Sigfox

Laurence Sellier

Christophe Fourtet

A method of authenticating data packets transmitted by terminals and received by a station, each terminal successively transmitting data packets in a plurality of different frequency bands according to a frequency hop sequence specific to said terminal, includes, for a data packet received by the station, i) measuring the frequency band in which the considered data packet has been received, ii) extracting an identification code from said considered data packet, iii) determining a theoretical frequency hop according to the frequency hop sequence associated with said extracted identification code, and iv) calculating a frequency hop deviation according to the theoretical frequency hop and to the frequency bands measured for the considered data packet and for the previous data packet. The authentication method includes determining whether data packets have been transmitted by the terminal associated with this identification code according to at least one frequency hop deviation.

Method for authenticating data packets received by a station of a digital telecommunications system

The invention relates to a system for forming an asynchronous communication network for receiving client transmitters, comprising base stations that are remote from one another, said network enabling the geolocation of the client transmitters. For this purpose, the system comprises a plurality of stationary reference transmitters, the positions of which are known and each of which transmits a specific beacon signal in a frequency band included within the frequency band of the network. The geolocation of a client transmitter is carried out by multilateration by taking pairs of base stations into consideration, each pair consisting of base stations capable of receiving the signals from the client transmitter and the signals from a single reference transmitter, and by calculating the difference between the times the signal from the client transmitter arrived at the base stations, said difference being determined by calculating, for each base station, the difference between the times of arrival of the signal transmitted by the client transmitter and of that transmitted by the reference transmitter.

Method for synchronizing time measurements carried out in a radio communication network for geolocation purposes

A method for transmitting data via a terminal to a station of a digital telecommunications system. A first stream of data is encoded in data packets and a second stream of data is encoded in a frequency-hopping pattern. The data packets, in which the first stream of data is encoded, is consecutively transmitted in respective frequency bands of a frequency resource. The frequency bands are determined based on the frequency-hopping pattern in which the second stream of data is encoded.

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Toulouse, France

Laurence Sellier