Handover Optimization for 4G Wireless Networks

The authors present a velocity-based bicasting handover scheme to optimize link layer handover performance for 4G wireless networks. Before presenting their scheme, as related works, they firstly describe general handover protocols which have been proposed in the previous research, in terms of the layers of network protocol stack. Then, they introduce state-of-the-art trends for handover protocols in three representative standardization groups of IEEE 802.16, 3GPP LTE, and 3GPP2. Finally, they present the proposed bicasting handover scheme. Original bicasting handover scheme enables all potential target base stations for a mobile station (MS) which prepares for handover to keep bicasted data, in advance before the MS actually performs handover. This scheme minimizes the packet transmission delay caused by handover, which achieves the seamless connectivity. However, it leads to an aggressive consumption of backhaul network resources. Moreover, if this scheme gets widely adopted for high data rate services and the demand for these services grows, it is expected that the amount of backhaul network resources consumed by the scheme will significantly increase. Therefore, the authors propose a novel bicasting handover scheme which not only minimizes link layer handover delay but also reduces the consumption of backhaul network resources in 4G wireless networks. For the proposed scheme, they exploit the velocity parameter of MS and a novel concept of bicasting threshold is specified for the proposed mobile speed groups. Simulations prove the efficiency of the proposed scheme over the original one in reducing the amount of consumed backhaul network resources without inducing any service quality degradation.