The fundamental limits of communication over a noisy channel, in particular, over an AWGN channel, are described, and channel coding is introduced as a way of approaching the ultimate information-theoretic limits of reliable communication. Linear block codes and convolutional codes are studied in some depth. Encoding and decoding algorithms, as well as basic performance analysis results, are developed. The Viterbi algorithm is introduced for both hard-decision decoding and soft-decision decoding of convolutional codes.