论文标题
LEO卫星大量MIMO OFDM通信的频道估计
Channel Estimation for LEO Satellite Massive MIMO OFDM Communications
论文作者
论文摘要
在本文中，我们研究了低地球 - 轨卫星通信系统的大量多输入多输出正交频施加通道估计。首先，我们使用Angle-Delay域通道来表征空间频率域通道。然后，我们表明，如果使用相同试验的用户终端（UTS）的数组响应向量（UTS）是正交的，则可以将通道估计的渐近最小均值误差（MMSE）最小化。受此启发，我们设计了一种有效的基于图的试验分配策略，以增强渠道估计性能。此外，我们设计了一种新型的两阶段通道估计（TSCE）方法，其中在卫星处接收的信号被每个余车空间域处理，然后是每个用户频域处理。此外，每个UT的空间域处理被证明对所有子载波都是相同的，并且得出了每次累积空间空间域线性处理的渐近最佳矢量。频域处理可以通过快速Toeplitz系统求解器有效地实现。仿真结果表明，提出的TSCE方法可以以较低的复杂性来实现MMSE估计的近乎性能。
In this paper, we investigate the massive multiple-input multiple-output orthogonal frequency division multiplexing channel estimation for low-earth-orbit satellite communication systems. First, we use the angle-delay domain channel to characterize the space-frequency domain channel. Then, we show that the asymptotic minimum mean square error (MMSE) of the channel estimation can be minimized if the array response vectors of the user terminals (UTs) that use the same pilot are orthogonal. Inspired by this, we design an efficient graph-based pilot allocation strategy to enhance the channel estimation performance. In addition, we devise a novel two-stage channel estimation (TSCE) approach, in which the received signals at the satellite are manipulated with per-subcarrier space domain processing followed by per-user frequency domain processing. Moreover, the space domain processing of each UT is shown to be identical for all the subcarriers, and an asymptotically optimal vector for the per-subcarrier space domain linear processing is derived. The frequency domain processing can be efficiently implemented by means of the fast Toeplitz system solver. Simulation results show that the proposed TSCE approach can achieve a near performance to the MMSE estimation with much lower complexity.
