Dynamic Spectrum Sharing: the TV whitespaces and beyond
Anant Sahai, Kristen Ann Woyach and Kate Harrison
National Science Foundation
The radio spectrum is undergoing a revolution, and it is about time! The current regulatory regime was essentially established back in the 1920's --- before Shannon's information theory revolution that introduced the idea of bits and the fact that they represent a universal common currency for communication, before the transistor and VLSI revolutions made it possible to implement radios unimaginable in the days before them, before universal computers and programmability were anything other than a twinkle in the eyes of logicians, before Moore's Law told us that exponential-scale change is not a one-off-event but a steady march, and before the advent of the worldwide Internet and global cellular telephony! This old approach is based on the idea of static frequency allocations, dedicated to one kind of application, and then further assigned to one user in a given geographical area --- on the timescale of years to decades. We are working to figure out what the new approach to wireless spectrum should be, one that embraces the technical possibilities of frequency agile radios, but takes seriously the modern "ecosystem" as well as the need for trust, evolvability, etc....
Figure 1: The current static way of doing frequency allocations.
Figure 2: Estimate for TV whitespace channels available.