Required Count of TRXs

[justdream]

Dears,

Sorry I'm confusing
Could you advice me
how to do study to calculate rerquired Number of TRX per cell
taking in account
TCH Traffic
SD Traffic
GPRS+Edge Data [this is most confusing part for me]

[justdream]

Hi Dears,

Any idea how to calculate required TRX count taking GPRS/ Edge data in consideration

[dannthemann]

Hi,

I think you first should to estimate the traffic inyour cell for the 3 types of traffic: SD traffic, TCH (voice) traffic and data traffic (PDCH).

Once you have those figures, you should use the erlang formula to calculate the channels needed to deal with each type of traffic (bear in mind the block rate you can accept for each type of traffic): the number of SD channels needed, the number of TCH (full or half rate) channels needed and the number of PDCH channels number. Of course, don't forget to take into account the dynamic allocation features that will allow you to dynamically allocate different type of channels depending on the needs in each moment.

For signalling purposes take into account that a single time slot can handle up to 8 SD channels if you are using SDCCH8 channels.
Voice traffic channels can dynamically change between full and half rate depending on the thresholds configured.
And the data channels (PDCH) can also be converted from TCHs dynamically.

In case of any doubt follow the standard configuration

delete.jpg

And only one PDCH per TRX.

And of course, don't forget to activate the dynamic conversion feature.

BRs

[justdream]

Hi,

I think you first should to estimate the traffic inyour cell for the 3 types of traffic: SD traffic, TCH (voice) traffic and data traffic (PDCH).

Once you have those figures, you should use the erlang formula to calculate the channels needed to deal with each type of traffic (bear in mind the block rate you can accept for each type of traffic): the number of SD channels needed, the number of TCH (full or half rate) channels needed and the number of PDCH channels number. Of course, don't forget to take into account the dynamic allocation features that will allow you to dynamically allocate different type of channels depending on the needs in each moment.

For signalling purposes take into account that a single time slot can handle up to 8 SD channels if you are using SDCCH8 channels.
Voice traffic channels can dynamically change between full and half rate depending on the thresholds configured.
And the data channels (PDCH) can also be converted from TCHs dynamically.

In case of any doubt follow the standard configuration

delete.jpg

And only one PDCH per TRX.

And of course, don't forget to activate the dynamic conversion feature.

BRs

TCH & SD Traffic are in Erlang so simply I could use Erlang-B table for them without any problem
but PDCH Traffic Data in Bits, how Erlang-B table can be used for Data case

[dannthemann]

Hi, you are right. It is not possible to use the erlang-B table with data.

But, in my experience, we calculate the voice and SD traffics and then we define the number of TRXs adding some extra capacity.

And then we use the time slot #5 to allocate a PDCH. And to make possible to handle the extra needs for data traffic we use the dynamic conversion feature, so when needed, TCH channels are converted into PDCH channels.

BRs