Electromagnetic Information Theory: Fundamentals and Applications for 6G Wireless Communication Systems

TL;DR

This work argues that 6G requires a unified framework that bridges electromagnetic theory and information theory through antenna and propagation-channel modeling, resulting in electromagnetic information theory (EIT). It contends that continuous-space, non-stationary channels in space-air-ground-sea networks and technologies like holographic MIMO, ISAC, and RIS necessitate continuous CSI and end-to-end capacity analyses beyond classical theories. The paper outlines a concrete integration strategy (twinning EM and IT, increasing capacity, accomplishing channel modeling, and guiding antenna design) and demonstrates how this framework can yield improved channel estimation, more accurate capacity bounds, and better-informed 6G system designs. Overall, EIT provides a principled basis for analyzing and optimizing 6G wireless networks with global coverage and advanced propagation environments.

Abstract

In wireless communications, electromagnetic theory and information theory constitute a pair of fundamental theories, bridged by antenna theory and wireless propagation channel modeling theory. Up to the fifth generation (5G) wireless communication networks, these four theories have been developing relatively independently. However, in sixth generation (6G) space-air-ground-sea wireless communication networks, seamless coverage is expected in the three-dimensional (3D) space, potentially necessitating the acquisition of channel state information (CSI) and channel capacity calculation at anywhere and any time. Additionally, the key 6G technologies such as ultra-massive multiple-input multiple-output (MIMO) and holographic MIMO achieves intricate interaction of the antennas and wireless propagation environments, which necessitates the joint modeling of antennas and wireless propagation channels. To address the challenges in 6G, the integration of the above four theories becomes inevitable, leading to the concept of the so-called electromagnetic information theory (EIT). In this article, a suite of 6G key technologies is highlighted. Then, the concepts and relationships of the four theories are unveiled. Finally, the necessity and benefits of integrating them into the EIT are revealed.

Figures (5)

• Figure 1: Relationships and gaps between electromagnetic theory, information theory, wireless propagation channel modeling theory, and antenna theory.
• Figure 2: Capacity of the continuous-space electromagnetic channel.
• Figure 3: The description of the wireless propagation channel and radio channel.
• Figure 4: The impact of mutual coupling and reactance on channel capacity of the radio channel model.
• Figure 5: The description of the traditional antenna theory and wide-sense antenna theory.