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arXiv · 2412.20920

Channel Charting-assisted Non-orthogonal Pilot Allocation for Uplink XL-MIMO Transmission

Haohong Che·Li You·Jue Wang·Zhenzhou Jin·Chenjie Xie·Xiqi Gao
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Abstract

Extremely large-scale multiple-input multiple-output (XL-MIMO) is critical to future wireless networks. The substantial increase in the number of base station (BS) antennas introduces near-field propagation effects in the wireless channels, complicating channel parameter estimation and increasing pilot overhead. Channel charting (CC) has emerged as a potent unsupervised technique to effectively harness varying high-dimensional channel statistics to enable non-orthogonal pilot assignment and reduce pilot overhead. In this paper, we investigate near-field channel estimation with reduced pilot overhead by developing a CC-assisted pilot scheduling. To this end, we introduce a polar-domain codebook to capture the power distribution of near-field XL-MIMO channels. The CC-assisted approach uses such features as inputs to enable an effective low-dimensional mapping of the inherent correlation patterns in near-field user terminal (UT) channels. Building upon the mapped channel correlations, we further propose a near-field CC-assisted pilot allocation (NCC-PA) algorithm, which efficiently enhances channel orthogonality among pilot-reusing UTs. Numerical results confirm that the NCC-PA algorithm substantially elevates the wireless transmission performance, offering a marked improvement over the conventional far-field CC-PA approach.

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Haohong Che, Li You, Jue Wang, Zhenzhou Jin, Chenjie Xie, Xiqi Gao. 2024-12-30. Channel Charting-assisted Non-orthogonal Pilot Allocation for Uplink XL-MIMO Transmission. https://arxiv.org/abs/2412.20920

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