Research On Topology Management And Resource Allocation In Multi-User Wireless Networks

Interference alignment(IA)is a promising technique for interference management in wireless networks.However,most of the existing IA works are based on symmetric multi-user networks.To meet the requirements of practical applications,we consider asymmetric interference networks where the location of each user is randomly distributed.Then,topology management and resource allocation issues are considered in asymmetric interference networks in this paper.Through proposed topology management scheme and resource allocation strategy,the spectrum efficiency of the networks can be effectively improved.The work of this paper can be mainly divided into two parts:(1)When the path-loss is large,interference will become sufficiently weak,and can be treated as noise.Hence,aligning the interference via IA becomes unnecessary.In this paper,a spectrum-efficient topology management(TM)scheme is proposed for asymmetric interference networks.In this scheme,for a pair far away from others,solely adopting spatial multiplexing(SM)as a SM subnetwork is more spectrum-efficient.On the other hand,for the users close to each other,jointly comprising an IA subnetwork can be the better choice.First,the decision criterion is presented to perform network partition according to the distance between pairs.Then,the asymmetric interference network can be interpreted as an undirected graph.Hence,the network partition problem transformed into the graph partition problem.In addition,we present the designs of the precoding and decoding matrices for the IA and SM subnetworks.(2)Antenna selection(AS)and power allocation(PA)techniques are exploited to further improve the performance of TM in asymmetric interference networks.First,the AS technique is applied to IA subnetworks.Through fully utilizing the redundant antennas,more optional antenna combinations can be provided to achieve the diversity gain.Then,based on the geometric programming(GP)framework,the transmitted power is allocated among transmitters of both the IA and SM subnetworks,to optimize the spectrum efficiency of the network.Based on these two techniques for TM scheme,the joint optimization of AS and PA is developed through a stepped resource allocation optimization strategy to further improve the performance with low computational complexity.Simulation results show that the effectiveness of proposed TM schemes and resource allocation strategy.