[kapil]

GPRS logical channels mirroring GSM logical channels. This statement is true with some exception. One such exception is GSM logical channel SDCCH. GPRS does not have such logical channel.

Question: Explain why GPRS does not need equivalent to the GSM SDCCH control channel

[pix]

i would appreciate a “hello”, a “please” and a “thank you”..

The SDCCH channel is a bit useless in GSM, when it comes to setting up a call. It is actually usefull to handle other tasks such as location update, SMS, etc… it allows to multiplex 8 channels on one timeslot, for simple operations, so there is a gain of capacity to put all small tasks on the same timeslots.

In GPRS, the only type of operation needed is the allocation of a TBF. And a GPRS timeslot (PDCH) can already be multiplexed among different TBF, if needed.

[Karthik]

Can anyone please tell me what sort of signaling is used between BSC and TCU? Is it SS7 or LAPD?

[Pavel]

Karthik,

If CSU is transcoder unit – then answer is different for different equipment vendors.

TC, never have signalling point, so it never have SS7 connection to BSC.

In Nokia DX200 BSS – transcoder is connected to BSC via LAP-D only for O&M linkage.

In Ericsson AXE 810 there is no separate transcoder, usually it is combiled node BSC/TRX, so it have internal connection via DL bus.

[kapil]

thank you very much for the replies

[Author]

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