Home » Topics » Telecom Design » why 2 steal bits are used in TCH burst ?
giri Guest
in TCH burst packet:
3 tail Bits
57 data bits
1 steal bit
26 training squence bits
1 steal bit
57 data bits
3 tail Bits
8.25 gaurd band
wht do we need 2 steal bits here, we ca do it with one steal bit only to identify a data or a control signal(FACCH)
NarChai Guest
2 stealing bits in TCH use for FACCH (Fast Associated Control Channel)is used when a handover is requied
good lock
giri Guest
than u can use only one bit for FACCH and TCH identifying
why u need two bits
giri Guest
u can identify TCH or FACCH from 1 bit only
why 2 bits are used??
pix Guest
naveen Guest
Probably the second stealing bit might be used for future use! 🙂
giri Guest
for Pix
in spec 05.03 it is mention that two stealing bits r for two halfs of the message part
in the spec it is mentioned that voice data and FACCH goes at the same burst.
pix Guest
so maybe it has something to do with half rate ? 1 FACCH bit per channel…
that was my first assumption, but since HR are sent once every 2 TS (and not each time on half of the timeslot), it didn’t seem very logical… but i don’t know, really.
giri Guest
pix–
it nothing to do with half rate
FACCH is used when mobile is trying for handover
so u may not know when it can try for handover
one possiblity is send FACCH in the whole burst and TCH in the next burst
but in the spec it is not the case(reason i dont know)
Bhanu Guest
2 steal bits r used to indiacte if the upper or lower segment have been stolen.
giri Guest
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