A Seamless Dual-Link Handover Scheme with Optimized Threshold for C/U Plane Network in High-Speed Rail

Currently, 5G control/user (C/U) plane split heterogeneous network is a potential technology to provide high-speed rail (HSR) with higher capacity, better reliability and less co-channel interference communication. However, the Quality of Service (QoS) of the wireless HSR communication is greatly degraded due to frequent handover. In addition, a complete Inter-macrocell handover in C/U plane split network requires both the C-plane and U-plane service succeed during their individual handovers, which results in more handover problems. Some efforts have been made to design a handover scheme for C/U plane network. Motivated by this idea, we redesign a seamless dual-link handover scheme with optimized threshold for C/U plane split network. According to our proposed three principles, the optimized handover trigger algorithm depends not only on the hysteresis exceeding level, but also on the Received Signal Strength (RRS) of both antennas. Furthermore, the front antenna has more chances to execute handover while the rear antenna still keeps communicating with an Evolved Node B (eNB) in the new handover procedure. The simulation results demonstrate that the proposed scheme reduces the handover failure probability remarkably.