Enhanced uplink handover scheme for improvement of energy efficiency and QoS in LTE-A/5G HetNet with ultra-dense small cells

To construct a femtocell based ultra-dense network (UDN) is the important way to satisfy the ever-growing data traffic demands in the next generation mobile networks. However, it causes frequent handovers (HOs), thus leading to negative consequences such as increased power consumption and poor quality of service (QoS). This paper represents a research on the uplink handover (UL-HO) being watched recently and proposes a new method to further improve the energy efficient and QoS. First, we confirm the UL-HO mechanism, formulate the power consumption caused by UL-HO and compare downlink handover (DL-HO) with UL-HO in terms of the performance parameters including the power consumption, handover rate (HOR), handover failure rate (HOFR), ping-pong rate (PPR), delay, packet loss rate (PLR) and throughput during handover (HO). Then, it is proved through simulation that the reliable target cell determination scheme considering uplink reference signal received power (UL-RSRP), available bandwidth, direction of user equipment (UE), and admission control is lower in HOR, HOFR, PPR, power consumption, delay and PLR. In particular, we propose a new algorithm to determine the reasonable target cell considering UL-RSRP, available bandwidth and moving direction of UE, thus reducing HOR and PPR. The improved UL-HO scheme can be implemented easily by adding some functions besides the upper-layer protocol, while it can provide a lot of benefits such as reduced power consumption, delay, frequent HOs resulting in reducing HOR and PPR. Accordingly, this can be introduced into 5G as a HO scheme.