[SKY]

Thank you very much, Pix.

BRs,

[raj]

hi,
Is it possible to send an sms using dynamic sdcch.?
thanks in advance

[pix]

hello,

dynamic sdcch is just a normal sdcch, which is allocated on demand by the BSC. The usage of this sdcch can be anything, including SMS.

So to answer your question : YES 🙂

regards,
pix

[R]

hi pix

with reference to your ans that Routing Area doesn’t happen on SDCCH , could u pls elaborate it further …..

does that mean that the Routing Area update is happening on TCH/SACCH (PDCH/PACCH) ?

one more question i have :

while accesing GPRS/EDGE one time slot can be shared by 8 users in UL. Now the BSC has to send the power control notifications to MS and the MS will be sending the ACK/NACK.

My question is that both the above processes are done on SACCH ?
And if it happens on SACCH …. will the SACCH will be shared by 8 users if I percieve that 8 users are sitting on one time slot ?/

[pix]

routing area occurs on the PDCH (= pdtch + pacch)

there is no SACCH in GPRS. a MS that sends data in uplink will be allocated “n” PDCH in UL (= pdtch + pacch) and 1 PACCH in DL, most of the time.

There is no closed loop power control in GPRS. The MFS doesn’t recommend any power control to the MS, because it is the MS that decides which TX POWER it should use, without any confirmation from MSC, BSC or BTS.

The GPRS UL PC is VERY specific, and is controlled by ALPHA and GAMMA radio parameters. It is not impacted at all by the GSM power control parameters.

When a TS is shared among 6 users (isn’t the max nb of UL users = 6 on one TS ??) then they will each send, in turn, a burst of data or signalling.

[R]

hi pix

i do not have dedicated separate channels ( PBCCH and PACCH ) for GPRS in my network.

the same control channels ( voice control channels) are being used for GPRS signalling.

could u pls brief me what do u put under GPRS signalling and which control channel is used for that signalling if I don’t have separate dedicated channels for GPRS .

And according to me it should be a max of 8 users per time slot .
Reason being that in the segmentatioin of data in the MAC layer the MAC header contains the USF which contains 3 bits and accordingly we can have 8 users or 7 if one is used for PRACH.

[Raul]

Hi all,
I have one ques: In MOC when is exactly a TCH assigned.. before the ringing or after and, if after then ringing alert is carried on which channel? is it SDCCH?

[pix]

ok, yeah, 8 USF available, but only 6 for users : one for PRACH (even if not used) and one to say “nobody should transmit during next block”

there is always dedicated gprs channels. PRACH, PBCCH and PAGCH are NOT dedicated channels, but rather “common” channels.
Nobody uses those GPRS common channels, so your situation is very standard.

When a MS has a PDCH in UL, it means that it can send data during this TS when it hears its own USF on the concurrent DL timeslot. But if the BSS asks this MS to send signalling instead of data (for instance, a packet acknowledgment), then the PDCH carries signalling. It’s not like in GSM where there is statically one SACCH every 26 bursts.

If you activte NC2 though, the MS will send packet measurement report at regular interval.

Those signalling is carried physically on the PDCH, but logically it’s not a PDTCH anymore, it’s a PACCH.

[R]

pix, u mean to say that the same PDCH is used to send signalling as well, the only thing to understand is that while sending signalling it becomes PACCH ( packet associated control channel ).

is it correct , if i say it is much like a TCH being used as a FACCH ( a 20ms block is stolen ) during a handover in voice ?

one more question Pix:
if i study the multiframe of GPRS , out of 52 TDMA frames 2 are PTCCH ( for sending TA information to MS using GPRS ) and 2 frames are idle frames……what for these idle frames are used ??

rgrds

[R]

Raul

the ringing tone goes on TCH only .

[pix]

Quote “pix, u mean to say that the same PDCH is used to send signalling as well, the only thing to understand is that while sending signalling it becomes PACCH ( packet associated control channel ).

is it correct , if i say it is much like a TCH being used as a FACCH ( a 20ms block is stolen ) during a handover in voice ?”

Yes, that’s correct. With the difference that the TCH bursts that are stolent are “lost” forever. While the data that shuld have been sent is not lost : it will be sent in future block.

Quote: “if i study the multiframe of GPRS , out of 52 TDMA frames 2 are PTCCH ( for sending TA information to MS using GPRS ) and 2 frames are idle frames……what for these idle frames are used ??”

Idle frames are used for the MS to measure the noise on the current frequency. Without these idle TS, there is no opportunity to hear the noise (or “interferer”) : the MS will always hear the main carrier signal.

So the MS can compute a C/I, that is used to choose the best Coding Scheme (in GPRS). In Edge, the C/I is not used as far as i know. Maybe it’s vendor’s dependent.

Regards,
Pix

[Raul]

Hi R thnx, That means if i give a call to a frnd and he doesnot respond then throughout the rining duration a TCH will be occupied.
In that case miss calls shud also be charged by operators….

[Pix]

Raul,

But they aren’t 🙂 The billing is started as soon as the other party answers the phone.

Don’t worry, the operators are making enough money as it is, don’t feel bad about them wasting resources during the ringing phase 🙂

[Raul]

Hey Pix thnx,
Anyone body having any idea about the MB(message bus) in Nokia BSC. about its exact role and has anyone faced any MB failures?? if yes how to troubleshoot such a problem.??

[leon]

what is the difference between SDCCH and BCCH and what it does?

[Author]

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