Abstract
In preparation for the 6th generation (6G) of communication networks, the adoption of high-frequency spectrum
in millimeter wave (mm-wave) and terahertz (THz) frequencies
is expected to improve communication bandwidth, bolster capacity, and decrease latency. However, challenges such as high
propagation losses and the need for direct line-of-sight (LoS)
connections between base station (BS) and user equipment (UE)
pose significant barriers to the deployment of mm-wave-based
systems. Within this context, integrated sensing and communication (ISAC) and reconfigurable intelligent surfaces (RISs)
have recently emerged as the key enabling technologies for highfrequency systems deployment. However, the fundamental tradeoff between sensing and communications in ISAC has already
been introduced in the literature, unveiling the inevitable resource
competition between sensing and communication tasks. This
paper explores the use of orbital angular momentum (OAM) to
distinguish the sensing signal, allowing for autonomous handling
of sensing operations, distinct from the linearly polarized communication signals. This framework uses wave domain computing
(WDC) to perform sensing tasks independently of the BS, thereby
reducing the computational load on the BS and enhancing the
response time and accuracy of sensing tasks. This is achieved
by processing the extensive data generated by high-frequency
networks directly on the physical layer of the metasurface.
This approach facilitates efficient environment mapping and
channel propagation path construction, addressing latency issues
inherent in previous systems. We also review the associated prestandardization and subsequent commercialization efforts for the
RIS and ISAC technologies that are taking place with the aim
of commercial deployments in future 6G networks by 2030.