Research And Simulated Implementation Of QoS Handoff Mechanisms Based On PSO With ABC Supported

With rapid development of Internet technology, network applications are no longer limited with traditional applications such as document transmission, email etc.. Several new mobile business appear continuously. Therefore, NGI (Next Generation Internet) should be a heterogeneous network which contains both wired and wireless access technologies. Nowadays, to satisfy people's increasing communication requirements, NGI must provide QoS (Quality of Service) guarantee and support ABC (Always Best Connected). In order that people can choose the "best" way and device to communicate anywhere and at any time, handoff management becomes a hot topic in the area of communication.In this paper, the QoS handoff mechanism which supported ABC in NGI environment is discussed. In order to support ABC, fuzziness of network information, user QoS requirements, user preference, charges that the user is willing to pay and benefits of network provider are considered. The network model and mathematic model are designed to solve the problem of the inaccuracy of network parameters based on fuzzy theory. In order to guarantee that different QoS parameters'weights which are set by users are reasonable, AHP (Analytic Hierarchy Process) is introduced to do coherence test. So as to calculate the similarity between network service policies and users'QoS requirements, multi-objective decision method is used to do coherence measurement. A simple service management strategy and a dynamic pricing strategy are proposed to ensure the fairness between users and network providers. In order to truly achieve all-win, game theory of micro-economics is introduced to compute the user utility and network provider utility, and Nash equilibrium is used to take into account the benefits of both sides. In addition, since the problem discussed is a NP-complete problem, two PSO(Particle Swarm Optimization) algorithms which use iterative method to find the optimal solution are adopted to choose the most reasonable distribution scheme of access networks.In order to verify the feasibility and effectivity of the handoff mechanism and to evaluate the performance of the algorithm, simulation is done with corresponding models set up in NS2 (Network Simulator 2) environment. The simulation results show that the mechanism is feasible and effective. Users'basic QoS requirements and preference of networks and providers are considered comprehensively, while the interests of users and network providers are taken into account to ensure the fairness of handoff decision. Therefore, the mechanism can solve the QoS handoff decision problem with ABC supported in NGI effectively.