- This topic has 13 replies, 1 voice, and was last updated 12 years, 3 months ago by pix.
17th December 2008 at 10:02 #55064AMRGuest
Can any body tell me how AMR increase traffic on cell with out increasing Congestion let say before AMR the traffic is 20 ERL but when AMR activated traffic increased without increase in Congestion.17th December 2008 at 17:51 #55065pixGuest
because you activated AMR Half Rate, I suppose ?
The benefit you see is mostly linked to the “half rate” part of the AMR HR 🙂18th December 2008 at 07:27 #55066AMRGuest
as for normal speech mode also there is halfrate but the thing that pay my attention is that let say cell A with both FR and HR took 32 ERl and whe i activate the AMR the traffic increased to 40 ERL with out increase in Congestion on TCH.
regards18th December 2008 at 11:19 #55067TZHGuest
Check your dimensioning of traffic for the cell/site, existing cell/site using static TCHs or dynamic TCHs settings?
AMR uses smooth transition between different bit rates and TCH HR-FR modes by determining the C/I condition, and also determining the congestion. The feature is also an anti-inteference tech, so you’d be allow to use more HR under bad air interface conditions. So it actually “increases” your capacity. (Only from Huawei equipment point of view, not sure other vendors using these paramters in AMR feature)18th December 2008 at 14:07 #55068AMRGuest
also my operator is huawei18th December 2008 at 16:56 #55069PixGuest
yes, it’s the same AMR, whichever vendor.
In other words, TMZ, instead of a call drop, the call is kept with AMR under poor radio conditions, so there is more erlang in the cell. That makes perfect sense.
The smooth transition you’re talking about is the fact that an AMR phone can start a call in FR and change to HR if asked by the network. Whereas a “dual rate” phone must keep the same codec from start to end of call (within the same cell).21st December 2008 at 12:04 #55070MCIGuest
I wanna know about activation of AMR in SIEMENS systems.
Could anyone please send me this information in my email: firstname.lastname@example.org December 2008 at 19:50 #55071EvgenGuest
TZH, you fully right – it depend from thresholod parameters for reselection from AMRFR to AMRHR (C/I, HOC,POC). But in our network main reason for increasing traffic after AMRHR activation – it MS which not support HR, but support AMRHR (such as Nokia 6630 and Nokia smartphones OS Symbian 9 with old SW version).24th December 2008 at 19:01 #55072MCIGuest
thank you for your attention but could you please tell me for steps of activation AMR in seimens systems or tell me the address of these procedure in Siemns documents?8th January 2009 at 16:24 #55073AMRGuest
I would like to know if We activated AMR so there will be different traffic for each sppeech mode let say
EFR is 40 erl
HR is 30 erl
AMRFR is 10 erl
AMRHR is 20
how to calculate the real traffic is the sum of all traffic or there is onter summation could you please help me8th January 2009 at 19:53 #55074PixGuest
You can divide the HR and AMR HR traffic by 2, sum up everything and compare it to the Erlang B capacity of the cell
40+15+10+10 = 75 erl / xxx capacity
1 HR erlang = 0.5 FR erlang 🙂9th January 2009 at 08:50 #55075AMRGuest
Thank you for your support but iam little bit confused if a cell takes 75 erlang with 6 TRXs after AMR active Congestion is not increase in the same time traffic increased as from erlang B 6 TRX with all TCH full rate and GOS 2% it will be around 33 Erl and If 50% HR active it be around 54 Erl . so what iwas supposing the Congestion must be increased.11th January 2009 at 07:48 #55076AMRGuest
is it possible to use in Cell let say four TRX two TRX support AMR and other Two TRX support EFFR/HR and how they make handover.12th January 2009 at 09:28 #55077pixGuest
6 TRX = 42 timeslots FR or 84 timeslots HR
42 channels –> 32.8 erlangs capacity @ 2% congestion
84 channels –> 72.5 erlangs capacity @ 2% congestion
If you’re seeing 75 erlangs, it means that most of your traffic is probably in half rate (AMR or not), and that your congestion rate is around 2%.
The erlang B is not exact in GSM, because of the TCH queue…