As a next-generation wireless communications technology, 6G will integrate sensing and communications functions. It will continue to use multiple frequency bands, spanning low-band, mid-band, and high-band spectrum. Among the high frequency bands and in addition to millimeter wave (mmWave), 6G will extend its reach to terahertz (THz) and even optical spectrum in certain home and industrial scenarios.
ISAC-OW technology can be naturally integrated into existing lighting and light display systems, making every lamp and every screen part of the 6G ISAC-OW system. Given the ultra-high communication bandwidth, ISAC-OW is also a potential candidate to achieve ultra-high throughput. Because of the gap between optical spectrum and conventional electromagnetic spectrum, there will be no electromagnetic interference in conventional radio frequency bands. ISAC-OW is especially suitable for electromagnetic radiation-sensitive environments, like smart healthcare and industrial manufacturing.
The sub-millimeter wavelength of the optical spectrum can achieve high-precision positioning and high-resolution imaging, which, when combined with the response of substances to the characteristics of light waves, will enable more precise and accurate health sensing and monitoring.
Vision and usage scenarios of ISAC-OW
The Huawei 6G Research Team made a key technology breakthrough with the research and prototype verification of the ISAC-OW system. The team's first ISAC-OW prototype implements integrated communication, positioning, and sensing in both architecture and capability. The prototype simulates a medical environment where robots are accurately sensed and localized through optical wireless links (such as visible light and infrared spectrum) and can be remotely commanded to pick up and carry objects. The optical links in the prototype also wirelessly transmit the real-time videos between robots and the controller at a high speed, achieving integrated sensing and communications. By detecting subtle facial color changes or abdominal fluctuations, the ISAC-OW prototype is able to contactlessly monitor a person’s heartbeat and breathing status in real time, with an accuracy equivalent to commercial smart watches.
ISAC-OW prototype
During the prototype development, the team made breakthroughs in key technologies such as distributed optical antenna for joint detection and transmission, integrated sensing and communication architecture, and high-precision Time of Flight (ToF) modeling analysis. For example:
- For simultaneous communications and localization, unified waveforms, hardware architecture, and signal processing algorithms jointly enable high-speed video transmission and centimeter-level precision of indoor localization. During localization, devices use enhanced reflecting surfaces to reflect optical signals from base stations without generating interference for other base stations. As synchronization is not required, base stations can measure phase differences to provide high-precision localization.
- For contactless health monitoring and considering the impact of the heartbeat on blood vessels in the face, the team has combined ToF modeling analysis and deep learning technologies to accurately detect subtle changes in the light intensity reflected by faces, so as to measure the heartbeat and breathing frequency. The latter can also be measured by abdominal fluctuations during breathing. Results show that this approach is comparable to commercial smart watches.
Outlook
Capitalizing upon the advantages of the optical spectrum, which include high bandwidth, line-of-sight transmission, no RF interference, and high energy efficiency, the ISAC-OW system creates a larger imagination space and a solid technical foundation for 6G applications.
The Huawei 6G Research Team will continue researching ISAC-OW technology, with the aim of providing the most advanced core technologies and solutions for future 6G scenarios such as holographic hospitals and industrial automation.
