Barriers to Entry: The Fight Against Power- Line Communications
And for a reasonable regulatory policy for new broadband technology.
The Federal Communications Commission (FCC) and some state regulators support, for good reasons, the widespread deployment of broadband over power line (BPL) communications platforms that make use of existing electric utility distribution systems. In rural areas that have no broadband wire access, BPL could fill the gap in service. In geographic markets or sub-markets equipped only for digital subscriber line (DSL) or cable-modem service, a BPL platform would eliminate a broadband wire monopoly. Where both DSL and cable modem are available, BPL would stimulate more effective competition, just as the addition of more carriers did to the former duopoly in the commercial mobile radio services market. 1 Moreover, BPL could leverage more value from existing electric utility assets while opening opportunities to improve the quality and efficiency of electric power service through automated meter reading, distribution system management and monitoring, and remote load control and fault detection.
To achieve these benefits, policy-makers must resolve a number of issues, including: (1) harmful radio interference; (2) access; and (3) cross-subsidies.
If their policies impose diseconomies on the operation, design, or financial structure of BPL, widespread deployment of the technology is unlikely.
Harmful Radio Interference
While BPL systems do not use radio spectrum and therefore need no license from the FCC, they require devices ( e.g., couplers and repeaters) that attach to electric power distribution lines and unintentionally radiate radio frequency (RF) energy, which may interfere with amateur (HAM) radio and some government frequencies. Because of the potential for harmful interference, BPL systems are subject to the FCC's Part 15 regulations, which prescribe limits on unintentionally radiated emissions. The FCC proposed to apply those limits to BPL systems, and to require mitigation in response to valid complaints of harmful interference with the use of licensed radio frequency bands. Permanent or temporary radio frequency "notching" can be used to ameliorate harmful interference with a nearby affected radio signal. 2 Manufacturers and putative operators of BPL systems generally agreed to this proposed policy.
But representatives of licensed users of potentially affected radio frequencies urged the FCC to adopt a more restrictive policy. HAM operators argued for lower emission limits. To protect its federal government radio receivers, the National Telecommunications and Information Administration (NTIA) recommended mitigation before activation of commercial BPL systems, including frequency coordination, mandatory BPL power limitation controls, no operation in certain frequency bands, and exclusion zones. The FCC has adopted some of NTIA's recommendations, but only with certain modifications that make them less restrictive. 3
The NTIA initially claimed that peak emissions could occur at at any point along the power distribution lines. 4 Results from a variety of BPL system field demonstrations submitted to the FCC show, however, that downward radiating peak emissions occur close to BPL devices and that such emissions steadily decay as distance from the