Design concept of TDMA cellular mobile radio units

A digital mobile communication system that allows more cellular subscribers as well as achieving upgraded service has been developed. The design concept and performance of car-mounted, portable, and handheld cellular telephones for the digital mobile communication system is presented. Major system parameters standardized by RCR, which are mandatory in the Japanese digital cellular system, and the mobile radio unit configuration based on the specification are introduced. Novel technologies for achieving highly precise and efficient pi /4-shifted QPSK transmission in digital mobile radio units are shown, and excellent performance is demonstrated. Furthermore, based on these technologies, a design method to achieve low power consumption and small-sized handheld telephone is shown.<>