Researchers have developed a way to make terahertz frequency communication possible by upgrading the modulation techniques.
With the introduction of the 5G technology, there is new question as well as a curiosity for expanding the technology standard for broadband cellular networks (5G). Engineers worldwide are now working on systems that could further speed up communications. The next-generation wireless communication networks, from 6G onward, will require technologies that enable communications at sub-terahertz and terahertz frequency bands (i.e., from 100GHz to 10THz).
The team aimed to demonstrate the feasibility of communication links at frequencies above 100 GHz, for ranges over 1 km rand at data rates higher than 1 Gbps. The system they proposed exceeded their expectations, enabling communications at a range over 2km and with a data rate of over 1 Gbps.
Researchers say that the key novelty which makes their system unique is the way they modulate the terahertz carrier signal with the information for transmission. Unlike the traditional systems, which includes a mixer (the device used to add the information to the signal) is present at the transmitter right after the frequency multipliers that upconvert a lower-frequency signal to the terahertz band and before the antenna, this system has the power enough to blow up the mixer.
To overcome the power-related challenges associated with the problem they were tackling, Dr. Thawdar, Dr. Jornet and their colleagues tested two plausible solutions. The first entailed modulating the local oscillator in their system and then upconverting it to terahertz frequencies, while the second involved the modulation while the signals were half-way, through a so-called frequency multiplication process.
Both these strategies allowed them to add information and retain their desired maximum output power. Their only additional requirement was to carry out additional signal processing to pre-compensate for the distortion introduced by frequency multipliers.
These results can establish exciting possibilities for communications at extremely high frequency bands. In the future, this work could inspire the study of even more challenging applications, such as the use of terahertz communications for satellite and space links.
Reference : Priyangshu Sen et al, Multi-kilometre and multi-gigabit-per-second sub-terahertz communications for wireless backhaul applications, Nature Electronics (2022). DOI: 10.1038/s41928-022-00897-6.