Dynamic Neighbor Cell List Management for Handover Optimization in LTE

Abstract

Self-optimization of the neighbor cell list (NCL) is expected to improve handover performance and reduce the need for site surveys. 3GPP Long Term Evolution (LTE) has introduced automatic neighbor relation (ANR), which enables a base station to manage neighbor cells on the basis of measurements made by mobiles. Because the radio coverage changes during network operations, it is essential to immediately update the NCL to improve handover performance, especially when the number of measured neighbor cells exceeds the upper limit of NCL size. In this paper, we propose a dynamic NCL management scheme to enhance NCL convergence and alleviate missing neighbor problems. The proposed scheme gives higher priority to newly detected neighbor cells over existing cells and ensures fast and accurate NCL updates after radio coverage changes. According to the LTE network simulations, the proposed scheme provides 70% faster recovery of the average radio link failure rate due to the missing neighbors compared with the non-prioritized scheme. It was also confirmed that the duration of missing neighbors is reduced by 39% on average.