Location-Aided Pilot Contamination Avoidance for Massive MIMO Systems
Location-Aided Pilot Contamination Avoidance for Massive MIMO Systems
复制标题
DOI：
10.1109/twc.2018.2800038
复制
发表时间：
2016-10
影响因子：
10.4
通讯作者：
L. S. Muppirisetty;Themistoklis Charalambous;J. Karout;Gábor Fodor;H. Wymeersch
中科院分区：
文献类型：
--
作者：
L. S. Muppirisetty;Themistoklis Charalambous;J. Karout;Gábor Fodor;H. Wymeersch
导频污染是指在信道估计过程中由于相邻小区重复使用相同的导频序列而产生的干扰，它会严重降低大规模多输入多输出系统的性能。在本文中，我们提出了一种基于位置的方法来减轻上行链路多输入多输出系统的导频污染问题。我们的方法利用移动的设备的近似位置来提供移动的设备与其对应的基站之间的信道统计的良好估计。具体而言，我们的目标是避免导频污染，即使当基站天线的数量不是很大，当来自不同小区的多个用户，甚至在同一个小区，被分配相同的导频序列。首先，我们根据基站天线的数量和目标用户的位置来表征服务基站处的目标用户的期望角区域，并且观察到在该区域中由于空间可分性，干扰接近于零。其次，基于这一观察，我们提出了多用户多小区场景的导频协调方法，以避免导频污染。数值结果表明，所提出的导频污染避免方案提高了信道估计的质量，从而提高了目标基站提供的每小区和速率。
Pilot contamination, defined as the interference during the channel estimation process due to reusing the same pilot sequences in neighboring cells, can severely degrade the performance of massive multiple-input multiple-output systems. In this paper, we propose a location-based approach to mitigating the pilot contamination problem for uplink multiple-input multiple-output systems. Our approach makes use of the approximate locations of mobile devices to provide good estimates of the channel statistics between the mobile devices and their corresponding base stations. Specifically, we aim at avoiding pilot contamination even when the number of base station antennas is not very large, and when multiple users from different cells, or even in the same cell, are assigned the same pilot sequence. First, we characterize a desired angular region of the target user at the serving base station based on the number of base station antennas and the location of the target user, and make the observation that in this region the interference is close to zero due to the spatial separability. Second, based on this observation, we propose pilot coordination methods for multi-user multi-cell scenarios to avoid pilot contamination. The numerical results indicate that the proposed pilot contamination avoidance schemes enhance the quality of the channel estimation and thereby improve the per-cell sum rate offered by target base stations.