A Tutorial on Near-Field Driven 6G Networks

With the advancement in the technological architecture of Sixth Generation (6G) networks, near-field-driven designs have become increasingly prominent in wireless communications systems. This technological shift towards achieving efficient communication with enhanced performance has introduced a new research trend and opened problems in near-field communications. With the prime objective of highlighting these open research problems and subsequent challenges, this tutorial focuses on introducing the fundamental concepts and novel technological innovations in near-field-driven 6G networks. It accentuates the potential of the near-field communication systems to enhance localization precision, improve the beamfocusing for energyefficient transmission, and ability to unify various wireless subsystems, forming more advanced and integrated communication systems. Moreover, this tutorial also addresses open research problems in the areas mentioned to improve energy efficiency and system performance and focuses on practical implementation issues in these domains. Furthermore, in order to demonstrate the importance of near-field-driven designs, a subsequent simulation of a Quadrature Phase-shift Keying (QPSK)-modulated end-toend system is given, which highlights that the beamfocusing can lead to spatial separation of users, granting the beam-focusing vector two degrees of freedom.