FCC Promotes Wireless Backhaul by Relaxing Microwave Rules

Yesterday, the FCC released an Order and Further Notice of Proposed Rulemaking relaxing its rules to facilitate the use of microwave spectrum, particularly in the 7 GHz and 13 GHz bands (6875-7125 MHz and 12700-13150 MHz, respectively), for wireless backhaul.  The FCC’s action opened up 650 MHz of spectrum in rural areas where TV pickup operations are not already licensed. This decision implements a National Broadband Plan recommendation that the FCC “enhance the flexibility and speed with which companies can obtain access to spectrum for use as wireless backhaul and other wireless services” to promote broadband deployment, including 4G in rural America. The FCC adopted many of its earlier proposals, which we summarized here last year. Significantly, the new rules will not disturb existing CARS microwave licenses operating in the 13 GHz band. 

“Wireless backhaul” is use of spectrum instead of fiber, copper, or cable to transport data traffic over longer distances, typically from a wireless provider’s cell sites back to a wireline backbone network. The use of wireless backhaul will facilitate wireless broadband deployments by lowering costs and providing a practical alternative where fiber and other wired technologies are unavailable, particularly in rural areas.  

Briefly, the rule changes are as follows: 

·         The FCC will issue new fixed microwave service licenses under Part 101 in rural areas in the 7 GHz and 13 GHz bands.  Those bands have historically been exclusively available for the Broadcast Auxiliary Service (BAS) and Cable TV Relay Service (CARS). Traditionally, only MVPDs and broadcasters were licensed in these frequencies for both fixed and mobile video traffic transport. Under the new rules, the FCC will license new entrants only in the more rural areas where no mobile CARS or mobile BAS (or “TV Pickup”) stations are currently licensed. The FCC kept this limitation in order to protect mobile CARS and BAS electric newsgathering (ENG) operations, which send signals of live news reports back to broadcast studios or cable headends. The FCC found that any broader general use of these bands in urban areas would risk too much interference with ENG transmissions. In addition, to preserve future ENG operations in rural areas, the FCC also reserved 50 MHz in each of the two bands for exclusive rural mobile CARS and mobile BAS use.  

·         The FCC eliminated the “final link” rule, which prohibited broadcasters from using non-BAS frequencies for their last mile video backhaul links to studios. The FCC adopted this change despite some concern that it would reduce the amount of wireless spectrum available in urban areas for telecommunications backhaul links.

·         The new rules allow for adaptive modulation in microwave operations, which will enable temporary divergences from the FCC-mandated minimum carriage payloads. Traditionally, the Commission required a certain amount of traffic to travel over microwave links in order to ensure efficient use of the spectrum. This new operating flexibility, the FCC reasons, will increase both the long-term reliability and cost-effectiveness of middle-mile links.  

·         Finally, the FCC declined to adopt its proposal to allow licensees to add “auxiliary stations” to existing point-to-point microwave licenses. Under this proposal, microwave licensees would have been able to add multiple new antenna sites to an existing license in order to re-use authorized frequencies in a way that varies from the underlying license parameters. Instead, the current rules will remain in place, which require microwave spectrum licensing on a site-by-site basis for each path, frequency, and antenna deployed.  The FCC determined the proposal would have caused too much interference to existing licensed microwave operations.  

The FCC also asked for comments on certain proposed additional rule changes. Among those proposals are:   

·         Allowing smaller antennas in the 6 GHz, 18 GHz, and 23 GHz microwave bands. In comments submitted on last year’s NPRM, many parties pointed out that carriers could deploy smaller antennas more cheaply because they put less weight and load on towers. Other commenting parties opposed the idea, noting that smaller antennas often use spectrum less efficiently by necessity of their size, so their deployment could lead to more harmful microwave band interference.   

·         Whether to further relax the minimum payload standards for microwave operations in rural areas. As with the adaptive modulation rule change discussed above, exempting licensees in non-congested areas from minimal capacity requirements could lead to cost savings in wireless backhaul. Critics charge that further reductions in efficiency standards (even if limited to rural areas) would simply encourage more inefficient spectrum use while simultaneously discouraging technical innovation.  

·         Authorization of wider channels in certain microwave band. Currently, microwave licensees in the lower 6 GHz and 11 GHz bands are limited to 30 and 40 MHz authorized channels. Commenters argue these bands could easily accommodate new licensed operations using 60 and 80 MHz channels. The FCC asks whether increases in authorized channel size are appropriate in light of increased backhaul traffic demands, or whether such large allocations would merely encourage inefficient use and needlessly deplete this spectrum.  

Comments and reply comments on the NPRM are due October 4 and October 25, 2011.