- This topic has 10 replies, 1 voice, and was last updated 11 years, 6 months ago by David.
5th October 2009 at 14:15 #59035ColinGuest
i need to know 1 cell with 27Tch how match erlang and subscribers can afford, with many regards.5th October 2009 at 16:55 #59036pixGuest
click on the online calculators, on the left of this page.
choose 27 channels and 2% blocking, it will output amount of erlangs.
divide result (in erlang) by 0.025, that’s your number of subscribers (25mErl/subs is a good average value).6th October 2009 at 10:25 #59037ColinGuest
thx for the quick answer i used the online calculator and the result was 19.250 and i think that means the maximum traffic this cell can afford, but when you check this very cell from the OMC statistics it giving me 42.95 (Traffic Volume on TCH)
so what do u think please6th October 2009 at 17:52 #59038PixGuest
The value 42 erlangs, is it only during one hour, or over the whole day ?
Then, are you using Half Rate, or Full Rate ?
If HR, you must multiply the number of channels by 2 : 27 * 2 = 54.
Then, check the congestion rate at the measured hour, and enter this value in the blocking rate, instead of the the value 2%.6th October 2009 at 17:52 #59039PixGuest
No… sorry, keep the 2% 🙂7th October 2009 at 06:11 #59040ColinGuest
no this is only during the busy hour and it’s not HR it is full rate, but the TCH congestion Rate (Overflow) at busy hour for that cell is 11.87%
so u still think i should keep the 2%
cheers7th October 2009 at 06:39 #59041PixGuest
What is the formula used for traffic volume ? Is it in Erlangs ? Do you see the same kind of values in other cells ? Or are those more realistic (= falling within the limits given by erlang B) ?
In this traffic volume : is it also taking into account packet data ?
And finally, the numbers are just too much of a coincidence… (double of what they should be).
Are you certain there is no HR in the cell ? Could you double check (in statistics for example : traffic in HR vs. traffic in FR). Sorry to be so stubborn, as I said : the coincidence is too good to miss.7th October 2009 at 12:28 #59042BijoyGuest
One matter should also be taken care that if your system gos increases your carried erlang also increases;like carried traffic with 2% GOS is less than that with 3% GOS,i think he has got the correct figure,only he has to do is too seek for carrier addition7th October 2009 at 13:24 #59043ColinGuest
you were right to be stubborn because the cell was using HR sorry for the inconvenience but still i have another one with 29 Channels and 27.9 Erlang it doesn’t include packet data am using Huawei BSC6000 and their M2000 for the performance, but still i feel like my blocking rate is more than 2 so what do u think7th October 2009 at 21:30 #59044PixGuest
The hardest thing to do is ask the right question. I notice that most of the time, when facing an issue, I want to send an email to our tech support. And while writing the question with all details, I can already find the answer myself :))
27 erlangs on 29 TCH is possible, but your congestion rate must be very high ? How high is it ?
>>> Bijoy, the erlang B gives the “offered” traffic, not “carried” traffic, it is very confusing to apply the erl B formula on the actual measurement of the traffic. The measurement gives the “carried” traffic.
I stop here because I can feel the headache already…
Cheers,14th October 2009 at 10:10 #59045DavidGuest
The 27 Erlang u speak is the peak traffic or BHT? N could you tell me out of how many TRX have you arrived to 29 Channels? Lemme do a wild guess.