Near-field wideband channel evaluation for incredibly massive MIMO

Incredibly massive multiple-input-multiple-output (XL-MIMO) at millimeter-wave (mmWave) and terahertz (THz) bands plays a crucial function in 6G networks for its severe high beamforming gain and plentiful spectrum resources.

To let loose the supremacy of XL-MIMO, precise channel evaluation is of fantastic significance to carry out effective precoding. As opposed to classical 5G enormous MIMO, channel estimate for high-frequency XL-MIMO in 6G deals with a severe difficulty of “near-field beam split.”

To elaborate, high-frequency XL-MIMO brings the qualitative paradigm shift from traditional far-field planar-wave interactions to its near-field spherical-wave equivalent. In addition, the ultra-large bandwidth at mmWave and THz make the electro-magnetic wavefront of various frequency elements vary from each other, causing the unwanted beam split impact. The coupling of near-field and beam split results generates an intricate structure of cordless channels, whose evaluation is intractable for existing approaches.

New research study, entitled “Near-Field Wideband Channel Estimation for Extremely Large-Scale MIMO,” was released in Science China Information SciencesIt is co-authored by Mr. Mingyao Cui (very first author) and Prof. Linglong Dai (matching author) from Tsinghua University, China.

In this post, a bilinear pattern detection (BPD) based method was proposed to precisely recuperate the high-frequency XL-MIMO channel. The bilinear pattern of the near-field beam split impact is exposed, which indicates that the sporadic assistance set of near-field channels in both the angle and range domains can be concerned as a direct function versus frequency.

This bilinear pattern is utilized to approximate the angle-of-arrival (AoA) and range criteria of each near-field course part by means of a customized at the same time orthogonal matching pursuit algorithm. Simulation results showed their plan is capable of accomplishing high channel estimate precision in all far-field/near-field/narrowband/ wideband conditions.

This paper supplies a service to carry evaluation in the existence of near-field beam split. It is anticipated that the bilinear pattern might be encompassed numerous near-field wideband interaction circumstances for resolving near-field beam split problems, such as reconfigurable smart surface area interactions and cell-free huge MIMO interactions.

More details: Mingyao Cui et al, Near-field wideband channel evaluation for exceptionally massive MIMO, Science China Information Sciences (2023 ). DOI: 10.1007/ s11432-022-3654-y