Concerned that wireless devices might interfere with its cable TV set-top boxes Cisco asked the FCC today to consider all possible alternatives before it decided how to regulate the use of such devices operating in television white spaces.

Specifically, Cisco suggested that the FCC consider notching television channels 2 through 6 to prevent any wireless devices from using them. Wireless LAN (WLAN) devices operating on those channels could interfere with cable set-top boxes, which operate on channels 3 and 4 even in areas where no broadcaster is licensed to use them. 

Cisco first entered the cable set-top box market when it purchased Scientific-Atlanta in 2005.

Cisco also asked the FCC to consider “all possible technological choices available” to the commission, including the nearly completed 802.11y standard. According to Cisco, the 802.11y protocol calls on operators to resolve interference between WLAN devices and television broadcasting, and lets the operator shut down any interfering devices. Additionally, it said the 802.11y standard mandates that all WLAN devices be enabled by a station controlled by licensed operators who can give devices commands to change their frequency or cease operation.

Finally, Cisco recommended that the commission look at the 802.11k Radio Resource Measurement standard  that allows access points or WLAN switches to provide site reports to clients to let them know if there’s too much interference on a certain channel to be used for WLAN devices.

Mary Brown, the director of technology and spectrum policy at Cisco Government Affairs, emphasizes that Cisco isn’t specifically recommending either the 802.11y standard or the 802.11k standard, but is simply asking the commission to look at all the options before making a final decision. She says Cisco wants the FCC to act promptly, but she also adds that it would have no problem if the commission delayed its decision until November “to make sure they take time to make right technical decision.”

The concerns raised by Cisco in its FCC filing are similar to the concerns raised by broadcasters who are worried that WLAN devices operating on white spaces could degrade television broadcasting quality. However, unlike broadcasters who want to stop the use of all unlicensed wireless devices in white spaces, Cisco signaled that it supported the efforts of companies to craft WLAN technology for use in white spaces “provided that the devices do not cause harmful interference to current users of that spectrum.”