A measurement-based study of handover improvement through range expansion and interference coordination

Although the range expansion and inter-cell interference coordination (ICIC) have been shown to successfully enhance the capacity and load balancing in the heterogeneous network (HetNet), their impacts on the handover performance are not fully understood in existing studies. In this paper, a novel measurement-based approach is adopted to investigate these issues, where the real measured data of the reference signal received power (RSRP) in a macro-pico co-channel deployment are collected. Then the mobility performance in terms of the handover failure rate and ping-pong rate is simulated with various ICIC schemes in the same reality environment. This has been made possible by modeling the possible handover failure events based on evaluating the downlink received signal-to-interference-plus-noise ratio (SINR) from RSRP. The simulation results indicate that range expansion together with ICIC can have positive or negative influences on macroto-pico, pico-to-macro, pico-to-pico and macro-to-macro handovers in a HetNet. The existing static ICIC or mobilitybased ICIC cannot handle the intra-layer (pico-to-pico and macro-to-macro) interference, thus limiting their abilities to improve the mobility performance. Motivated by this, a dynamic-ICIC-aided handover procedure is proposed. The proposed handover enhancement method is more flexible and effective in mitigating both the inter-layer and intra-layer interference, outperforming the existing methods significantly. Copyright c ⃝ 2013 John Wiley & Sons, Ltd.