Research On Interference Suppression Algorithms In Mmwave Multi-cell

As one of the key components of 5G communication networks,millimeter wave can rich the spectrum bandwidth and provide massive available resources.Considering the serious path-loss of millimeter wave and the traditional beamforming methods would cause the interference among multiple links in the dense scenario,which restricts the application of millimeter wave,a reasonable interference suppression algorithm is essential for the millimeter wave.Therefore,this thesis focuses on the interference suppression issue of millimeter wave to reduce the complexity and power consumption under multi-cell environment,concrete research contents are as follows:1.The increasing users of the beam switching for interference suppression lead to higher computational complexity in the multi-cell millimeter wave communications.Aiming at this problem,a beam overlapping interference model in the multi user multi-cell millimeter wave network is introduced and a lower complexity beam interference suppression algorithm based on user grouping is researched.The studied algorithm operates beam switching and multi-cell cooperative transmission for part of the users when there exists beam interference due to high user density.In particular,considering the distinct interference suffered by each user,the researched dual-threshold user grouping method can effectively solve the frequent switching problem in the base station caused by multi-cell cooperative transmission in the multi-cell environment.Simulation results show that the studied algorithm can reduce the computational complexity of beam switching and approach ideal system capacity compared with conventional interference suppression algorithms without grouping users.2.Aiming at the aggravated interference caused by the increasing number of users and cells,a transmit power minimization algorithm,which combines the user association and beamwidth selection,is researched.In the premise of guaranteeing the authenticity of millimeter wave application scenario,a millimeter wave system model is introduced by integrating the roll off nature of Gaussian directional antenna model and the reflectivity of two-ray channel model.Particularly,combined with the user association according to distributed framework,the particle swarm optimization algorithm is employed to choose the optimal transmit as well as receive beamwidth,so as to adapt the non-convexity of transmit power minimization problem in millimeter wave cell.Simulation results validate the superior performance of the researched algorithm in terms of the transmit power of base stations and the interference suppression,compared with the existing interference suppression algorithms which ignores the transmit power of base stations.