After TA command from ENB How UE applies?

Question

receive TA command as 1 in RAR, does this means UE should send data one SF before? But i am not seeing this behavior in LTE logs, UE is sending data in same subframe.

Answer 1

The Timing Advance Command in RAR takes 11 bits and it can indicate an index value TA (0, 1, 2… 1282) which used to control the amount of timing adjustment that UE has to apply. The amount of the time alignment is given by NTA = TA × 16. The Timing Advance obtained via RAR is always positive

If TA = 1 ⇨ Timing Adjustment = NTA = 16 Ts = 16/30720000 sec = 0.5208 μs

So ue will start UL transmission is same subframe with .5208 μs before so that it should reach at enb in same subframe boundaries.