France Telecom

Mohamed Ghozzi

Michael Dohler

Michaël Dohler

The invention relates to a method of determining the presence of a telecommunications signal on a frequency band, said signal being assumed cyclostationary, comprising steps of:

Method of determining the presence of a telecommunications signal on a frequency band

An unoccupied frequency band (W) is detected in a telecommunications network by obtaining first values relating to a signal received (r(n)) for respective corresponding times, in this frequency band. Next, a compound signal is obtained in the form of vectors (Y) respectively associated with these first values, each vector having M components resulting respectively from the products of the first value associated with said vector and M second values relating to the signal received respectively for M offset times (ti) shifted with respect to the time corresponding to said first value, M being a greater integer. Next, at least one first and one second energy vector (E, E) are determined, each containing M components corresponding respectively to energy values of the compound signal for the M offset times, respectively on a first frequency band and on a second frequency band, which are situated either side of a reference frequency. Finally, a decision is made as to whether said frequency band is unoccupied on the basis of a comparison of a distribution of the energy values of the compound signal over the first frequency band and of a distribution of the energy values of the compound signal over the second frequency band.

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Marseille, France

Mohamed Ghozzi