About this Research Topic
Despite the successful roll-out of fifth-generation (5G) wireless networks with a high-frequency millimeter-wave (mmWave) spectrum, the quest for increasing data rates persists. Towards this end, higher frequencies over the terahertz (THz) band (0.1-10 THz) will be central to ubiquitous wireless communications in beyond-5G or sixth generation (6G) networks. In particular, THz frequencies promise to support ample spectrum, above hundred Gigabitper-second (Gbps) data rates, massive connectivity, denser networks, and highly secure transmissions. Multiple leading 6G initiatives probe THz communications, including the ``6Genesis Flagship Program (6GFP)", the European Commission’s H2020 ICT-09 THz Project Cluster, and the “Broadband Communications and New Networks" in China. In the US, THz technology was identified in 2014 by the US Defense Advanced Research Projects Agency (DARPA) as one of the four major research areas that could have an impact on society larger than that of the Internet itself. Similarly, the US National Science Foundation and the Semiconductor Research Consortium (SRC) also identify THz as one of the four essential components of the next IT revolution.
The THz spectrum is sandwiched between the mmWave and the far-infrared (IR) bands and has, for long, been the least investigated electromagnetic spectrum. However, recent advancements in THz signal generation, modulation, and radiation methods are closing the so-called THz gap. The THz band offers much higher transmission bandwidths compared to the mmWave band and more favorable propagation settings compared to the IR band; it can thus complement the conventional radio-frequency spectrum. Several unique challenges, however, have still to be addressed to achieve the full potential of THz communications. For instance, THz transmissions incur very high propagation losses, which significantly limit the communication distances. Hence, while in aerial, satellite, and vehicular networks, THz frequencies can provide low-latency communication, the propagation losses can hinder the gains. Furthermore, the coexistence of mmWave, sub 6GHz, and optical wireless communications and networking is not yet fully understood. THz communications will be complemented by enablers at both the infrastructure and algorithmic levels. At the infrastructure level, emerging beyond-5G technologies such as reconfigurable intelligent surfaces, ultra-massive MIMO configurations, and integrated access and backhaul, can boost the gains of THz communications. At the algorithmic level, novel signal processing techniques and networking protocols can get around the THz quasi-optical propagation characteristics and mitigate microwave characteristics to enable seamless connectivity. Efficient THz baseband signal processing can further reduce the gap between the huge available bandwidths and the limited state-of-the-art frequency sampling speeds. This research topic is therefore devoted to investigating the role of key 6G enabling techniques in fostering THz communication and vice versa.
High-quality technical paper submissions reporting on original theoretical, numerical, and experimental results are welcome. Exceptional survey/tutorial-like papers may also be considered. We solicit original submissions in the following areas:
• THz channel, noise, and other impairments modelling
• Interference modelling and analysis in the THz spectrum
• Resource allocation in the THz spectrum (beamforming, power control, base-station association, scheduling, cache placement, etc.)
• THz network deployment and optimization (channel access strategies, cell and user discovery)
• THz-enabled mobile edge computing
• THz-assisted vehicle-to-everything (V2X) networks
• Relaying in THz networks
• MIMO-enabled THz communications (ultra-massive MIMO, cell-free MIMO, holographic radio, etc.)
• Reconfigurable surface-assisted THz communications
• High-rate and low-complexity THz physical layer designs (Analog, digital, and hybrid THz architectures)
• THz-specific modulation and waveform design
• Efficient THz baseband signal processing (detection, coding, channel estimation, etc.)
• Joint THz communications, sensing, imaging, and localization
• Machine learning for THz communications
• THz-based nanoscale networking
• Terahertz experimental test-bed
Keywords: 6G, Terahertz Communications, Terahertz Networking, Terahertz Signal Processing, Ultra-massive MIMO
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.
