随着我国海洋经济迅猛发展，海域宽带无线通信需求日益增长，而传统岸基无线通信技术难以满足其远距离、广覆盖的需求。大规模MIMO技术可灵活实现强指向性窄波束，从而有效增强目标方向的覆盖，因此，本项目拟开展基于岸基大规模MIMO基站的近海宽带无线传输关键技术研究。海域无线信道散射稀疏、用户分布稀疏、基站布设稀疏；此外，海域用户类型、需求、信道复杂多样，呈现出较大的差异性。以上与陆地传播环境不同的典型特点使现有面向陆地的大规模MIMO技术不能适用于海域场景。为此，本项目首先建立挖掘海域无线传播特性的视距、超视距信道模型以及海域大规模MIMO信道模型。在此基础上，研究用户位置信息、统计信道信息与波束角度域之间的关系，探索不同海域信道特性下的混合波束成形技术，设计低复杂度波束跟踪与预测方案，最终从角度域构建统一的波束管理框架，为实现广域灵活覆盖的岸基宽带无线通信系统打下理论基础。

With the rapid development of the marine economy, it has encountered ever-growing in the demand of broadband wireless communications in marine areas. However, the traditional terrestrial cellular wireless communication system cannot guarantee long-distance and wide-area coverage required by maritime communications. Since the massive multiple-input multiple-output (MIMO) technology can flexibly form a narrow beam with strong directivity and enhance the coverage in the target direction, we aim to study the key technologies of the offshore broadband wireless transmission based on shore-based massive MIMO base stations. The maritime propagation environment shows obvious difference as compared to that inland, such as the sparsity in the scattering environment, the user distribution, and the base station deployment. In addition, the requirement of services, the channel condition, and the accuracy level of channel state information (CSI) largely vary among different maritime users. These render the currently adopted terrestrial massive MIMO technologies cannot be applied to the maritime scenario directly. To this end, we firstly establish wireless channel models for the maritime line-of-sight and beyond-line-of-sight propagations, as well as the corresponding massive MIMO channel model. Based on the established models, we further reveal the relationship between the user location (or the statistical CSI) and the angle domain. Specifically, using the information in the angle domain, we explore novel low-cost hybrid beamforming techniques for the different maritime propagation scenarios, design low-complexity beam tracking and prediction schemes, and finally establish a unified beam management framework. The proposed algorithms form essential components in building up a practical shore-based broadband wireless communications system with a flexible wide-area coverage.