At the 6-GHz Frontier: Towards Efficient Spectrum Sharing with Unlicensed Users
Researchers develop methods to enable unlicensed services make the most of the 6-GHz band without interfering with preexisting services
The sheer amount of data transmitted wirelessly in unlicensed frequency bands, such as those used by Wi-Fi, is causing spectral congestion. To alleviate this problem, many countries have allowed unlicensed use of the 6-GHz band provided it does not interfere with preexisting licensed services. Now, researchers from Korea have developed two complementary methods that allow unlicensed devices to utilize the newly opened frequency slots, paving the way to better 6-GHz Wi-Fi networks.
The past few years have seen a massive increase in wireless data transmission. The growing demand for video streaming services, video conferencing, and work-from-home opportunities following the COVID-19 pandemic is causing a problem known as “spectral congestion.” Put simply, when too many nearby devices communicate using the same range of frequencies, the resulting interference can greatly degrade service quality.
The negative effects of spectral congestion are particularly noticeable for services that operate using unlicensed spectrum, such as radio local area networks (RLANs) or, more commonly, Wi-Fi, which uses the 2.4-GHz and 5-GHz bands. To mitigate this problem, regulatory agencies in many countries have recently decided to open up part of the 6-GHz band for unlicensed access through spectrum sharing. In other words, RLAN devices are allowed to communicate in the 6-GHz band as a secondary service (SS). However, they must not interfere with preexisting primary services (PSs).
A key requirement for RLAN devices wanting to benefit from the new spectrum involves a consistent and fair sharing of the 6-GHz band with PSs. One way to achieve this is by using automated frequency coordination systems (AFCSs), which provide RLAN devices with spectrum sharing information (SSI). The SSI tells the devices what frequencies are available in their area in real time and how strongly they can transmit their own signals.
In a recent study published in ETRI Journal, a team of researchers from the Electronics and Telecommunications Research Institute, Korea, have developed two novel methods to calculate SSI in AFCSs. Both methods focus on protecting the PSs from potential interference caused by new unlicensed devices entering the 6-GHz band.
The first method is best suited in cases where the AFCS uses the same frequency channels as the RLAN specification. It calculates the maximum permissible transmitted power for entire RLAN channels. This means that RLAN channels that only partially overlap with PS channels may be unnecessarily limiting their transmitted power in regions that fall outside the overlap.
In contrast, the second method calculates the maximum permissible transmitted power for each unit bandwidth, i.e., over small divisions of the 6-GHz band. In cases of partial overlap, this approach is more suitable as it places higher emphasis on those regions of the available bandwidth that are not interfering with PSs. “Our analyses confirm that both methods should be supported in AFCSs so that any one of them can be selectively applied according to the operating conditions of each RLAN device,” highlights Dr. Jungsun Um, the lead author of the study.
The methods proposed in this study will hopefully lead to better spectrum sharing technologies for the next generation of Wi-Fi. “The 6-GHz band has a large bandwidth of up to 1.2 GHz that can accommodate many independent Wi-Fi channels,” explains Dr. Um. “This means that Wi-Fi access points will have opportunities to select channels not being used by other access points, improving performance for all.”
Be sure to stay tuned for future advances on the 6-GHz frontier!
Reference
Titles of original paper: Comparison of two methodologies on spectrum sharing information for unlicensed use in the 6-GHz band
Name of authors: Jungsun Um, Bongsu Kim, Igor Kim, Seungkeun Park
Affiliation: Radio Resource Research Team, Electronics and Telecommunications Research Institute
About Dr. Jungsun Um from Electronics and Telecommunications Research Institute, Korea
Jungsun Um is a principal research engineer at the Electronics and Telecommunications Research Institute (ETRI), Korea. He has worked on various fields relevant to spectrum sharing technologies, wireless communication systems, and interference analysis. Currently, he is involved with a project on broadcasting transmission schemes. In 2017, he received a PhD in electrical engineering from KAIST and BS and MS degrees in electronic and electrical engineering from Sungkyunkwan University, both in Korea.
