...provides straightforward explanations of the hardware & software used in GSM, and also information on other analog & digital technologies that compete with GSM, like TDMA and CDMA.
The GSM network is amazing by itself. Although the new air interfaces now use more spectrum-efficient codification schemes, the overall network is just about the same. Concepts as reuse factor, soft handover, hard handover, Home Location Register, MS, and so on still apply. If you know GSM well, getting familiar with a new air interface proposal is just a matter of seeing how it implements the old GSM solution: The network architecture is the same. By the way, the part of long-term and short-term prediction for the human voice, just like the noise simulation, is incredible (I won't spoil :p ).