Training, search and storage of code books are key issues for vector quantization. Research aimed at increasing the robustness of source coding systems. For a user of a communication system, channel disturbances are often the determining factor for the deficiencies of the channel. Another interesting principle involves optimizing the source coder so that channel errors have a minimal influence. Speech coding, with the aim of decreasing bit rate while preserved quality.
Different methods are of interest for different applications.
Characteristics of speech signals and hearing are employed. Models of signals as well as for perception are necessary tools. Activities also include general aspects of coding, modulation and detection. Personal communications is an important application.