Research On Interference Alignment Technology Based On Antenna Selection

With the rapid development of mobile communication technologies,the number of mobile users has grown geometrically.The influx of a large number of users makes the spectrum resources become extremely tight,and the contradiction between limited spectrum resources and increasing user demands becomes more and more prominent.Therefore,it is imperative to increase the spectrum utilization rate of wireless communication systems.Antenna selection can reduce the RF link overhead and hardware cost brought by MIMO technology,improve system diversity gain and improve system reliability.Therefore,a joint optimization method combining antenna selection and interference alignment is of great significance for high-rate signal transmission.In this paper,the antenna selection algorithm and interference alignment are combined and researched in different scenarios.The specific research contents are as follows:1.For the K-user MIMO interference channel system,the traditional antenna selection algorithm fails to effectively improve the system capacity and spectrum utilization,and proposes an antenna selection algorithm that combines interference space projection.The algorithm performs singular value decomposition of the channel matrix,selects a set of the best feature sub-channels to transmit the signal,and then calculates the interference suppression matrix according to the MMSE principle.Finally,the optimal antenna subset is selected based on the spatial projection distance.The simulation results show that compared with the traditional antenna selection joint algorithm,the optimization algorithm significantly improves the system capacity.2.For the problem of serious interference between users and high complexity of antenna selection in MIMO systems,an interference alignment optimization algorithm based on cross-entropy antenna selection is proposed.The algorithm considers the mutual influence between the interference and the expected signal,and calculates the precoding and interference suppression matrix as a function of the power weighted sum of the two leaked into the corresponding subspace.Then,through the cross-entropy optimization algorithm,the signal-to-interference plus noise ratio(SINR)is optimized to construct the channel-related objective function,and the antenna selection problem is converted into a combinatorial optimization problem.Simulation results show that compared with the exhaustive antenna selection algorithm,the proposed algorithm achieves close to optimal algorithm performance while the search complexity is greatly reduced.