As part of their ongoing OpenCourseWare program, MIT is offering the free online course “Principles of Digital Communication I.” Course description:
The course serves as an introduction to the theory and practice behind many of today’s communications systems.
Topics covered include: digital communications at the block diagram level, data compression, Lempel-Ziv algorithm, scalar and vector quantization, sampling and aliasing, the Nyquist criterion, PAM and QAM modulation, signal constellations, finite-energy waveform spaces, detection, and modeling and system design for wireless communication.
One important aspect of this offering is the availability of all necessary course materials free from the course website. No textbook is required, just the free lecture notes! If you wish, all course materials can be downloaded in one file, and video lectures may be viewed online anytime.
The only prerequisite is a “good undergraduate background in probability and linear systems.” Check it out.