A Handover Scheme for Subnet Mobility in Heterogeneous Networks

an increase number of wireless applications consist of a network of mobile nodes moving together in high velocity, existing protocols focused on roaming of single node, and there are no mature solutions to keeping uninterrupted high-speed mobile communications for roaming the entire subnet with a moving velocity as high as a vehicle. In this paper, firstly we propose the idea of the new handover scheme based on mobile IP, and then introduce the principle and key issues for subnet mobility in networks. The station (STA), a wireless communications equipments in mobile wireless subnet, taking the access point (AP) as the gateway, implements the multiple-hop subnet mobile IP by cooperation of the home agent, the foreign agent, interior network routing agent and reused tunneling, thus to overcome the limitation of one hop between the movement node (MN) to the exit of the tunnel. A dynamic next AP scanning and finding model and a handover trigger model named Well-time is designed to provide low latency. We implement the scheme on re-designed STA and AP, the experiment shows that the new scheme enables a mobile subnet to handover seamlessly across heterogeneous wireless networks and maintains all ongoing high-speed communications with the nodes in fixed networks, when moving at a high velocity up to 50km/h.