Terahertz (THz) transmission is a complementary wireless technology for communication networks, which allow high-speed wireless extension of the optical fibers for Beyond 5G.
Over the last years, the proliferation of wireless devices and the increasing number of high quality emerging wireless services have raised dramatically the demand for spectral bandwidth along with the requirement for high data rate transmission. While the wireless world is moving towards the 5G era and many technological advances have been proposed as promising enablers, such as massive MIMO, full duplexing, and mm-wave communications, there seem to be significant limitations in the capability to efficiently and flexibly handle the massive amount of QoS/QoE-oriented data that will be exchanged in a future Big-Data-driven society along with the super-high data rate and almost zero latency requirements. Thus, wireless Tbit/s communications and the supporting backhaul network infrastructure are expected to become the main technology trend within the next ten years and beyond.
Networks beyond 5G are envisioned to provide unprecedented performance excellence, not only by targeting data rates in the Terabit-per-second regime but also by inherently supporting a large dynamic range of novel usage scenarios and applications that combine these extreme data rates with agility, reliability, zero response time and artificial intelligence. Virtual presence, 3D printing, Cyber Physical Systems for Intelligent Transport and Industry 4.0 are only a few examples of several highly challenging anticipated use cases. Although 5G seems more than willing to embrace several game changing design principles, such as virtualisation, softwarisation and commoditisation of resources, in order to enhance scalability, flexibility and efficient resources use, it can be easily understood that fundamental performance limitations related to available bandwidth, transmission and processing delay and cost and energy consumption still define the envelope of 5G capabilities.
To break these barriers in networks beyond 5G, one needs to bring little explored resources and technologies to validation and exploitation.
Terahertz Wireless Communication is one of those technologies. In the future, the users in rural or remote regions, which are difficult to access (e.g. mountains, islands), should be connected with high data rates up to 10 Gbit/s per user. This is either infeasible or very costly when using solely optical fibre solutions. Terahertz transmission as a wireless backhaul extension of the optical fibres will be an important building block to face this challenge and guarantee high-speed internet access everywhere beyond 5G. Moreover, the increasing number of mobile and fixed users in the private sector as well as in the industry and the service sector will require hundreds of Gbit/s in the communication to or between cell towers (backhaul) or between cell towers and remote radio heads (fronthaul). In such scenarios, Terahertz Wireless Communication can also play an important role.
Furthermore, THz communications are expected to enable the seamless interconnection between ultra-high-speed wired networks, e.g., fibre optic links, and personal wireless devices, such as laptops and tablet-like devices, achieving full transparency and rate convergence between wireless and wired links. This will facilitate the use of bandwidth-intensive applications across static and mobile users, mainly in indoor and local access scenarios. Some specific applications are high-definition holographic video conferencing (virtual reality office) or ultra-high-speed wireless data distribution in data centers.
Finally, fully adopting digital networking in industry, commerce and public services, including traffic control and autonomous driving, remote health monitoring services, supply chain, security and safety procedures, large production sites automation and production lines, place stringent requirements for Tbps-class access subject to fast response constraints. These Cyber Physical Systems scenarios, describing the ‘true colours’ of what is commonly known as Tactile Internet, mainly challenge the capability of systems beyond 5G. In all the above scenarios, THz wireless is an attractive complementing technology to the less flexible and more costly optical fibre connections and to the lower data rate wireless technologies (Visible Light Communication, mmWave, WiFi).