Vice President, Executive Branch Advocacy 1120 20th Street NW
Federal Government Affairs Washington, D.C. 20036
EMAIL cwilner@att.com
February 10, 2004
Ms. Kathy Smith
Chief Counsel
Office of the Chief Counsel
National Telecommunications and
Information Administration
U.S. Department of Commerce
Room 4713
1401 Constitution Avenue, N.W.
Washington, DC 20230
Re: Rural Wireless Broadband Access in the 3650-3700 MHz Band, Docket No. 040116021-4021-01D
Dear Ms. Smith:
In response to the Federal Register notice published January 28, 2004, AT&T Corp. (“AT&T”) submits these comments in the above-entitled Notice of Inquiry. AT&T supports efforts to develop alternative means of accessing customers – for both narrowband and broadband services – and supports the proposed opening of spectrum for use by unlicensed devices, provided that means are established to prevent harmful interference to AT&T’s C-band satellite earth stations.
As noted in AT&T’s comments to the Federal Communications Commission, filed April 17, 2003 in ET Docket No. 02-380, AT&T operates satellite earth stations, some of which are licensed to operate in the Extended-C band (i.e., 3650-3700 MHz). Unless appropriate measures are employed, operation of unlicensed devices in the Extended-C band could directly interfere with these earth stations, which are very sensitive to interference. Nevertheless, because these earth stations generally are located in remote locations, AT&T believes that mitigation measures, such as geographic limitations, power limitations, frequency hopping, and/or use of “smart” devices, can be implemented to permit deployment of unlicensed devices in this spectrum, while still protecting these earth stations from harmful interference.
AT&T also operates other C-band earth stations that could be adversely affected by unlicensed devices in the Extended-C spectrum unless mitigation measures are implemented. Although these earth stations are not licensed to receive signals in the Extended-C spectrum band, they are authorized to receive signals in the adjacent C-band (3.7 to 4.2 GHz). Moreover, their antennae actually receive and amplify signals in both the Extended-C and C bands, although only the licensed C-band signals are processed. If interfering uses are permitted in the adjacent Extended-C band, the interference potentially could “overdrive” the earth stations’ low noise amplifiers into their nonlinear operating range and degrade C-band signals, thereby disrupting communications received at these earth stations – and those of other C-band earth station operators. AT&T nevertheless believes the interference caused by unlicensed devices could be effectively mitigated through geographic limitations, power limitations, frequency hopping, and/or use of “smart” devices.
In short, AT&T supports the proposed opening of spectrum for use by unlicensed devices, provided that means are established to prevent harmful interference to AT&T’s C-band satellite earth stations. AT&T looks forward to reviewing interference mitigation measures proposed by those seeking to use such spectrum.
Sincerely,
Carol Wilner