Efficient Interference Management: Regulation, Receivers, and Right Enforcement

Tags: Spectrum Policy / Technology Policy

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The management of interference between operators is at the heart of wireless regulation. To date, national regulators have borne most of this burden, attempting to manage interference by setting transmitter parameters and limiting the services that are allowed in a particular band. However, the increasing intensity of radio use is leading to more conflicts, particularly between different service allocations. The resolution of cross-allocation interference problems will have to be streamlined if the promise of wireless technology is to be realized. On October 18, 2011 the Silicon Flatirons Center convened a group of legal, economic, and engineering experts from government, industry, academia, and civil society to explore improving the management of radio interference. It is the latest step in a multi-year program on this topic organized by the Silicon Flatirons Center that began in September 2009 with a summit in Boulder on Defining InterChannel Operating Rules, and was followed by a conference in Washington, DC in November 2010 on New Approaches to Handling Wireless Interference (proceedings published in 9 J. on Telecomm. and High Tech. L. 501). The previous meetings indicated that ambiguous rights definition and ineffective adjudication contributed to difficulties in resolving cross-allocation interference conflicts, leading to delay, uncertainty, and political gamesmanship. The goal of this roundtable was to develop proposals for improved receiver management, more effective enforcement, and to seek consensus recommendations for changes in the regulatory framework that could achieve this. The role of receivers Receiver performance dramatically affects the coexistence of adjacent services. However, while transmitters are required to control out-of-band and spurious emissions to minimize interference with other services, the same does not apply to receivers. In the receiver standards approach, the regulator specifies minimum receiver performance characteristics, e.g. sensitivity and front-end performance. An alternative approach is receiver protection limits, in which the regulator specifies the in- and out-of-band interference environment that receivers can expect to operate in. 3 Consideration of case studies1 highlighted several recurring problems: (1) operators of wireless systems rely on quiet neighbors, and don’t account for changes in the radio environment; (2) operators don’t always realize that the receivers are the problem, but rather assume that a neighboring transmitter is operating outside of its band; (3) information is lost when problems are resolved on a case-by-case basis, and other operators with similar problems have no access to the resolution of an individual case. The group agreed that when considering solutions to these problems, it is important to ensure that operators, licensees, and other users have proper notice when the FCC is considering making changes to current allocations. There was consensus by the end of the discussion that protection limits are preferable to receiver standards. The group also agreed that any incremental step towards receiver management would be better than the current hands-off approach. A few participants suggested that some minimal receiver standards could be implemented as a short-term solution, but there was no consensus in this regard; there was concern that any receiver management regime, no matter how simple at the beginning, would quickly become overly complicated. Enforcement It is essential that parties can obtain efficient redress of their grievances about harm to their wireless operations, both current and foreseen. While like-to-like co-channel conflicts seem to be handled well, and are often resolved without FCC involvement, cross-allocation conflicts appear to be more time-consuming and contentious. After considering a series of cases, the participants discussed several alternatives to rule making and traditional adjudication for resolving interference disputes, including: (1) a “rocket docket”; (2) baseballstyle arbitration; (3) non-FCC solutions; and (4) using smart devices to aid in enforcement. There was no consensus on changes that might substantially improve matters.

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