February 4, 2020
FWCC Webinar Recap: Potential problems permitting unlicensed RLAN operations in the 6 GHz band
As many readers are aware, the FCC issued a notice of proposed rulemaking (NPRM) regarding RLAN operation within the 6 GHz bands. Over the last two and a half years, the FWCC has dedicated itself to protecting fixed links from t in these bands. Understandably so, this is especially important given the diversity of fixed link users in the 6 GHz bands; among others, utility companies, oil and gas companies, and local government agencies, including those dealing with public safety, have large numbers of 6 GHz links that perform unique and crucial tasks. There are approximately 97,000 fixed links in the 6 GHz bands.
On January 16th, the FWCC hosted an educational webinar regarding this NPRM with lawyers from Fletcher, Heald, and Hildreth presenting. The webinar attracted 135 attendees. Don Evans, an attorney with Fletcher, Heald, and Hildreth, said, “We were very pleased by the size and diversity of the companies and institutions that participated in the webinar. We had representatives of large and small wireless carriers, electrical utilities, public safety offices, railroads, petroleum companies, and consultants. We hope we were able to offer insight into the problem posed by the proposal to allow unlicensed, uncontrolled RLAN operations in the 6 GHz band.”
The webinar explained that the rules around 6 GHz RLAN use are still being debated at this time. Automatic Frequency Control (AFC) is particularly contentious as it increases RLAN costs but is required to protect fixed links fully. AFC requires the RLAN to send its location before transmitting and the RLAN location is then checked against a database to establish if the RLAN is in an exclusion zone. If the RLAN is in an exclusion zone, AFC assigns only non-interfering transmit frequencies to the RLAN. The RLAN community is currently pressing hard for FCC rules that allow unlicensed, non-AFC RLANs on the basis that the risk of interference to fixed links is low. The vast number of 6 GHz RLANs that are expected to be in use (958,062,017) means that even a low probability of interference from each RLAN equals near certainty of interference to some fixed links. AFC is vital for the guaranteed protection of the fixed links in these bands. The FWCC has been shining a light on arguments made by RLAN proponents that misunderstand or misrepresent the characteristics of fixed links, the way these paths are planned and how interference may occur. RLAN proponents often, for example, use RLAN power figures that are averaged over time which does not account for instantaneous power that may cause a fixed link to experience intermittent interference. In recent filings, the RLAN proponents have also argued that fade margin is something that can protect fixed links against interference from RLANs, “virtually all links have greater margin than required to achieve their availability design target.” The FWCC has explained in its filings that fade margin is needed for fixed links to cope with atmospheric fades and that there is no excess fade margin that can cater for interference from RLANs.
How to ensure your voice is heard
You may be wondering what you can do to ensure that your voice is heard concerning important topics such as AFC. Aviat urges you to file comments individually or become a member of the FWCC to bolster its efforts and funding. Here is how to file comments with the FCC:
- Visit www.fcc.gov/ecfs/filings
- When filing, enter both dockets 18-295 and 17-183 (press Enter after each)
- Type of filing will be “Letter“
- The address will be yours so select “Filer“
- Complete the form with your contact information
- Upload your letter
- Click Review then click Submit
What is the FWCC?
Aviat has been a supporter and member of the Fixed Wireless Communications Commissions (FWCC) since its founding in 1998. The FWCC is important as it speaks for the fixed service community before several U.S. government agencies, including the FCC and NTIA. The work that the FWCC undertakes is vital to ensuring that the interests and technical requirements of the fixed service are never overlooked. Their work is key to ensuring that fixed links are protected from harmful interference as new services are introduced in bands used by fixed links, or within adjacent bands. Indeed, the FWCC has been instrumental in many advances in the fixed service too; larger channel sizes and smaller minimum antenna sizes in some FCC bands, for example, are the result of the FWCC’s work and dedication to the fixed service.
Visit the FWCC website for more information