Frame Structure and Multiframe questions

R M rm.engineer84 at
Sat Apr 26 06:44:28 UTC 2014


I am trying to understand the Multiframe structure in GSM. Here is my

Lets say that in a particular cell, only two GSM frequencies are available
to cater to all the traffic.

FB is the frequency of the beacon channel and FT is the frequency of the
traffic channel.

FBT0 is having the following configuration FCCH + SCH + BCCH + CCCH.

Now a phone which is in this cell, gets paged for an incoming SMS.

The phone responds to the paging request and gets an immediate assignment.
The immediate assignment assigns it a channel

with the following configuration:

FTT2 and channel multiplexing is SDCCH/8 + SACCH/8.

Now how does the phone know the multiframe structure of FTT2 ?

In other words how does the phone know how long it has to wait, so that it
can transmit in the right time-slot ?

The same question applies to the BTS if we are talking about down-link ?

Is there a relation between the multiframe structure of FBT0 and FTT2 ?

Thanks and Regards,
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