Dealing with Interference with WiMAX

Interference—Some Assumptions

The primary objection to wireless systems is the concern that there are or will soon be too many operators on the same frequency, which will cause so much interference that the technology will become unusable. This issue is not that simple.

Such an assumption relies largely on the use of unlicensed spectrum, where, according to Larry Lessig's "tragedy of the commons" scenario, multiple operators broadcast on the same unlicensed (read "free") spectrum, ultimately rendering it useless. Although this scenario may already be evident in the case of Wi-Fi variants (largely limited to the 2.4 GHz range), WiMAX is considerably different. WiMAX currently has no problems, only solutions.

Since 1927, interference protection has always been at the core of federal regulators' spectrum mission. The Radio Act of 1927 empowered the Federal Radio Commission to address interference concerns. This act primarily focused on three parameters: location, frequency, and power. The technology of the time did not permit consideration of a fourth element: time. In the modern sense, one might consider that a spectrum used by cell phones in a metropolitan area (dense population with millions of users) would command a very high price at a spectrum auction. At the other end of the "spectrum," a frequency band, say 2.5 GHz, in an exurban or rural market may go for very little money at an auction or at resell by a spectrum broker. It is entirely possible that the wireless service provider may find a very low cost licensed spectrum and enjoy a protected spectrum, which will largely negate the concern over interference from other broadcasters (the purpose of the Radio Act of 1927 in the first place).