In The Future Mobile Communication System More User Precoding And Scheduling Algorithm Research

MIMO has become to be the key physical technology in the current and futurecommunication system. Multi-user (MU) MIMO system realizes spatial divisionmultiple acess to communicate with several users within the same time slot and thesame frequency band. It greatly improves the spectral efficiency for its good channelorthogonality. At the same time, co-channel interference becomes the main factor indegrading the system performance, especially obvious for the downlink channel. Thus,from the angle of resource assignment and signal processing, scheduling and precodingschemes are needed to be designed for higher multi-user diversity gain and spatialmultiplexing gain, also including the CCI cancellation.Besides the limited feedback consumption and performance compromision,complexity and capacity are the main factors for designing the scheduling andprecoding shemes in multi-user MIMO system. Therefore, at the system model of singlecell MU-MIMO system, for the purpose of lowering algorithm complexity, novelscheduling and precoding schemes are proposed. Further, the channel modelingproblem at large antenna array is discussed explicitly. A generation of each chapter isdescribled in the following part.A concrete description about the research background and status is given in chapterI. Also it displays a structure diagram of the dissertation.In chapter II, a detailed research is made about the precoding technology in singlecell MU-MIMO systems. Firstly, several conventional precoding schemes are discussed.Based on the analysis, a new precoding scheme based on GSO is proposed. Besides thetheoretical deduction of algorithm, verification between the conventional scheme andnew scheme is done from the angle of algorithm complexity and system capacity. Bycontrast, we find that the new precoding algorithm can greatly lower the computationalcomplexity, while keep the same system capacity performance with other schemes.In chapter II, the scheduling scheme in single cell MU-MIMO systems is explored.Firstly, several conventional scheduling schemes are discussed under TDD mode. Theyare scheduling schemes based on capacity, channel energy, and lower bound of system capacity respectively. Based on these, a new scheduling scheme also based on the lowerbound is proposed with much better performance. By verification, the new schedulingscheme can greatly lower the algorithm with little capacity loss.In chapter IV, MU-MIMO technology at large scale antennas is explored. Firstly,the mutual coupling among antennas is discussed. Based on these, the new MIMOchannel modeling is done under large scale antenna deployment. At last, a contrastabout the system capacity is made at different antenna deployment. Simulation resultsshow that the mutual coupling between antennas is an important factor in channelmodeling.In chapter V, a conclusion about the dissertation and the future research points aregiven.