Research On Access Selection Algorithm For Heterogeneous Wireless Networks Under Low-load Conditions

In recent years,with the continuous expansion of wireless networks,the energy consumption of wireless networks has aroused wide attention.Due to the uneven distribution of wireless network traffic in time domain and spatial domain,a large number of densely deployed base stations in heterogeneous wireless networks cause serious waste of resources under low-load conditions.Under this background,the access selection algorithms in heterogeneous wireless networks under low-load conditions are introduced.The algorithms dynamically adjust resources occupied by users by effective collaboration among heterogeneous wireless networks and finally sleep some BSs to achieve energy saving.In TD-LTE/WiMAX heterogeneous converged network environment,an access selection algorithm based on load gathering for heterogeneous wireless networks under low-load conditions is proposed.The proposed algorithm considers increasing the difference of load rates of access networks moderately under the constraint on the blocking rate of service requirement,concentrates the traffic load to the active base stations and makes more low-load base stations go to sleep sooner.Firstly the number of services that base stations to be dormant need to transfer is calculated.Then the access control model is constructed and network resources are reasonably allocated to transferred services and new calls according to access control strategy obtained by chaos immune algorithm.Simulation demonstrates that the proposed algorithm compared to the reference algorithm makes more low-load base stations go to sleep sooner,improves the system energy efficiency and satisfies the blocking rate constraint of service requirement.Considering the problem that the single attribute decision making cannot measure the rationality of network selection,this paper proposes an access selection algorithm based on multiple attribute decision making for heterogeneous wireless networks under low-load conditions.To reasonably allocate resources to transferred services and new calls,the algorithm not only considers available channels,blocking probability and time delay of each network to assess its performance,but also considers the influence of selecting different access networks on the overall performance.Simulation results show that the algorithm can further improve the system performance on the premise of achieving the same energy-saving effect.