The RF spectrum: is all the beachfront property gone?

Summary form only given, as follows. This talk examines the challenges in spectrum sharing and spectrum allocation and challenges the audience to think in new ways about multiple access technologies. Historically, we have only used code, time, frequency, space, and power to separate systems sharing a band, and rarely more than two of these at once. In the future, as wireless system developers wrestle with cost of allocated spectrum versus the interference challenges of unlicensed or shared spectrum, we may need new ways to maximize the utilization of our precious electromagnetic ¿real estate.¿