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# BTS Capacity

• This topic has 22 replies, 1 voice, and was last updated 6 years ago by Chanmyae.
Viewing 15 posts - 1 through 15 (of 23 total)
• Author
Posts
• #51869
scor
Guest

How many subscribers can successful call establishments in one TRX

Thks

#51870
Pix
Guest

Call establishments :
8 call setup procedures per timeslot SDCCH
1 active call per timeslot TCH in full rate
2 active calls per timeslot TCH in half rate

in one TRX, you have 8 timeslots, so it just depends on your configuration.

however, the number of calls is not an information we use, we rather use erlang values (based on erlang B law)

#51871
scor
Guest

Thks PIX.

For 2+2+2 config

16*3=48 Active calls(Full Rate Erlang). Am I Right

What about the signalling part timeslots?

Thks

#51872
pix
Guest

2+2+2

1 sector 2 TRX = 2*8 timeslots = 1 BCCH + 1 SDCCH + 14 TCH
–> 14 simultaneous calls + 8 simultaneous call setups

2+2+2 –> 42 simultaneous calls + 24 simulatenous call setups.

“1 call setup” is a procedure to seize a TCH, it lasts about 4 seconds.

#51873
Manoj Gupta
Guest

How many calls can do from one BTS of Conf. 4 4 4 in full rate capacity

#51874
Prabeen
Guest

Hi Manoj,

A maximum of 2160 FR calls shall be made. That is 2160/3 = 720 calls per cell. But remember this is just theorotical calculation giving an average of 25merl to a subscriber.

#51875
kalim
Guest

max no of callers, if
4+4+4(using 8 users)=96 users at H.R
4+4+4(using 7 users)=84 users at H.R

4+4+4(using 8 users)=192users at F.R

4+4+4(using 7 users)=168 users at F.R

#51876
Rafi
Guest

Dear Kalim,
It looks you have interchanged FR and HR. FR is always less than HR. HR is less than or equal to 50% of FR.

#51877
machzar
Guest

hi Prabeen, Pix and all, would you explain to me more why you can get theoritical 2160FR

because from my calculation for 4/4/4 in FR,
I just have only 90 simulatenuos call and only 24 call setup.

it comes from :
1 sector 4 Trx = 4*8 TS = 32 TS
= BCCH + SDCCH + 30TCH
4/4/4 –> 96 call + 24 call setup.

thx before.

#51878
pix
Guest

Hi,

the call setup is done on SDCCH and then released.
One call setup lasts only 3 seconds. So the 24 channels are used repeatedly until the 90 TCH are used.

In a restaurant, there are only 2 waiters for 30 tables. The 2 waiters are serving every table once in a while.
The SDCCH is doing the same : it is serving every TCH once in a while (to locate a MS on it).

I hope the analogy works..
(no, no need to tip the SDCCH at the call release)
Cheers
pix

#51879
Sineesh C
Guest

Hi Prabeen,

Please Explain the Amazing Technology of supporting 2160(FR)simultaneous User in one BTS.

What is the meaning value 25merl that you given user ?.

#51880
Prabeen
Guest

Hi Sineesh,

Its not simultaneous calls. Its capacity of a 4+4+4 cell taking 25merl per sub.

25merl: This is the average erlang that shall be utilized by a subscriber. This value is used for all theorotical calculation for capacity issues.

Calculation: 4TRX supports a maximum of 18.4erl. 18.4/.025 = 736 subscribers. The same for all the 3 sectors gives you around 2200 subscribers. BUT NOT SIMULTANEOUS.

#51881
Amex
Guest

Dear Friends
Could you plz help me!!!
Can i put 2RBS per sector (Ericsson 2206, band 900)? Is it posible to synchronize them?
Present logical configuration is 3,3,3 (XRANGE and TCC activated) phisical is 12,12,12 i want to increse it to 4,4,4 means Phizical 24,24,24
Thx
Amex

#51882
Prabeen
Guest

Hi,
It depends on number of arfcn u have. How many arfcn do u have?

#51883
Amex
Guest

Hi Prabeen. thx for you answer.
we are using hoping and 18 arfcn on them. what can i do? this site serving huge coverage

Viewing 15 posts - 1 through 15 (of 23 total)
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