Key Enabling Technologies for the Post-5G Era: Fully Adaptive, All-Spectra Coordinated Radio Access Network with Function Decoupling

With the rapidly growing bandwidth demand for wireless applications, new system technologies related to post-5G are emerging. In this article, an all-spectra fully adaptive and coordinated radio access network (RAN) is reported and discussed. By employing a fiber-wireless integration and networking architecture, all data-carrying channels could be aggregated in the same fiber access infrastructure. This enables a coordinated RAN with function decoupling, in which lower RF, 5G New Radio (NR), sub-THz, and even lightwave are employed; also, different types of services are delivered depending on their physical layer properties. Promising scenarios are discussed, such as integrated access of wireless NR-free space optical (FSO) backhauling and indoor systems via visible light communication (VLC) and efficient NR beamforming aided by VLC positioning system. The former use case can enhance the network throughput and reliability. This is because both FSO and NR can support high channel capacity due to their abundant bandwidth. Meanwhile, with the advancement of novel DSP techniques, the stability of the NR-FSO link under diverse weather turbulences or suffering from burst mode interference can be enhanced. The latter scenario provides an alternative solution for high-speed data link and a simplified beam management via the VLC-aided positioning system. VLC can concurrently provide ubiquitous indoor illumination, data transmission, and positioning. With the help of artificial intelligence algorithms, a VLC-based precision positioning system can provide a location accuracy of less than 1 cm, and it is able to meet the narrow beam size of the NR beamformer in a 3D model. Therefore, it is foreseeable that an all-spectra function decoupled RAN can serve as a unified network platform to support all wireless applications while optimizing system throughput, channel condition, network coverage, and software/hardware complexity for post-5G mobile data networks.