Near-Field Communications: A Tutorial Review

By Yuanwei Liu, Zhao-Jie Wang, Jiaqi Xu, Chongjun Ouyang, Xidong Mu, Robert Schober. IEEE Open Journal of the Communications Society, 2023

632 citations recorded by the source corpus.

Extremely large-scale antenna arrays, tremendously high frequencies, and new types of antennas are three clear trends in multi-antenna technology for supporting the sixth-generation (6G) networks. To properly account for the new characteristics introduced by these three trends in communication system design, the near-field spherical-wave propagation model needs to be used, which differs from the classical far-field planar-wave one. As such, near-field communication (NFC) will become essential in 6G networks. In this tutorial, we cover three key aspects of NFC. 1) Channel Modelling: We commence by reviewing near-field spherical-wave-based channel models for spatially-discrete (SPD) antennas. Then, uniform spherical wave (USW) and non-uniform spherical wave (NUSW) models are discussed. Subsequently, we introduce a general near-field channel model for SPD antennas and a Green’s function-based channel model for continuous-aperture (CAP) antennas. 2) Beamfocusing and Antenna Architectures: We highlight the properties of near-field beamfocusing and discuss NFC antenna architectures for both SPD and CAP antennas. Moreover, the basic principles of near-field beam training are introduced. 3) Performance Analysis: Finally, we provide a comprehensive performance analysis framework for NFC. For near-field line-of-sight channels, the received signal-to-noise ratio and power-scaling law are derived. For statistical near-field multipath channels, a general analytical framework is proposed, based on which analytical expressions for the outage probability, ergodic channel capacity, and ergodic mutual information are obtained. Finally, for each aspect, topics for future research are discussed.

Subfields: Aerospace Engineering, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/e2deb58b1a91ceb314122d2e5439a1c2a0bcc551

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Citations in the corpus

A Tutorial on Near-Field XL-MIMO Communications Toward 6G (2023, neutral): “The appealing beneﬁts of XL-MIMO have spurred active research recently, and several overviews [51], [64]–[69] and survey/tutorial [8], [28], [41], [70], [71] papers on XL-MIMO have appeared, which are summarized in Table I for ease of reference.”
Integrated Sensing and Communications: Recent Advances and Ten Open Challenges (2023, background): “We conclude by highlighting some of the open problems at a glance in Table IV again.”
A Tutorial on Extremely Large-Scale MIMO for 6G: Fundamentals, Signal Processing, and Applications (2023, background): “These new requirements have inspired novel application scenarios by extending conventional 5G eMBB, mMTC, and URLLC into their enhanced 6G counterparts: further eMBB, ultra-mMTC, and extensive variations of URLLC [9], [13].”