Research On Signal Processing And Access Scheme Based On Beamforming

In the past three decades, from the traditional voice service to today's broadband data service, mobile communication is developing rapidly with each passing day and continuously changing people's life.Nowdays, the fifth generation mobile communication (5G), driven by mobile Internet and Internet of Things, has broad application prospects,and promotes a new wave of science and technology. 5G system, based on large-scale antenna technology, new multi-access technology,ultra-dense network technology and other wireless technologies, will fully meet the technical requirements of future mobile communications.Beamforming technology, as a core technology of large-scale antenna technology, will undoubtedly become one of the key technologies of 5G.Beamforming technology is a multi-antenna based signal processing technique in which the antenna gain is obtained by changing the weighting coefficients of the antenna array to produce directional beams.Beamforming has a great advantage in suppressing inter-cell interference and improving edge throughput performance.In this thesis, under the background of 5G key technology, we mainly focus on beamforming technology. Beginning with the principle and system model of beamforming, key technology of millimeter-wave beamforming based on 5Q beamforming algorithms and access schemes based on beamforming are studied. For beamforming algorithms, this thesis studies and simulates several typical beamforming algorithms for single-user multiple-input multiple-output (MIMO) systems, multi-user MIMO systems and massive MIMO systems and their respective performance enhancements. For the research of schemes, this thesis studies and analyzes the access schemes of massive MIMO system and media access control (MAC) layer in the IEEE 802.11 ah protocol for the Internet of Things. Furthermore, on the basis of beamforming technology,we improve the existing access schemes in the two systems. Compared with the original schemes respectively, the results show that the two improved schemes have certain improvement on the system performance and have great practical significance.