Research On Multi-Radio Access Selection In Heterogeneous Network

In the future development of wireless communication networks, heterogeneous network is considered to be the most promising network architecture.It implements the integration of a variety of wireless access technologies.Existing and future wireless access systems will be integrated into a seamless organic whole which will meet the requirements of different type services of future users.Multi-radio access selection (MRAS) algorithm is a key technology in radio resource management of heterogeneous network. The result of choice will not only affect the user's service quality, but also has a great impact on the entire network resource utilization and load balance.Existing MRAS algorithms are introduced and the problems of present algorithms are discussed in this paper,The most significant problem is that the existing MRAS ignores asymmetry of the servers which will have large impact on network selection.Call admission control (CAC) allows permission of service when both link of system satisfy the access requirements.Asymmetry of the servers will cause unbalance between the uplink load and downlink load. When there are a large differences between uplink load and downlink load, one of the links will refuse the access requirement because of the lack of resources, while the other link, there are remaining resources.The asymmetry of services will increase the blocking probability of the heterogeneous network. It is a waste of system resources and reduces the network throughput. This paper proposes a new MRAS based on DL/UL load balance which realizes the load balance between uplink and downlink by selecting an appropriate network as the targeted network for a new service.It can reduce the blocking rate, improve the system resource utilization and enlarge throughput of the heterogeneous network.In the last part, a system-level simulation platform based on the heterogeneous wireless network is designed by matlab.It evaluated the performance of the proposed algorithm.The simulation results show that the new algorithm has a large improvement in the blocking rate, DL and UL throughput compared with traditional MRAS based on load balance in heterogeneous network.