BAsic about TRX

[ar.babar]

Hi i am new in telecom...

i want to know that how many trx in one sector of bts ? is it present in RRU?

how many user can support one trx?

how many trx in one e1 and how many users or subcribers in one e1...


is no of trx matter from hardware vendor to vendor like zte, Hawaii , Nokia Siemens , and alcatel lucient???


if we know E1 and TRX can we calculate no of users support by BTS?

[Ghost78]

Hi;

I think it deponds on hardware vendor, and also BTS config.
In our network E/// hardware, we have up to 12 TRXs per Sector. 4TRXs per RRU, which means that one sector supprt 3 RRUs, in our case 1 900 and 2 1800.
and about users can be supported by one TRX, it deponds on how your TRX is configured, if it is BCCH TRX, you have to exclude 1 TS for BCCH, also how many SDCCH are there in each TRX, fixed or semi fixed PDCH "PS Time slot". Let me give one example, if one sector has 4 TRXs, 2 SDCCH are configured for it, and we have for Data 4 TS, so we will have 8*4-1-2-4=25 Time slot reserved for speech, which can support theorically in best conditions 50 users simultanously if with 100% Half Rate.
And to know how many TRXs can one E1 suppprt, you have first to know the configuration of the site, SDCCH Number, PS radio Time slots, and how many Time slots are defined as 64Ko for this E1, In general in our network one E1 can support 12 TRXs.

B.R

[Piojo]

Hi,

In 2G in nokia metrosite bts you can put 12 trx for each cabinet. You decide the combination of trx/sector that you need.

Here for first 2g sites, in downtown first bts was used using 4 trx for each sector, then 3 sectors used 12 trxs and using one cabinet all site was completed. Rural or low dense sites was on 2 trx for each sector. Total 6 trx for cabinet.

All this was on first sites for 2G network were i live.

On this model of bts, each trx has 8 time slots capability for handle calls. But first time slot is used for bcch broadcasting. Then, if you have 1 trx for sector, you have only 7 timeslots for calling, but if you have 2 trx for sector you have 7 + 8 time slots for suscribers (7 free from first trx, 8 free from second trx).


I hope you well,

best regards,

[Piojo]

Just another info,

I know only 3G RRU's, nokia flexi rru's and huawei rru's.

For nokia flexi, there is two models of rru, single rf module and dual rf module. Single has one trx, and dual has two. In both cases trx are not reconfigurable and are inside of monolithic rru.

I think the concept of trx not apply to rru modules, because you cant modify the transimssion or reception configuration using different modules. But, rru's necesarly need tx and rx modules, just are not modules. IMHO,

best regards,

[naveennadella]

Here is a samll calculation on number of TRX needed and number of subscibers it can serve

•Blocking Probability – 2%
•Site Configuration : 1+1+1
•No. of TRX per sector - 1 => 7 timeslots => 2.94 Erl capacity (from Erlang – B table)
•Capacity : 3 TRX 2.94erlangs = 8.82 Erl
•Erlang per subscriber requirement – 25mErl
•No. of simultaneous sub. Served = 8.82/.025 = 353

[jkhattak]

Thank you all for the nice information,

But how about we do it for the half rate, what about the Erlang calculation for 15 timeslots?

[rabkalamek]

in e*******, halfrate setting is divided into 2 category, 1st one is support amr and another doesn't support amr. if you using 100% of half rate setting, you get twice capacity of your time slot, so if you has configuration 4 sector which means 28 timeslots you get '56' timeslot if your halfrate setting 100%.

cmiiw