- This topic has 183 replies, 1 voice, and was last updated 13 years, 6 months ago by Sk.
15th March 2007 at 14:30 #37438TomarGuest
Hi Daniel, may be this basic definition could help you (from some documentation):
A TDMA frame consist of eight timeslots or physical channels. Each timeslot
has a length of 0.577 ms. The length of a TDMA frame is therefore 4.615 ms.
A 26-TDMA multi-frame is defined as a succession of 26 TDMA frames, and
corresponds to exactly 120 ms (26 x 4.615ms) cycle used for the TCH/F and
A 51-TDMA multi-frame is defined as a succession of 51 TDMA frames, and
corresponds to a 235 ms (51 x 4.615ms) cycle.
A Super-frame is a succession of 51 x 26 TDMA frames (6.12 sec). This is
the smallest cycle for which the organization of all channels is repeated,
because of these smallest common denominators.
A Hyper-frame is a succession of 2048 x 51 x 26 TDMA frames (3 h, 28 min,
53 sec & 760 ms). It is a numbering period and determines all the cycles in the
transmission of the radio path. The frame number in the hyper-frame (absolute
TDMA frame number) is e.g. the smallest cycle used for frequency hopping
We have seen that a physical channel is defined by a frequency and a timeslot
number. We have also seen that a physical channel can be used to carry various
logical channels. At any point in time, the MS must know on which logical channel to
send to the BTS and which logical channel is being sent from the BTS. For example
the timeslot allocated to a user is usually used for traffic (TCH) but sometimes is used
for signalling (either FACCH or SACCH). The MS and BTS must know when to
send/receive each of these logical channels.
In order to achieve this, sequences of logical channels are defined. They are called
‘multi-frames’. There are two types of multi-frames. The traffic channel multi-frame is
26-TDMA frames long, and the BTS signalling multi-frame is 51 TDMA frames long.
Each multi-frame can have different combinations of logical channels depending on
the configuration of the BTS.16th March 2007 at 05:04 #37439PromodGuest
Is their anybody ready to explain about LMRG,QMRG,NX,PX and PBGT? I would like to know the appications of these parameters in simple explaination..pls help me out.
What is the NECI value? I hope this will help out when you have AMR HR in the network which will support the all classes of the mobile.
pls suggest me…20th March 2007 at 09:35 #37440gabaryGuest
if we want to make a dual band RBS 2206 with one sector 900 had 8 TRU and the another sector 1800 had 4 TRU in the same direction .. the question is we can assign one BCCH for these two sector ?? , because of it is no possible for two sector to be in the same direction with 2 BCCH .20th March 2007 at 11:55 #37441PromodGuest
When u have the TCH availability is low in the perticular cell, will it going to affect the DCR and HSR in the network? If it affect can anybody give me the reason for the same.
In some cells we have very good DCR and in some cells the DCR is worst can anybody give the reason?
Ex:TCH availabilyt is 27% and DCR is 1.3 and HSR is 97.23, The worst is cell DCR id 7.6 and HSR is 78.34
for the same TCH availability.21st March 2007 at 05:21 #37442PROMODGuest
Nobody is ready to anwser my question? pls somebody have help me out? From past 3 days i am asking queries nobody is reply>
Pls help me out..21st March 2007 at 06:38 #37443ParthaGuest
TCH Availability will not affect DCR(if u mean Drop Call rate).
But it may affect HSR(Handover Success rate) depending on how many neighbours are trying to handover to this cell(assuming this is the better cell for the incoming handover).21st March 2007 at 12:52 #37444PROMODGuest
1.can i know the reason why it is getting reduced? Is it due to hardware issue or due to some other reason?
2.Why it will affect the HSR due to low TCH availability even though there is no congestion and no hardware alarm?27th March 2007 at 12:15 #37445BoreauGuest
I actually got a tems investigation 7.0 and I would like to change rxqual parameters.
i tried with info element sbut it’s not working
thx27th March 2007 at 15:35 #37446pixGuest
i’m not familiar with TEMS 7.0 (only 6.1), but it should be fairly identical to the 6.1… so what you’re doing is correct.
why not send an email to TEMS directly ? you must be entitled to some support after having purchased it ?28th March 2007 at 01:32 #37447Gito PrastomoGuest
Try to export to Map Info then modify with thematic, if you experience problem with info element..
Gito21st July 2007 at 09:05 #37448TanvirGuest
Would you please explain me in details about cell planning and the steps of frequency planning. What r the trade offs. And the most important is Optimization.
I am really in need of these features.
waiting for reply.
Tanvir23rd July 2007 at 06:35 #37449krGuest
why do we use AMR ?
(Is it a funda to increase the call carrying capacity or to increase the signal strength as it gives an improvement of around S/N = 4-6 dB.)
Is it implemented specifically with Tch half rate ?
what is the difference if implemented with Tch HR of FR?23rd July 2007 at 07:40 #37450PixGuest
AMR is not a feature itself, it is more like the availability to use different codecs, rather than just EFR, FR or HR.
You have two features associated :
codec adaptation : within a same channel rate (FR or HR), it is possible to change the codec, in order to increase or decrease the protection of the speech. When changing from one codec to another, the call remains in the same timeslot. It is not a Handover.
channel adaptation : depending on the C/I and the cell load, the BSC can order to make a HO from FR to HR (good quality, loaded cell) or from HR to FR (bad quality and cell with less load).
FR to HR : the call performs a HO from a FR timeslot to a HR timeslot, in order to gain space. Since the C/I is good, the speech quality is not affected by this HO.
HR to FR : other way around 🙂
The codec adaptation… maybe i should explain more in details :
you have a subset of codecs for HR timeslots and another subset of codecs for FR timeslots. So you can apply codec adaptation for HR calls only, FR calls only or BOTH.
At the same time, the codec on the UL path and the codec at the DL path can be different. Each path is handled separately.
Ok… enough :))
Regards,23rd July 2007 at 08:16 #37451kantGuest
hi pix , tomar n vanderlay
could u pls look into my qestion
How many TRX can be connected in one E1?
each TRX needs 2 E1 time slots ( 64*2= 128 kbps )
each TRX needs needs 16 kbps for signalling , so 4 TRX can fit in 1 E1 time slot
so for 4/4/4 configuration 24 E1 time slots for actual voice traffic and 3 E1 time slots for signalling.
0 time slot for synchronization and 16th time slot for O&M link .
So, 24+3+2 = 29 time slots are occupied . We are left with only 3 E1 time slots . I can put one more TRX , again occupying 2 E1 time slots and the last one for signalling out of which 48 kbps is still free.
So , all in all we can connect 13 TRX at max with 1:4 multiplexing .
But , I have connected 14 TRX in one E1 in Nortel System .
And at the most we can connect 15 TRX in one E1 with LAPD concentrated mode 2 .
But I could not justify more than 13 TRX in one E1 logically.
1. What is 1:4 mulitplexing ?
2. What is 1:1 multiplexing in which we can at max 10 TRX at max( correct me if wrong )
3. What is LAPD concentrated mode 2?
4. Is it important that only 16th E1 time slot should be given for O& M link ?23rd July 2007 at 08:42 #37452krGuest
thanks for the ansr
m sorry if i irritated u ….. the expression i got from ur last words Ok…. Enough !
AMR is an audio data compression scheme. We have 14 modes of codec….. 8 for FR channel and 6 for HR channel …..i got it
but my question is why do we implement it ?
To increase the weak signal ( robustness of the n/w as it provides improvement upto S/N = 4-6 dB )
To increase the call carrying capacity as it increases or decreases the data rate using appropriate codecs depending upon the RF conditions …. as u told link adaptation …..