While commercial deployment of 6G communications systems is not expected until the end of the decade, work is well underway in laboratories worldwide to have the essential fundamental equipment on which such infrastructures will be based. Looking to take a lead in the new arena, Japanese operator NTT Docomo is acting with tech firms NTT Corp, NEC and Fujitsu to jointly development a top-level wireless device capable of ultra-high-speed 100 Gbps transmissions in the 100 GHz and 300 GHz sub-terahertz bands.
Putting their work into context, the firms said that in the 6G era, wireless networks will likely support applications ranging from ultra HD video streaming to real-time control in autonomous vehicles, as well as increasing communication demands.
High-capacity wireless communication is expected to be achieved by exploiting the abundant bandwidth available in the sub-terahertz band from 100 GHz to 300 GHz. Yet compared with 28 GHz and other millimetre bands used in current 5G systems, the much higher frequencies of the sub-terahertz band will require entirely different wireless devices that are now being developed from scratch.
The partners in this new project said that this effort will need to overcome several key challenges to be successful, such as determining the specific performance requirements of wireless devices operating in the sub-terahertz band, and then actually developing such devices.
At the heart of the first fruits of this partnership is the R&D work the four companies have been conducting on sub-terahertz devices since 2021 in anticipation of the coming 6G era. To date, tests of a jointly developed wireless device have achieved ultra-high-speed 100 Gbps transmissions in the 100 GHz and 300 GHz bands at distances of up to 100 metres. 100 Gbps is a key benchmark for mobile communications. It is approximately 20 times faster than the maximum 4.9 Gbps data rate of current 5G networks.
Looking at the roles and achievements of the four individual organisations, Docomo has analysed the wireless system configuration and performance required for 100 GHz telecommunications applications and has developed wireless transmission equipment capable of transmitting data rates equivalent to 100 Gbps at a distance of 100 metres.
NTT has conducted research into 300 GHz wireless devices and related equipment such as wideband mixers and has developed a top-level wireless device capable of transmitting 100 Gbps per channel at a distance of 100 metres in the 300 GHz band.
After analysing a wireless system configuration for telecommunications in the 100 GHz band, NEC has developed a multi-element active phased array antenna (APAA) consisting of more than 100 antenna elements.
After researching compound semiconductor technologies that enable high-output, high-efficiency signal amplification to extend communication range and reduce power consumption in the 100 GHz and 300 GHz bands, Fujitsu said it has achieved the world’s highest power efficiency in a high-output amplifier under specific high-power conditions in the spectrum band as of March 2024.
Going forward, the four companies said they will continue to conduct extensive R&D into sub-terahertz telecommunications, using each company’s strengths in various initiatives to contribute to 6G standardisation.