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.