GSM basics

ayat,

yes, to me, this is correct.

Be sure to use the TCH erlang, and not the SDCCH + TCH.

and then, you must know that during the TCH phase, there are few seconds during which the call is being connected and during which there is ringing. This delay is included in the TCH erlang, but is not being paid by the subscriber.

Therefore, I would remove 5% of the total erlang value. (9.05 – 5%)
(average call duration = 60 seconds, average waiting duration = 3 seconds)

I hope i’m being clear and logic 🙂

regards

Dear, Pix
thanks
i understand your answer , i think it is logic , but do you think the traffic of ringing and call setup is high to effected on calculation ?????/
thanks so much

hello,

well, you have to consider the average duration of one call, not the erlang traffic on the whole cell !

To find the value, it is easy : erlang divided by number of TCH assignments (for normal assignments + for incoming handovers), and multiply the result by 3600.

But usually you can consider that the average is about 60 seconds… it is a value that you find frequently worldwide.

And usually, you wait an average of 3 seconds before your call is being answered (or before you answer the incoming call).

That is where the 5% come from. You can decide or not to take it into account, but if you want a realistic simulation, you’d better throw it in..

If the cumulated duration of the calls in a cell = 60 minutes (for example), the cumulated duration of the “waiting”/”ringing” phase is about 3 minutes. But that duration is split over the whole amount of calls that were processed in the cell.

Regards,
Pix

actually, it is recommended to be equal, but not mandatory… a cell can work fine with a TSC different than the BCC.

don’t ask me why, cuz i’ve no idea what the TSC is actually doing… (used during the HO ACCESS ?)

Dear sir,

Why we use DC voltage in telecom sector?

In case of DC, why we use 48 V, not any other voltage?

Could u plz. answer me ?

Dear, all
hello
Plz i repeat my question plz could you help me to do my job ?
my job is how to calculate BSC traffic revenue for certain company ?
i tried with help from Mr. pix
but i found the result (revenue so huge and i am sure the revenue for this company it is not as the result
my claculation way is
generated traffic in BH (Busy hour *60 * cost of one minute

fpr example
one cell has 2 TRX , 12 TCH
and it generated 10 ERL in BH
i converted TCH traffic to minute by multiply *60
Plz help me

Dear sir,

Could u pls. tell me from which the control channel BCCH and SDCCH are generated, whether from BTS or from BSC?