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

Yuan He,Wanqing Huang,Hongtao Zhang

doi:10.1109/access.2019.2932574

Yuan He, Wanqing Huang + Show 1 more

Open Access

https://doi.org/10.1109/access.2019.2932574

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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/km 2 .

Highlights

The dramatic growth in the amount of wireless data traffic demands pushes the investigation of ultra-dense networks (UDNs) for the fifth generation (5G) and beyond [1], which increases network spectrum efficiency by shrinking average link length [2]
An anchor-based active set is formed for the user-centric multi-connectivity architecture in this paper to enhance mobility performance in user-centric networks (UCNs)
The anchor TP is selected from the active set, acting as the master eNodeB (MeNB), while the other TPs in active set act as the slave eNodeBs (SeNBs) which only provide user service in the coverage of active sets

Summary

INTRODUCTION

The dramatic growth in the amount of wireless data traffic demands pushes the investigation of ultra-dense networks (UDNs) for the fifth generation (5G) and beyond [1], which increases network spectrum efficiency by shrinking average link length [2]. In order to reduce the service interruptions and to improve the network throughput, multi-connectivity is applied to maintain multiple connections for mobile UEs. In this paper, an anchor-based active set for user-centric multi-connectivity is proposed in UCN. Different from handover procedure in the current LTE system, there are four kinds of mobility management of the anchor-based active set, including SeNB addition, SeNB release, SeNB modification and MeNB handover. The SeNB release event is triggered at time trel when the RSRP from the serving SeNB TP y becomes lower than the RSRP from the best serving TP in the active set by an offset ηrel, expressed as the following condition, and the condition is fulfilled for a certain time TTT, which is given by RSRPy < max(RSRPs)+ηrel, for trel −TTT < t < trel (3). Where SINRni,u is the SINR value of UE u connected with TP i at sub-channel n, and W is the bandwidth of sub-channel n

MODEL FOR RLF

PERFORMANCE EVALUATION

Findings

CONCLUSION