TAC TO DEVISE MODEL FOR COSTS OF SPECTRAL INTERFERENCE

Office of Engineering & Technology Chief Edmond Thomas said FCC would welcome the model, if TAC can agree. “To the extent that there can be some legitimate correlation [drawn] between cost and interference, that’s a good thing,” Thomas said. “There is no question that in certain parts of the band a little interference could be very, very harmful. In other parts of the band a lot of interference can have no harm.”

Thomas told us developing a realistic model could prove challenging for TAC. “The real question is can you come up with something that’s predictive of reality, that can be used to understand the consequences of technical decisions,” he said. “The first thing this group is going to have to do is decide if the task is even doable… It’s multidimensional and it’s extremely difficult.”

Charles Jackson, an adjunct professor at George Washington U. and former Hill and FCC staffer, presented a preliminary model he developed over the last several months, which TAC is to use as a starting point. Jackson said his model shows, for example, that widespread deployment of ultra-wideband would substantially reduce the value of spectrum in the 3-10 GHz band for future use in personal communications. The model would assess in dollar figures the extent of similar degradation.

Jackson noted that newer systems like CDMA are much more subject to degradation from low interference levels than old technologies like long-haul analog microwave systems. “When I was in the government I was skeptical of claims, which I heard more than once, that small amounts of interference initiate large economic harm,” he said: “My skepticism was more matched to the radio systems of the ‘70s than today.”

Jackson told us the formula he devised already provides an accurate estimate of the costs of widespread interference, though he’s open to making it more detailed. “Under reasonable numbers, lots of interference in a PCS band would impose costs worth billions of dollars,” he said: “We had some intense discussions here in the meeting and a lot of the people didn’t like some of the assumptions, but the actual answer is pretty robust… It’s fundamentally correct.”

Stewart Personick, a TAC member and consultant, said developing models at this stage is critical to the FCC’s ability to make some basic spectrum decisions. He said the model “appeals to me personally that -- considering how much the stakes are in whether the answers come out one way or another -- that we have this paltry amount of analysis and research on this table.” Personick said arguing that the FCC shouldn’t have an economic model for interference “is a good argument to argue that we shouldn’t have any data to make real good decisions on.”

But David Reed, adjunct prof. at the Mass. Institute of Technology, warned that an economic model could lead to erroneous numbers that unduly protect spectrum incumbents “Getting quantitative models on the table for discussion is a lot better than hand-waving,” he said. “The concern I have is the connection with economics… It’s important to recognize that in the economic calculus you have to recognize that the new system that’s coming in may in fact replace the old system.”

Reed added that assessing UWB’s economic impact can be an “unreasonable extrapolation” to draw: “In fact we may have a UWB-based telephone system, for example, or UWB-based data distribution system that in the long run is enormously more effective, less interference prone.”

Robert Lucky, TAC chmn., said the model may demonstrate “a little interference could cost a lot… The question is, would new technologies negate that qualitative conclusion?”