Advanced techniques for modulation, error correction, channel equalization, and diversity

Signal processing techniques play an important role in creating and maintaining reliable wireless digital communications. Many of these, such as low-bit-rate speech coding, convolutional channel coding with Viterbi decoding, and equalization, are already part of the first generation of digital cellular systems. Other techniques that can enhance the voice quality and system capacity include transmit and receive antenna diversity techniques, coded modulation, interference randomization and reduction, and advanced channel-decoding techniques.