Frequency jump radiocommunications system with interburst redundancy

Abstract

A radiocommunications system for transmitting packets of digitized data between a central station and a plurality of subscriber stations using a common set of frequencies. Each subscriber station and central station has an input circuit for compressing packets of digitized data, and a transmitter for generating a transmitter carrier wave. The carrier wave frequency of the transmitter is varied by steps with predetermined frequency values according to a frequency law assigned to the subscriber station and independent of the laws assigned to the other subscriber stations. The frequency steps are synchronous with the frequency steps of the other subscriber stations and the steps have the same duration. A processing circuit coupled between the input circuit and the transmitter calculates and inserts redundancy data into the succession of digitized data. A reception circuit is also provided in each subscriber station and central station with a demodulator for demodulating digitized and redundancy data received by the subscriber station; a memory circuit coupled to the output of the demodulator for storing the demodulated data; and an output circuit, coupled to the output of the memory circuit though a circuit for validating and transferring the demodulated data. A comparator controls the output circuit by comparison of the digitized data and the corresponding redundancy data.