面向大规模目标跟踪的多波束卫星天线自适应处理技术研究

The satellite communications industry is experiencing an exciting evolvement currently, which labeled as broadband, high throughput, as well as mobility. It reveals a promising future in this industry with a rapid worldwide uprising. However, there still are some issues remaining unsolved in satellite communications, such as the lower service quality of the users at the edge of spot beams. Meanwhile, satellite communications industry faces the turn around of its role, from a competitor of the terrestrial communications to its complement. In order to solve the above mentioned problem and help to fulfill the role change, a set of adaptive processing techniques is proposed in this project for the improvement of multi-beam satellite antenna, which based on the adaptive beam -forming and aiming at a large scale targets tracking. The research activities of this proposal will begin with theoretic analysis of the projection far-field of offset parabolic reflector with feeds array in focal or off focal. The adaptive beam-forming algorithm will be investigated and designed then for user tracking based on the above far-field analysis results of feeds array and offset parabolic antenna. Furthermore, the beam-schedule mechanism will be introduced and analyzed, and the relative algorithms will also be designed. After that, the implementation problems will be discussed, including the beam-forming network module, the adaptive coefficients generating module, as well as the beam schedule module, etc. Finally, the test-bed will be constructed using the implemented modules and the simulation soft-programs, and the validation of the proposed techniques will be verified on this test-bed. As a well known fact, the extent of satellite industry development in China is far behind those developed countries. Furthermore, it is necessary to speed up our satellite communications system construction to fill up the digital divide within our broad national territory. Nevertheless, the activities and outcomes of this research project will help us to occupy the high-land of satellite communications technology, and catch up with the pace of satellite communications industry of those developed countries, at least to some extent.

当前卫星通信发展具有宽带化、高速率、移动性等特点和趋势，并且呈现出高速发展的态势。然而宽带卫星通信仍存在着波束小区边缘用户服务质量低的问题，并且因为自身重新定位为地面通信的补充和延伸而面临系统转型的需求。本项目拟从多波束天线这一宽带卫星通信核心支撑技术入手，提出一种以自适应波束成形技术为基础、面向大规模目标跟踪的自适应处理技术方案，目的是为宽带卫星通信目前存在的问题和面临的需求提供一个有效的解决方案。本项目研究包括偏馈偏焦抛物面天线投射场分布理论分析、卫星多波束成形的快速自适应算法研究、多点波束成形的调度机制与算法研究及设计、大数目自适应波束成形网络实现方案设计、多波束天线自适应处理技术方案验证等内容。我国在卫星通信领域仍落后于国外先进水平，加快发展我国卫星通信具有必要性和迫切性，而相关的多波束天线技术研究成果，可以为我国在卫星通信领域抢占技术制高点，为迎头赶上国外先进水平创造有利条件。

当前卫星移动通信呈现出宽带化、高速率、移动性等特点和发展趋势。然而由于面临地面蜂窝移动通信的激烈竞争，卫星移动通信目前多应用于航空、航海、偏远地区及应急区域，表现出一定的用户稀疏、成簇的特点，采用传统的固定多波束覆盖方案存在着系统利用率不高、频率资源分配不灵活的缺点。为解决这一问题，本项目提出一种以自适应波束成形技术为基础、面向大规模目标跟踪的动态追踪波束覆盖方案。.本项目首先开展了波束合成基础理论及算法研究，对偏馈抛物面反射天线的二次辐射场进行了几何分析，建立了馈源阵列的空间辐射场合成数学模型，提出了一种多参考点变步长扩展LMS算法，可快速求解合成目标波束的馈源加权系数；对大规模追踪波束覆盖的系统架构方案进行了设计，提出了一种适合全覆盖域波束追踪的成形网络结构，设计了一种用于变换馈源组合的可编程开关阵列配置图案和配置方法；对追踪波束资源分配调度方案进行了研究，设计了合成波束追踪及拆分/合并准则，提出了基于合成波束中心最准原则的馈源组合选择方案，提出了一种有效提高利用率的波束主导全局资源分配调度方案；设计了一种可用于系统初始接入网部分的基于上行链路干扰抵消和下行链路干扰预抵消技术的准同频组网系统方案， 提出了基于组间调换和联盟博弈的两种资源调度算法，均可显著提升平均用户信干噪比和平均波束频谱效率等性能；设计实现了演示平台的软硬件构建方案，并验证了方案中自适应处理关键技术的可行性和有效性。.本项目所设计的基于动态追踪波束的卫星移动通信系统方案具有如下的优点：可取代传统系统中的移动性管理功能，在一定程度上降低通信体制设计复杂度；追踪波束主导的资源分配调度方案，无需采用传统的3/4/7色波束频率复用，可以显著提高频率资源的利用率；面向用户/用户群形成的追踪波束，有利于提高卫星移动通信系统QoS。总之，如后续具体工程实现问题能得到有效解决，本系统方案将能进一步展现出“用户为中心”的设计理念和应用价值。