Research On The Multi-service Oriented Vertical Handoff Technology In Ubiquitous Networks

With the development of wireless network communication technology, in order to meet the users' personalized, multi-service needs, future network environment will be a variety of heterogeneous wireless networks coexisting. Current trends and requirements of network communication is to provide users with a seamless multi-service needs across heterogeneous networks on the basis of ensuring quality of service(Quality of Service, Qo S). Vertical handoff technology is the foundation of a variety of heterogeneous networks coexisting, also is the key and core technologies on the realization of mobile users to seamlessly roam.In this paper, Research focus on the Multi-service Oriented Vertical Handoff Technology in Ubiquitous Networks, mainly include:1. Combining with the current development situation of heterogeneous wireless networks, this paper analyses a variety of handoff types and control modes, focusing on the vertical handoff process and performance indicators, in-depth study of some typical vertical handover algorithms in heterogeneous network environment. Considering some shortcomings of the current algorithms existing, this paper exploratorily proposed a multi-attribute judgment vertical handoff strategy for multi-service in ubiquitous network environment. This strategy uses the threshold of SINR as handoff trigger condition, to avoid the "ping-pong effect" on the basis of reflecting the quality of the network. Then by taking advantage of the network terminal moving speed to filter and score the candidate networks, considering the impact of mobility on network quality of service, and reducing unnecessary calculations of decision algorithm. In the judgment of the designed algorithm this paper considers multi-attribute decision factors, weights designed considers the network environment and Qo S requirements. Also in the application of multi-service by assigning weights corresponding service value, this paper uses double cost function fully considered the service priorities and reducing implementation complexity.2. This paper uses 3G-WLAN loosely integration model to design and achieve a 3G-WLAN integration platform system. Handoff strategy papers presented were realized and verified by the system. This paper describes the overall architecture and function modules of the system, focus on the detail design and implementation of the handoff module and built environment through the system related tests. The test results indicate that the design of the system enables the user to access the corresponding adaptive network by handoff.3. This paper verified proposed strategy by simulation. By setting the simulation scenarios and network parameters, comparing with the typical RSS-based decision algorithm, this paper analyses the performance of vertical handoff strategy proposed. Simulation results show that the proposed handoff strategy can effectively reduce the handoff numbers, and the verdict can better reflect the Qo S requirements and network environment, improving scientific rationality of the handoff decision.This article is for vertical handover scenarios in the same time the presence of a number of active service. Research has important significance for realizing the users' multi-service network needs and roam seamlessly handoff in the future ubiquitous heterogeneous.