Coded Spatial Random Access in the Near Field

Massive machine-type communications are transforming the Industrial Internet of Things (IIoT) by enabling seamless connectivity among a vast number of devices. To efficiently manage the resulting sporadic and large-scale traffic, grant-free random-access protocols, particularly coded random access (CRA), have emerged as scalable and reliable solutions. Meanwhile, advancements in extremely large-scale MIMO and high-frequency communications (e.g., mmWave, THz) are pushing networks into the near-field regime, enhancing spatial multiplexing and connectivity. In this paper, we propose a novel coded spatial random access (CSRA) scheme that leverages an extremely large aperture array (ELAA) at the access point (AP) to exploit near-field spatial multiplexing for grant-free massive access in IIoT systems. Unlike conventional approaches, CSRA eliminates the need for complex channel estimation by integrating CRA with successive interference cancellation and the spatial multiplexing capabilities of the near-field regime. This enables improved reliability and scalability, making CSRA a promising solution for next-generation wireless networks.