Performance Evaluation for Uplink Measurement Based Small Cell Selection in User-Centric Networks

Abstract

Ultra-Dense Network (UDN) is a clear trend for future 5G. However, using exciting small cell selection (SCS) schemes, which are totally based on downlink measurement, dense deployment of small cells would bring about frequent measurement, intolerable ping-pong (PP) rate and handover failure (HOF) rate. In this paper, an uplink measurement based SCS scheme is proposed for a user-centric networks based on the analysis of mobility management challenges of UDN, and the handover performance of the proposed SCS scheme is evaluated. In the proposed SCS scheme, the small cells measure uplink reference signals of users and then user-centric new radio (NR) cells would be established, which reduces the measurement process that the user feedbacks measurement reports to small cells that have transmitted downlink reference signals to the user. The relationship between key handover parameters and mobility performance in user-centric network is illustrated to look for the optimal configuration of Time-to-Trigger (TTT) and A3 Offset and achieve low PP rate and HOF rate. Besides, the impact of NR cell size on handover performance is evaluated to provide basis for the forming/reforming of user-centric NR cell. Simulation results show that compared with traditional downlink measurement based SCS scheme, the proposed SCS scheme can reduce the PP rate and HOF rate by up to 21% and 56%, respectively.