大规模MIMO系统中动态迁移导频分配

大规模多输入多输出(MIMO)技术是5G的关键技术之一,由导频资源有限引起的导频污染是制约其发展的主要瓶颈之一,为此必须对宝贵的导频资源进行合理地分配以减小导频污染。已有的导频分配方案大多考虑静态导频分配,无法很好地适应用户位置不断变化的移动通信环境。文章针对大规模MIMO系统中用户移动时的导频分配问题,提出了一种动态迁移导频分配方法。该方法在两个相邻时隙间仅针对移动幅度较大的用户进行额外的导频优化,根据分配方案选择一个用户与之进行导频交换,对于其他的用户不改变原分配导频。复杂度分析及仿真结果表明,该算法相较于传统的导频分配方法可以显著地降低计算复杂度,并且与传统的导频分配方法具有相近的频谱效率,具有较高的实用价值。

Dynamic Migration Pilot Allocation in Massive MIMO Systems

Massive Multiple-Input Multiple-Output(MIMO) is one of the key technologies in 5G. Pilot contamination, which is caused by limited number of pilots, has become an important bottleneck for the development of massive MIMO. In this respect, a reasonable pilot allocation should be designed for the valuable pilot resources to reduce the effect of pilot pollution. However, existing pilot allocation schemes mostly consider static pilot allocation, which are not well adapted to the mobile communication environment where user positions are constantly changing. In this paper, a dynamic migration pilot allocation algorithm is proposed for the problem of how pilots are dynamically allocated stepping with the movement of users in massive MIMO. According to pilot allocation algorithm, a user is selected to exchange pilots with the user who has migrated between two time slots and does not change the original allocation pilot for other users. The complexity analysis and simulation results show that the proposed algorithm can significantly reduce the computational complexity and have similar spectral efficiency comparing with the traditional pilot allocation method. Therefore, the proposed algorithm has a high practical significance.