Research On Vertical Handoff For Multi-business Environment In Heterogeneous Wireless Networks

As wireless communication network technology has been developed unceasingly, the situation that a single-type network ruled the market has gone for ever. The heterogeneous network integrated with multiple technical background and operators has become the mainstream in the future market. The next generation wireless communication network will be several-type wireless network to jointly provide wireless communication environment with complementary and cooperation, so as to supply various business services for increasingly powerful mobile terminal devices. Wireless communication network are designed to provide mobile terminal users with communication with others in any business types anytime and anywhere, however, there are numerous difference existed in the integrated network due to network performance, covering scope and access technology. Furthermore, the mobile terminal development can launch more business than before when developing up to now. Network shift are increasingly complicated under such circumstances. Therefore, switch technology becomes a research focus in communication field under condition of heterogeneous wireless network. An effective and seamless switch decision strategy which can ensure mobile terminal to conduct all business communication without restriction, is of great theoretical significance and practical value.This thesis summarized and analyzed research status of switch technology under heterogeneous wireless network environment, studied switch mechanism of heterogeneous wireless networks and different switch decision algorithm. Moreover, it put forward two improved vertical switching algorithm based on mobility in combination with mobile terminals in reality and present situation of network business service. To be specific, this thesis mainly completed the following:Firstly, a vertical switch algorithm is put forward based on mobility under multiple business circumstances for multiple business service of wireless heterogeneous network and mobility of mobile terminals. The algorithm fully considers discrepancy and various influence properties of multiple business of terminals, analyzed influences on switch network process by terminal mobile, so that the switch algorithm can better meet real application scene. The simulation results showed that the vertical switch algorithm based on mobility has made certain improvement in decreasing ping-pong effect and reducing switch blocking rate under multiple business circumstances.Secondly, as the mobile terminal device has been improving its performance and the system has become more intelligent, some predictive vertical switch strategies are appearing gradually. A QoS predictive vertical switch algorithm is proposed based on business QoS in combination with QoS of multiple terminal business. The algorithm conducted detailed analysis on features and shortcomings of an existed decision strategy to switch door limit through terminal speed prediction, introduced diversity of candidate network and terminal business without consideration, and improved the algorithm into a vertical switch decision strategy better suitable for network integration and business diversity. Through analysis on stimulation results, it verified that predictive switch algorithm based on business QoS reduced switch time delay to certain degree, and optimized loading of heterogeneous wireless network.The research results showed that useful theoretical reference can be provided for further improvement of wireless network service quality if vertical switch algorithm between heterogeneous networks are researched on network business services of wireless heterogeneous network and mobility of mobile terminal.