Wireless Network Design: Optimization Models and Solution ...

2 Introduction to Wireless Communications 23
where P is the power constraint at the base station. This capacity region is illustrated
in Figure 2.9. Again, the achievable rate with FDMA is also shown in the
figure.
These theoretical capacity bounds are very useful for network designers in planning
and resource allocation issues.
2.4 Channel Coding
Channel codes, also referred to as forward error correction (FEC) codes, are used
to reduce the effective bit error rate when data is sent over a lossy medium such
as a wireless channel. There are two main categories of FEC codes - block codes
and convolutional codes. We now briefly discuss the properties of these codes. For
simplicity, we only discuss binary codes in this chapter. Codes over other alphabets
are discussed in several references such as [26, 51].
Fig. 2.8 Illustration of capacity of an uplink channel