Research On Precoding Based On Low Resolution MU-MIMO

With the continuous increase of users in the cell,the application of MU-MIMO technology has become more extensive.Compared with a single antenna system,its advantage lies in its higher spectrum utilization and channel capacity,which effectively reduces the complexity of the receiving end and promotes the fair distribution of power among users.Because of the increase in the number of users,channel interference and user interference greatly reduce the performance of the system and increase the overhead cost of the system.In response to the above problems,this article has conducted the following research:(1)Starting from the single-user MIMO system,explain the transmission model of the system,the diversity technology and multiplexing technology used by the system,and focus on the precoding technology and its algorithm in the MIMO system for the accuracy of the acquisition of channel state information.Improve channel capacity and spectrum utilization.(2)One-bit precoding supports the use of 1-bit DACs in base stations,which can significantly save hardware costs and power consumption for large-scale MUMIMO systems.Aiming at the problem of enhanced reception processing for singleantenna and multi-antenna mobile stations,using the embedded structure in the simulation non-convex optimization problem,based on alternate minimization and mathematical programming with equalization constraints,approximate maximum likelihood detection,minimum mean square error and other methods,Proposed MMSEERP precoding based on one-bit resolution DACs.The simulation results show that the MMSE-ERP precoding can significantly improve the receiving and processing capabilities of the receiving end compared with the control one-bit precoding.(3)In a large-scale antenna array system,if the signal has a constant envelope characteristic,that is,a constant amplitude value,its amplitude value has nothing to do with the channel implementation and the information symbols sent.In a large-scale antenna array system,hardware complexity and power consumption are the limiting factors,and each antenna element requires dedicated hardware components.These components include DACs,whose complexity increases exponentially with increasing resolution.Based on the MU-MIMO system equipped with low-resolution DACs,combined with the OFDM technology,and based on the NP-hard hybrid discrete continuous least squares optimization method,CESLP precoding is proposed.Simulations show that this solution only uses DACs with a few bits of resolution,and can still achieve performance very close to the ideal CESLP precoding of infinite resolution DACs,which greatly reduces the overhead cost of the system.