I am in my 5th semester of computer science and we have a digital communication course. All the textbooks of digital comm. available in my library demand a prerequisite of Circuit analysis and Signals and systems. Is there any book which is self contained or at least less heavy on these background topics?
I highly recommend you the book Schaum's outlines of Analog and Digital Communications.
It will be the fastest refresher for the signal processing and probability concepts which are essential prerequisites for digital communications. It's not using that heavy math also, nevertheless, not a trivial one either ;-)