Research On Seamless Handoff Technology For Heterogeneous Open Wireless Network

With the rapid development of mobile telecommunication technology, wireless access networks with different standards, formats and specifications are emerging, they constitute a complex heterogeneous wireless network environment. These heterogeneous wireless networks can’t achieve unified network management and can’t coordinate to provide users timely services together. Experts designed a solution which is called heterogeneous wireless networks convergence to solve these challenges. Seamless handoff technology is the primary technology to achieve heterogeneous wireless networks convergence.To achieve seamless handoff in heterogeneous wireless network, we firstly need to select the best target network. Therefore we design a new network convergence architecture which is called heterogeneous open wireless network. Heterogeneous open wireless network applies the concept that control layer departs with the data layer in wireless network which derived from software defined network. The new architecture is constituted with programmable data layer, centralized control layer, south bound protocol and north bound protocol. In the paper, software radio technology is used to realize soft base stations to construct programmable data layer. Centralized control layer uses a unified controller to achieve the nodes’ state information, so that better handoff decision algorithms can be designed and deployed in the controller, therefore the controller can select the best target handoff network for the terminals, also we can undertake research on mobility management, wireless resource management and so on in the controller.Further, to ensure session continuity for seamless handoff, the paper studies the heterogeneous open wireless network which consists of LTE and WLAN. Assuming that the target handoff network is decided, the paper designs two new seamless handoff mechanisms:IP address encapsulation and source routing encapsulation. These two new handoff mechanisms can not only achieve session continuity, but also have less delay and high throughput.