Revise Wireless Backhaul Rules

Recommendation #38

FCC Chapter: 5.10

Status: Completed

The Federal Communications Commission should revise its rules to allow for greater flexibility and cost-effectiveness in deploying wireless backhaul.

The FCC should commence a proceeding to update Part 101 microwave rules -- which are intended to enable a
high level of service reliability, but may also limit deployment flexibility in coverage- or capacity-limited situations -- to reduce the cost of backhaul in capacity-limited urban areas and range-limited rural areas.

In particular, the proceeding should revise rules consistent with the following:

• Greater spatial reuse of microwave frequencies, particularly in urban areas. Public comment has raised the possibility that rule changes could enable more efficient use of spectrum, particularly in the area immediately surrounding a microwave station. Such changes, it is claimed, could dramatically increase the ability to use spectrum for backhaul in high-congestion areas, especially urban areas. The FCC, in the context of a larger Part 101 proceeding, should expeditiously consider whether the proposal merits changes to the existing rules.
• Modification of minimum throughput rules, particularly in rural areas. The FCC should consider modifying rules on minimum data throughput for each authorized microwave channel when the benefits are clear. Several parties have noted the potential benefits of using adaptive modulation in rural areas to expand the range of backhaul systems. Adaptive modulation is a technique whereby the data rate is dynamically adjusted based on channel conditions at any moment in time. All of these changes could potentially reduce operational costs, particularly in rural areas where microwave backhaul is essential to providing broadband service.
• Restrictions on antenna size. The tower lease costs for mounting antennas can constitute up to 40% of the total cost of microwave ownership. These lease costs are directly related to the size of the antenna. Smaller antennas may also "cost less to manufacture and distribute, are less expensive to install because they weigh less and need less structural support, and cost less to maintain because they are less subject to wind load and other destructive forces." Current rules on antenna sizes are designed to maximize the use of microwave spectrum while avoiding interference between operators. It is important to ensure these standards are up-to-date in order to maximize the cost-effectiveness of microwave services.
• Use of higher frequencies. Technology has historically been the most important factor limiting the use of higher frequencies. Every successive decade has seen that limit pushed higher. This does not mean that differences in propagation factors at higher frequencies can be ignored. Systems using higher frequencies will need to adopt new architectures and technologies, appropriate to the frequency and the application, as has every past innovative radio application. It must be emphasized that the use of higher frequencies is "compatible and synergistic" with the new wireless paradigms, rather than the new paradigms evolving as forced responses to the necessity of using higher frequencies. Simultaneously, it is important to be mindful of the implications for network engineering of systems operating at higher frequencies, and the impact of those implications on the economic viability of those systems. This Part 101 proceeding should commence in 2010.