Anchor-Based Active Set for User-Centric Multi-Connectivity: Mobility Enhancement and Performance Evaluation

Abstract

By organizing a dynamic transmission point group, user-centric networks (UCNs) are considered as a feasible solution to mine the potentials of dense networks where the densification gain is blocked by strong interference and frequent handovers. However, the state-of-art studies mostly focus on improving throughput performance. In this paper, user-centric multi-connectivity architecture is proposed, where multiple small cells serve the user as a user-specific active set to reduce the number of radio link failures (RLFs) and to increase the throughput gain, especially for cell-edge users. Especially, master eNodeB (MeNB) is chosen in the active set as a mobility anchor to control its neighboring small cells that are termed as slave eNodeBs (SeNBs), which reduces signaling overheads during handovers. To provide user-centric service, the active set follows the user's trajectory by adding new SeNB that provides strong signal strength and releasing serving SeNB that is far away from the user. Moreover, the design of key mobility management procedures for active set forming/reforming is taken into consideration. The results show that compared with single connectivity, the RLF in the proposed architecture shows a decrease of more than 50% when user speed is 3 km/h, and the average user throughput achieves an increase of around 74% gains when TP density is 2000 TPs/km2.