Research On Large Scale MIMO Codebook Technologies

Wireless communication technology has got rapid development in recent years, especially after the 4G technology has been applied. At the same time, the users put forward higher requirements for mobile broadband access, as well as the network data traffic will appear blowout situation in the future. So the study of 5G inevitably must put on the agenda. Among 5G technology, the large-scale MIMO technology because of its many sending antenna, system can obtain higher link reliability and data transfer rate, so it become one of the candidate technologies of next generation mobile communication systems.At the same time, due to the increase of the number of antennas, the large scale MIMO system technology has bigger challenge. For example, the large scale MIMO system put forward higher requirements for pre coding performance, it is necessary to research the codebook matrix that has better channel capacity and bit error rate performance. In addition, due to the huge number of single base station antennas, the large scale MIMO system will use the rectangular or 3D antenna array. In this case, the system needs the codebook design scheme that will be more suitable to the rectangular antenna array than original linear code. Under the background, in this paper, we focus on the large scale MIMO precoding and codebook design technology, and then put forward some codebook suitable for large-scale MIMO system. [1] We put a brief introduction to the advantages and the problem that need to be[1] We put a brief introduction to the advantages and the problem that need to be solved of the large scale multi-input multi-output(MIMO) system. Then the key technology of large scale MIMO system, such as channel capacity is analyzed, and emphatically introduces the limited feedback precoding technique, comparison and analysis of several classic codebook designs.[2] Through the analysis of the unitary matrix disturbance, this paper puts forward the hierarchical codebook scheme based on unitary matrix perturbation. It has two schemes, one is based on fourier perturbation hierarchical codebook, and the other is based on rotation matrix perturbation hierarchical codebook. At the same time, this paper proposes an adaptive subcodebook selection algorithm, when it does not meet some condition, the feedback of subcodebook PMI was carried out, just for the main codebook. Through the algorithm, we can solve the problem that the system feedback overhead is too large. The simulation results show that theproposed hierarchical codebook has performance gain to the single codebook, and it can effectively reduce the feedback overhead.[3] In large scale multi-input multi-output(MIMO) system, due to its huge size of antenna number, a rectangular antenna configuration or 3d configuration mode will be used. In this case, the original linear codebook is not applicable. Aiming at the situation, through the study of the channel correlation matrix of rectangular antenna array, this paper put forward a codebook used the Kronecker approximation theory that can be used in the rectangular antenna configuration system. The scheme is based on double codebook, and the simulation shows that this scheme, compared to the linear codebook, can be more adapted to the planar antenna configuration.