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# TRX calculation

Viewing 7 posts - 1 through 7 (of 7 total)
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• #56303
sam
Guest

Hi pix,
In one cell (3TRX) I have over 60% tch congestion. I want to increase the trx. Is there having any formula for excel to calculate required trx to overcome from this congestion please?

BR//
Sam

#56304
pix
Guest

hi sam,

you could look at the erlang table to find out how much capacity you should have.

3 TRX = 21 channels capa
erlangB(21 channels, 60% cong) = 51 erlangs of incoming ‘offered’ traffic

you should have enough capacity to welcome 51 erlangs @ 2%
Erlang B (51 erl, 2% cong) = 62 channels

now, you have to take into account call repetition.. if each user tries to connect 3 times for one call, the actual cong% is only 20%.
–> 22.8 erlangs offered
–> you need 4.5 TRX.

Basically, you need 4 TRX with HR activated, or at least 5 TRX in FR.

#56305
sam
Guest

Thanks pix. Thank you very much.

#56306
Pix
Guest

Just to be clear, i assume a call repetition = 3, but that’s not a parameter. It’s a subscriber behaviour.

It might be more or less important, i don’t know 🙂

#56307
Gerald
Guest

SDCCH accessibility =

Number of SDCCH Success/ (Total Number of SDCCH Attempt – Not defined)

#56308
MOJI
Guest

Dear Pix.
would u please share your formula to calculate erlangB(170 channels, 50% cong) =???
thanx

#56309
AKS
Guest

Pl told me – how TRX capacity calculated????

Viewing 7 posts - 1 through 7 (of 7 total)
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