Design of a PSK modulation/demodulation method free from interruptions

This paper discusses a PSK modulation/demodulation method free from interruptions providing continuous telecommunication services. The feature of the system is that the transmission rate or the carrier frequency is switchable without interruptions during communications. Functions of the system are outlined. The design procedure and design results are presented. Another feature of the proposed method is its transmission format. In the normal operation, a control information is inserted into the transmission format and a preamble is inserted only when the transmission rate or the carrier frequency is to be changed. By this elaboration, interruptions can be avoided. As a detailed example of the design, a link configuration is assumed where the convolution encoding Viterbi decoding with coding rate of one-half is used as the forward error correction scheme, and the information rate is made variable among 2B+D, B+D, and D based on the basic ISDN service. Parameters concerning the transmission format and the modulation/demodulation are determined. The control information and protocol required in the functional switching needed in avoiding interruptions are also discussed. By this method, limited radio frequency resources can efficiently be utilized, appropriately varying the transmission rate according to traffic or switching the carrier frequency.