The Research On Load Balancing And Fairness In Relay Based Cellular Networks

The OFDMA cellular networks based on OFDM modulation technology can get higher anti-interference ability and spectrum utilization than the traditional cellular networks.The user diversity gain is obtained by dividing the sub channel to the cell user,which provides higher data transmission rate for the user in the cell.However,due to the severe inter cell interference(ICI)and the imbalance distribution of system load,the resources utilization cell system is unbalanced and the fairness of the system and the QoS of users,especially the cell edge users,are difficult to be effectively guaranteed.Therefore,the load balancing of OFDMA cellular communication has become a hot issue.With the help of relay technology,the traditional cellular system not only can realize the expansion of coverage based on the existing network architecture to improve the cell capacity but also can effectively overcome the impact of shadow fading at high frequency to improve quality of signal and reduce the cost of network construction.However,the introduction of the relay makes the topological structure and transmission time slot of the cellular network change,and the relay node may be a new source of interference.In the downlink OFDMA cellular network based on inter cell relay load balancing analysis,we propose a resource allocation scheme based on frequency spectrum and time slot division,and analyzes the interference on this communication model.Considering the downlink,we analyze the subcarrier residual of BS and RS area respectively and compute the change of system throughput after average redistribution.Finally,the simulation results show that the proposed scheme can effectively alleviate the shortage of resources in overloaded cell and the low utilization rate of the resources in the adjacent area.It also improve the throughput of the system.Based on the analysis of the inter cell relay load balancing in downlink OFDMA cellular networks,the fairness of the system is analyzed.In the existing model,first,we propose a distance based fairness scheduling algorithm,which is used for the redistribution of the remaining sub-carriers in the BS and RS region.Secondly,we consider the optimization of the relay radius when the fairness of the system is as higher as possible.Finally,the simulation results verify the correctness of our theory,and the fairness of the system is improved.