I spent a few hours following this issue because I think it is important for the future of the wireless and broader ICT industry.
The problem stems from allocation of broad bands of spectrum for use by GPS. This was done largely out of necessity because GPS requires the use of satellites to specialized, handheld and embedded device receivers, resulting in very low signal levels. Wide band technology that pushes suppliers and applications to use as wide of spectrum as they think is possible. The conflict arises due both the nature of the wide band technology and the lack of enforcement or commercial motivation to restrict sensitivity outside of the allocated GPS bands.
This can be seen in the initial and subsequent test results after LightSquared modified their network plans. Also, the GPS industry imposed what appears to the non-GPS expert like myself to be a very low threshold for non-interference - when I read the initial report it immediately struck me as exceptional requirements. Several points snap out of these reports including that many devices in use today are not subject to interference because they took precaution in their designs. Relatively simple measures including use of selective antennas and band pass filters have been shown in test results submitted by equipment suppliers, mobile network operators, as well as LightSquared and suppliers aligned with them, to resolve the problems of interference.
The problem remains for equipment that has not followed the GPS, DoD and FCC guidelines for non-interference of GPS equipment. Unfortunately, this includes many critical applications such as flight navigation and precision commercial applications such as agriculture.
On the other hand, I thought that LightSquare's initial proposal was naive at best: They proposed use of some 30,000 high powered base stations while not addressing the interference issues that were due to crop up. Their stance was, rightly or wrongly, that they were entitled to use their spectrum as if GPS were designed within best practices to mitigate interference. Regardless of whether that is technically correct, it was bone headed.
Both sides have wished to steamroll the regulatory review process. That is actually the heart of the matter: in order to make more spectrum available for use by 'smart wireless technology' that is evolving to the commercial forefront today, incumbent uses must come under tighter use of 'best practices' or be reformed to use newer versions or entirely new technologies.
The GPS industry is a pariah of what is wrong with incumbent use at large: GPS takes up large swatches of spectrum using technology that is pegged by slow to change satellite networks. It is, in my opinion, arrogant and prejudiced. Regardless of what I think, it can be proven that the GPS industry has ignored advances aimed at reducing the spectrum footprint even while providing the benefit of better penetration, faster response, and more accurate position measurements. Among the many potentials for advancement of GPS are coordinated use along with terrestrial communications networks, particularly 3G and LTE networks. The way the GPS industry is disposed to operate tends to push against progress needed to advance both their own field and to also free up part of their lock on GPS and encroachment on surrounding bands of spectrum. |
