US 8,045,923 B2 · Detection of unoccupied frequency band

Abstract

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 (Yn) 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 (EL, EH) 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.

Claims13

Dependent claims

A method for detecting a free frequency band (W) relating to at least one piece of communication equipment in a telecommunications network, said method comprising the following steps:

/a/ obtaining first signal values (r(n)), relating to a received signal (r(t)), for respective corresponding moments in said frequency band;
/b/ obtaining a composite signal (Y) in the form of vectors (Yn) respectively associated with said first signal values (r(n)), a composite signal vector (Yn) associated with a first signal value (r(n)) having M components (yτ1(n), yτM(n)) respectively resulting from the products of the associated first signal value (r(n)) and M second signal values (r(n−τi)) relating to the received signal for M time shifts (τi) respectively in relation to the moment corresponding to said first signal value (r(n)), M being an integer greater than or equal to 2;
and
/c/ determining at least a first and a second energy vector (EL, EH), each containing M components respectively corresponding to energy values of the composite signal for the M time shifts, respectively over a first frequency band (WL) and over a second frequency band (WH) lying on either side of a reference frequency (fref);
and
/d/ deciding whether said frequency band is free on the basis of a comparison of a distribution of energy values of the composite signal over the first frequency band relating to the M time shifts, with a distribution of energy values of the composite signal over the second frequency band relating to the M time shifts.

3 more elements

A device for detecting a free frequency band in a telecommunications network, comprising:

a processing unit (401) suitable for obtaining first signal values (r(n)) relating to a received signal (r(t)) for respective corresponding moments in said frequency band;
a generation unit (402) in order to provide a composite signal (Y) in the form of vectors (Yn) respectively associated with said first signal values (r(n)), a composite signal vector (Yn) associated with a first signal value (r(n)) having M components (yτ1(n), . . . , yτM(n)) respectively resulting from the products of the first signal value (r(n)) associated to M second signal values (r(n−τi)) relating to the received signal for M time shifts (τi) respectively in relation to the moment corresponding to said first signal value (r(n)), M being an integer greater than or equal to 2;
a unit (403) for determining an energy vector (EL, EH) comprising M components respectively corresponding to the energy values of the composite signal for the M time shifts over a determined frequency band;
and
a decision unit (320) suitable for deciding whether said frequency band is free on the basis of a comparison of a distribution of energy values of the composite signal over a first frequency band relating to the M time shifts, with a distribution of energy values of the composite signal over a second frequency band relating to the M time shifts, the two frequency bands lying on either side of a reference frequency (fref).

2 more elements

Dependencies are inferred from the claim text.

Detection of unoccupied frequency band

Life of this patent

Detection of unoccupied frequency band

Life of this patent

Abstract

Claims13