Why the UL and DL frame structure of SDCCH shows SDCCH and SACCH at different TS.
Where as in TCH it is point to point mapping.
I mean when BTS is on TCH(in DL) the MS is also on TCH(in UL).
when the BTS is on SACCH in DL the MS is on SACCH in UL.
But when the MS is on SDCCH in UL the BTS is on SACCH and vice versa. Why ???