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arXiv 2405.04027eess.SP
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基于交替最大后验概率的XL-MIMO系统可见区域联合检测与信道估计

Joint Visibility Region Detection and Channel Estimation for XL-MIMO Systems via Alternating MAP

Wenkang Xu, An Liu, Min-jian Zhao

AI总结:

针对XL-MIMO系统近场非平稳场景下的可见区域检测与信道估计问题,提出结合二维马尔可夫先验的交替MAP框架,含三个模块,仿真验证其性能优势。

摘要:

本文研究了存在近场传播与空间非平稳效应的超大规模多输入多输出(XL-MIMO)系统中的可见区域(VR)联合检测与信道估计问题。在该场景下,每个散射体仅能被部分天线接收,即其在天线上存在特定的可见区域。由于相邻子阵间存在空间相关性,散射体的可见区域呈现二维(2D)簇稀疏性。本文设计了一种二维马尔可夫先验模型以捕获这种结构化稀疏性。在此基础上,提出了一种新型交替最大后验概率(MAP)框架,用于实现高精度的可见区域检测与信道估计。该交替MAP框架包含三个基本模块:信道估计模块、可见区域检测模块与网格更新模块。具体而言,第一个模块是低复杂度的无逆变分贝叶斯推理(IF-VBI)算法,通过最小化松弛的库尔贝克-莱布勒(KL)散度避免矩阵求逆;第二个模块是结构化期望传播(EP)算法,能够处理复杂的先验信息;第三个模块通过梯度上升优化极域网格参数。仿真结果表明,所提算法在可见区域检测与信道估计两方面均具有优越性能。

英文摘要:

We investigate a joint visibility region (VR) detection and channel estimation problem in extremely large-scale multiple-input-multiple-output (XL-MIMO) systems, where near-field propagation and spatial non-stationary effects exist. In this case, each scatterer can only see a subset of antennas, i.e., it has a certain VR over the antennas. Because of the spatial correlation among adjacent sub-arrays, VR of scatterers exhibits a two-dimensional (2D) clustered sparsity. We design a 2D Markov prior model to capture such a structured sparsity. Based on this, a novel alternating maximum a posteriori (MAP) framework is developed for high-accuracy VR detection and channel estimation. The alternating MAP framework consists of three basic modules: a channel estimation module, a VR detection module, and a grid update module. Specifically, the first module is a low-complexity inverse-free variational Bayesian inference (IF-VBI) algorithm that avoids the matrix inverse via minimizing a relaxed Kullback-Leibler (KL) divergence. The second module is a structured expectation propagation (EP) algorithm which has the ability to deal with complicated prior information. And the third module refines polar-domain grid parameters via gradient ascent. Simulations demonstrate the superiority of the proposed algorithm in both VR detection and channel estimation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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