LTE: In which scenarios, an eNodeB initiates PDCCH order ?

Question

FlexRAN technology consists of RRH and BBU components. BBU can be deployed in data center while RRH can be deployed in remote location. As of now, I have two basic queries:
1. Is there any limitation on maximum distance between RRH and BBU connectivity ?
2. Is FlexRAN suitable for macro base station ?

Answer 1

when UE enter in unsynchronization state in RRC-CONNECTED, and network want to send data, network shall use PDCCH order to inform UE.
In short, When UE is in RRC connected state & Time Alignment timer expires in MAC layer and UE is considered uplink out-of-sync now.
If there is DL data in eNB buffer for UE but first UE has to be brought back to in-sync state and also it needs to reconfigured again with PUCCH/SRS resources.eNB sends PDCCH order to UE using DCI 1A format.

Comments

Thanks to answer this question. Well explained.