may* be possible…21st April 2011 at 02:28 #65678TanujGuest
yes there can be more SD channels depending on the subscribers density and there will also be PD channels