GSM network dimensioning

[dacoder]

If we have mErl per subscriber and total number of subscribers how do we calculate no. of trx required, no. of BTS required and max. site configuration? Is the data enough for calculation?
Lets suppose 25mErl per subscriber and total of 5 million subscribers as an arbitrary data for calculation.

Thanks

[Shakeel_15]

Hi,

To design and dimension a network it has several phases.

Like 25 m erlang is estimate traffic and 5 million subscriber expected

25m*500000= 125000 traffic

Now after calculating the estimated traffic use Erlangb or c formula with 2% GOS and calculate the resources. Excel addins available for this

After calculating the channels divide this value from 8 and get the number of trxs for TCH TRAFFIC. For SDCCH Traffic it is approximately 28% of TCH TRAFFIC.

After getting the TRXs you have to calculate E1s.

Usually 1 E1 Support 14 TRX with GPRS and when you go for EDGE the capacity reduced.

Anyways this is some quick intro there are tutorials available for GSM Dimensioning so if you need it let me know i will share it.

BR

If we have mErl per subscriber and total number of subscribers how do we calculate no. of trx required, no. of BTS required and max. site configuration? Is the data enough for calculation?
Lets suppose 25mErl per subscriber and total of 5 million subscribers as an arbitrary data for calculation.

Thanks

[dacoder]

Hi,

To design and dimension a network it has several phases.

Like 25 m erlang is estimate traffic and 5 million subscriber expected

25m*500000= 125000 traffic

Now after calculating the estimated traffic use Erlangb or c formula with 2% GOS and calculate the resources. Excel addins available for this

After calculating the channels divide this value from 8 and get the number of trxs for TCH TRAFFIC. For SDCCH Traffic it is approximately 28% of TCH TRAFFIC.

After getting the TRXs you have to calculate E1s.

Usually 1 E1 Support 14 TRX with GPRS and when you go for EDGE the capacity reduced.

Anyways this is some quick intro there are tutorials available for GSM Dimensioning so if you need it let me know i will share it.

BR

Thanks... one question though: how do we find required resources for 125000 erl traffic from erlang B table? For 2% gos maxm. traffic is 136.8 erl as per table.
btw please share the GSM dimensioning docs that you have.

[Ghost78]

hi;

for your first question, how to get ressources for 125000 Erl, i suggest to download from this link one library for excel and use it directly using fonctions imported by this library, http://abstractmicro.com/erlang/index.htm

for the GSM dimensionning docs : http://www.finetopix.com/showthread....neering-in-GSM

[Philippe]

First, derive the number of sites for coverage (based on link budget and depending on the area and clutter morphology to be covered). Then divide your traffic by this number of sites. Apply ErlangB law to derive how many TRX per site you need and check the TRX configuration is consistent with the spectrum bandwitdh you have been allocated.

[jkhattak]

Thank you all for the good information,
I have recently registered on this site and were keenly looking for these information, i will be thankful if someone can please guide me with the Erlang B table calculation..
OR if i someone can please take a time out and help me with findind TRX number for a giving subscribers lets suppose 86000 using 15mErlangs not 25mErlangs

Waiting for guidance
Thanking in advance

[jkhattak]

Dear dacoder,

hope you do good, i know this thread is old but i am looking for the same informaiton, please guide if you know the answer to your post
Thanks