When UE will use Adaptive retransmission and non-adaptive retransmission in LTE MAC Layer?

Question

For non mobility UE i dont see any use case?

Answer 1

Hi,

It is not in UE side. It is upto ENB implementation. If ENB want adaptive then it can instruct to UE to use adaptive retx.

Comments

Hi,

In simple, Adaptive can be used in UL and Non-Adaptive can be used in DL.

The reason is, if enb uses non-adaptive in dl because it may busy in serving of multiple UEs and cant able to provide ack/nack or data on same subframe patterns ( like after 4ms). when it sending data or acknowledgment can be inform by DCI.

In case of uplink retransmissions and feedbacks or happening between UE and enodeb as agreement, hence no dci info needed.