Wireless Communication course material
Starting with a U.C. Berkeley course on wireless communication in the early 90s, I collected material on radio communication principles and systems. It has been published as a multi-media CD-ROM by Kluwer and later by Springer, but is now also available on the Internet. Although admittedly some of the material on wireless systems is a bit outdated, the physics of propagation and multipath channels, as well as the basics of multiple access schemes remain highly relevant.