Digital communications by Bernard Sklar. A close second is Wayne Tomasi's book. Both books provide great intuition into the matter with just about the right detail.
Once you have both of those down (and have the requisite linear algebra / probability background), read the texts by Proakis and Gallager. They are very math heavy, (but also very precise and thorough) and though often recommended by university professors, definitely not a good introduction to the subject.
recommendation on the basis of grad-level studies and research on communication / signal processing.
I second this recommendation. Proakis was my undergraduate text. I read both Gallager and Sklar at grad school and would highly recommend the later over the other two.
Once you have both of those down (and have the requisite linear algebra / probability background), read the texts by Proakis and Gallager. They are very math heavy, (but also very precise and thorough) and though often recommended by university professors, definitely not a good introduction to the subject.
recommendation on the basis of grad-level studies and research on communication / signal processing.