- This topic has 64 replies, 1 voice, and was last updated 8 years, 8 months ago by Saurabh.
19th January 2009 at 18:03 #40862PixGuest
I think you missed a step.. you can’t directly assume that 5000 calls = 5000 customers.
Normally, you work with erlangs, and then should use an Erlang B law translation:
5000 subscribers will perform 2 calls of 120seconds each during the busy hour.
This is equivalent to 5000 x 120 x 2 = 1 200 000 seconds = 20.000 erlangs.
Well, it becomes more complicated after that, that’s just a start.25th January 2009 at 08:37 #40863vipulGuest
can anyone answer me some of questions,
1) what is the difference between E1 and A-ter?
2) what is the capacity of ater?
3)suppose that BSC having 8 ater, then what does it mean?, how many calls be made using this 8 ater , is there any relationship between them?
vipul25th January 2009 at 14:11 #40864PixGuest
you should give a try to wikipedia, there are realy interesting stuff in there.
– E1 is way to use a physical link:
2Mb/s, 32 timeslots, ts0 reserved for framing/sync.
– Ater is the interface between BSC and Transcoder, based on E1. You can see the Ater as the name of a link, and E1 is the protocol to “use” this link.
Basically, 1 Ater = 1 E1.
1 Ater = 32ts, but ts0 is already used –> 1 Ater = 31 useful ts.
1 call on the radio interface will occupy 1/4 of an Ater timeslot.
But you have also at least 1 signalling timeslot every 4 Ater interfaces.
Roughly, you can safely assume that 1 Ater = 120 calls.
1 BSC with 8 Ater means the BSC is connected to the transcoder with 8 E1 links. 8 * 120 = 960 simultaneous calls max.
Regards,3rd February 2009 at 18:55 #40865nitinGuest
plz anyone tell diff b/w ater and A interface?4th February 2009 at 10:14 #40866NiceGuYGuest
Connection between the BSC and the TRAU is denoted
as Abis interface, while the connection between the
TRAU and the Core Network (MSC) is denoted as A interface…
B.R.4th February 2009 at 10:15 #40867NiceGuYGuest
SOrryyyy…. THe Connection between the BSC and the TRAU is denoted
as “ATER” interface, while the connection between the
TRAU and the Core Network (MSC) is denoted as “A” interface…
B.R.4th February 2009 at 15:00 #40868Jyoti VimalGuest
What is the capicity Of a BTS in terms of erlang. Plz explain.4th February 2009 at 16:36 #40869pixGuest
bts capacity depends on how many TRX you put in it. (a trx is a transceiver board).
1 TRX will (in average) carry up to 7 calls (8 timeslots in 1 TRX, 1 for signalling + 7 for calls). In case of half rate, 1 TRX = 14 calls.
You can place up to 24 TRX in one BTS.
24*7 = number of full rate calls
24*14= number of half rate calls5th February 2009 at 08:19 #40870JyotiGuest
How many erlang can a BTS deliver(Max.). Plz reply.5th February 2009 at 21:41 #40871PixGuest
I just gave you the number of channels, i let you do the erlang conversion… it’s not that difficult, you’ll see.6th February 2009 at 08:54 #40872vipulGuest
can anybody answer me the following some questions?
1) why the E1 is 2 mbps? why not it is greater or less then 2 mbps?
what is the reason of it?
2) how many TRX can be suppored by E1? can i put 14 TRX in single E1? if it is yes then how, or if it not then why?
3) what is the T1, where it is used, what is the capacity of T1?
4)why we use FXC E1/T1 in BTS?
Thanks6th February 2009 at 09:12 #40873Kamal kotechaGuest
1.E1 is of 2mbps,bco’z it is defined in its standard….having 32 time slots of 64k….while T1 is of 1.54mbps…having 24 time slots of 64k…mostly e1 is used…
2.in 1 e1 max 13 trx r possible,see the trafic manager for detail..where u define 14th one?
4.e1/t1 is used when we want to drop or bypass physical channel in bts,..like when fiu is used,e1/t1 card is required….6th February 2009 at 09:28 #40874TNSGuest
the answer of question 2 is vendor depending because of the way of RSL multiplexing…
T1 standard is used in South and North America
BR18th February 2009 at 16:36 #40875SourabhGuest
What is ater interface18th February 2009 at 17:45 #40876PixGuest
Ater CS is the interface between the BSC and the TC.
Ater PS is the interface between the BSC and the MFS.