WHAT LATENCY IS EXPECTED IN LTE SYSTEM?

This is another interesting question. In order to answer this question. You need to understand the context. Meaning Latency or round trip time involves not only the radio but also the core network and the user equipment (UE).

User Plane

For user plane, the 3GPP target is to have latency less than 10 msec in a fully evolved LTE -SAE system.

User Plane is shown below.

Over Channel Setup

For overall channel setup time i.e., going from idle to active (connected mode) the latency is supposed to be less than 100 msec

Important Reminder

Now remember this 10 msec and 100 msec latencies are expected to be applicable in ideal conditions, You may not see these values always in the usually in the field practice.