Study of Paging Enhancements for UE Energy Saving in 5G New Radio

The paging functionality in New Radio release 15 can be energy consuming, especially if a UE is rarely paged or its Paging Occasion (PO) suffers from a high false paging alarm rate. Therefore, paging enhancements for UE power saving are being developed in New Radio release 17. In this work, the concept of Early Paging Indication (EPI), where a UE is notified in advance of its PO whether the UE has to monitor the PO, is examined. As a result, the UE can skip the time-frequency synchronization phase prior to a PO, if the UE need not monitor the PO. The EPI can be signaled via a Downlink Control Information (DCI) message carried in the Physical Downlink Control Channel or via a Reference Signal, e.g. the Secondary Synchronization Signal. Furthermore, the EPI may carry sub-grouping information to divide the UEs, sharing the same PO, into sub-groups, resulting in lower group paging rate and fewer false paging alarms. Simulation results show the EPI can lead to 17 %-34% energy savings as compared to the release 15 basic paging procedure, depending on the UE SINR radio conditions. If the EPI is complemented with sub-group information an additional 10% energy can be saved, while also mitigating the impact of high group paging rates. The DCI-based EPI can flexibly contain the sub-group indication, and potentially also Short Message and other information, and is therefore the preferred option.