The Institute of Electrical and Electronics Engineers-United States of America (IEEE-USA) filed a letter to both the FCC and NTIA on May 6, 2010, seeking to revive an effort that would provide a defined harmful interference metric. The standards organization states that "the intent of this letter is to offer suggestions to both agencies to improve the transparency and speed of spectrum allocation decisions. These suggestions focus on how the two agencies can develop a more transparent framework for making “harmful interference” determinations."

The letter comes on the heels of the rapidly moving spectrum inventory legislation making its way through Congress. IEEE-USA states that any spectrum inventory that seeks to reallocate spectrum must have a clear definition of harmful interference to ensure protection of incumbent users. Failing to define interference could deadlock spectrum reallocation and the IEEE-USA letter cites a few examples.

This is a complex issue. The FCC considered a similar action when it proposed an "interference temperature" metric in an attempt to introduce low power unlicensed devices into point to point microwave bands and failed in the effort. Industry could not agree on a criteria to sufficiently protect incumbents and the same result may happen if the FCC takes up IEEE's proposal. IEEE-USA makes a valid point about spectrum reallocation difficulties. UTC will track this item  and report on progress, if any. The IEEE letter is available for download here.