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.”

Webinar Recap

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.