论文标题
幅度和相位估计，用于绝对校准大型MIMO前端
Amplitude and Phase Estimation for Absolute Calibration of Massive MIMO Front-Ends
论文作者
论文摘要
相对于传统多源系统，大量多输入多输出（MIMO）有望明显更高的性能。但是，大规模的MIMO系统的承诺收益在很大程度上依赖于绝对前端校准的准确性，以及基站（BS）的通道估计质量。在本文中，我们分析了用户设备的校准机制，以估计每个射频链与BS阵列接口的幅度缩放和相位漂移。假设在BS和Ricean褪色处具有均匀的线性阵列，我们获得了具有矩基（振幅，相位）和最大样品（仅相位）估计技术的估计参数。与以前的作品形成鲜明对比的是，我们在数学上阐明了两种方法的等效性以进行相估计。此外，我们严格地得出Cramer-Rao的下限，以表征两个估计量的准确性。通过数值模拟，我们通过不同的占主导地位线力，主要的到达角度和信噪比来评估估计器性能。
Massive multiple-input multiple-output (MIMO) promises significantly higher performance relative to conventional multiuser systems. However, the promised gains of massive MIMO systems rely heavily on the accuracy of the absolute front-end calibration, as well as quality of channel estimates at the base station (BS). In this paper, we analyze user equipment-aided calibration mechanism to estimate the amplitude scaling and phase drift at each radio-frequency chain interfacing with the BS array. Assuming a uniform linear array at the BS and Ricean fading, we obtain the estimation parameters with moment-based (amplitude, phase) and maximum-likelihood (phase-only) estimation techniques. In stark contrast to previous works, we mathematically articulate the equivalence of the two approaches for phase estimation. Furthermore, we rigorously derive a Cramer-Rao lower bound to characterize the accuracy of the two estimators. Via numerical simulations, we evaluate the estimator performance with varying dominant line-of-sight powers, dominant angles-of-arrival, and signal-to-noise ratios.
