Research On D2D-Assisted Network Offloading Scheme

Ultra-dense networks can effectively improve system coverage,enhancing spectrum efficiency,alleviating the user demand in the hot spot area and improving quality of service.However,the ultra-dense network faces the problem of load balancing.In particular,it is likely that some cells are seriously congested while the load of adjacent cells is low.In order to balance the load between adjacent small base stations,making the network to accommodate more users,many schemes have been proposed.This paper focuses on the network offloading problem based on D2D(Device-to-Device)communication.Firstly,in order to improve the number of accessible users and improve the throughput of the network,this paper proposes a relay selection and resource allocation scheme aiming at the maximum link achievable rate,using D2 D receiving users as relays,multiplexing cellular uplinks.The interference caused by D2 D is controlled within the allowable range by power control to maximize the network throughput,and the newly initiated communication request user in the fully loaded base station is offloaded to the adjacent light load base station by means of two-hop relay.The maximum achievable rate offloading scheme proposed in this paper is verified by simulation.The simulation results show that the scheme increases the number of network accessible users under the premise of ensuring network throughput.Secondly,this paper proposes a two-step relay selection and resource allocation scheme,which reduces the computational complexity of the algorithm through the Hungarian algorithm in resource allocation.Secondly,this paper proposes a two-step relay selection and resource allocation scheme,which reduces the computational complexity of the algorithm through the Hungarian algorithm,and studies the relay selection scheme.Considering the residual power of relay users and the queuing delay of relay link,the optimal relay selection scheme of user residual power and transmission delay is proposed.The network performance under different relay options is compared by simulation.The simulation results show that the three D2 D cooperative network offload schemes proposed in this paper increase the number of accessible users under the premise of ensuring network throughput.The optimal scheme of electricity quantity has achieved good results in throughput,and the optimal scheme of delay and the maximum achievable rate scheme have achieved good results in the number of accessible users.