Wireless Network Design: Optimization Models and Solution ...

2 Introduction to Wireless Communications 11
developed for wired networks, in the wireless domain results in severe throughput
degradation due to the time varying nature of the wireless channel [4].
Most systems however, use the simplified Internet layering scheme which was
proposed in a Request for Comments (RC) document of the Internet Engineering
Task Force (IETF) [11]. This scheme broadly consists of 4 layers: link layer, Internet
layer, transport layer, and application layer [11]. Note that several variations of these
layering methods exist and different authors interpret the RFCs in a slightly different
manner [42].
Next, we look at the main elements of a digital communication system.
2.1.2 Digital Communication System
The basic functional blocks in a digital communication system are shown in Figure
2.2. The digital signal to be transmitted is first processed through a source encoder
[37]. Most common digital data files have a significant amount of redundancy.
Fig. 2.1 Layered architecture