Canon Kabushiki Kaisha

Canon Research Centre France S.a.

Francedillaois Delumeau

Philippe Piret

The present invention relates notably to a method for sharing a transmission medium between communication apparatuses having an identifier, each adapted on the one hand to transmit messages by device of the transmission medium, during so-called 'transmission' phases, and/or on the other hand to receive messages by device of the transmission medium, during so-called 'reception' phases. Each communication apparatus stores, in each reception phase, and associated with identifiers, activity states representing the last messages transmitted by the communication apparatuses having these identifiers, in their own transmission phases. In a so-called 'transmission preparation' phase preceding each transmission phase, each communication apparatus determines, according to first predetermined rules taking into account at least certain of the said activity states, at what moment it can transmit a message on the transmission medium.

Method, means and system for communicating on a shared transmission

The present invention proposes a method and a device for detecting, amongst a set of signals, the presence of a periodic signal of period of occurrence T, in which a signal discriminating the said signal in the said set of signals is delivered. According to the invention, the discrimination signal is sampled in ln samples over more than one period T, a state value B(i) representing its level, and a true correlation value SR is calculated, by cumulating, for pairs of samples i and i+Z, the instantaneous value of correlation between the state value B(i) and the state value B(i+Z), the samples i and i+Z being located at instants shifted by a period T. Then, for said pairs od samples, the rate r of samples having the said signal over the total number of samples is measured, at least one so-called 'theoretical correlation average' value is determined, and the true correlation value SR is compared with each theoretical correlation average value and from this the presence or absence of the signal to be detected is deduced.

Growing community of inventors

Rennes, France

Francedillaois Delumeau