Timing Advance (TA) in LTE.

Question

What is timing Advance and what is the significance of it and more importantly why this concept was not there in UMTS.

Answer 1

Timing advance is used by eNB to get informed UE to make uplink transmissions align with subframe timing so that eNB can decode successfully. For example. if enodebb expect data from UE at time t and it sends data either at (t-delta )or (t + delta) time , eNodeb would not able to decode the data. Similarly another more important concept is power control.