Reply To: Different questions



well naturally the pilots are sent to the eNodeB in a certain TTI, even if the signal processing (channel estimation, feedback parameter calculation) is performed infinitely fast, the feedback parameters are exploited at earliest in the next TTI, meaning due to the feedback and signalling from the UE to the eNodeB and back there is inherent delay of at least 1 TTI (one can also argue that this inherent delay is even 2 TTIs).

However, the signal processing at the eNodeB, mainly channel estimation, scheduling and link adaptation, takes some time and make the major part of the delay. For LTE-A 3GPP mentions a delay of 5 TTI for the feedback parameters. This is even a quite optimistic assumption in my opinion.