A system for establishing and maintaining an "ALE" (Automatic Link Establishment) link within the context of a broadband communication, said system comprising at least: • one first master communication station designed to transmit a message to establish a communication with a desired "SLA" target service to a station called on a frequency fi, said first station comprising a first radio transceiver and a first controller and having a set of possible sub-bands for the communication; • a second called communication station on standby on a predefined frequency plan {f 1,...f M} and comprising a second radio transceiver and a second controller, said system being characterised in that: • said first master station is designed to transmit a known test sequence, Stest, on a sub-band Bk to said second called station as soon as said second called station acknowledges that it has switched to probing mode to determine the best configuration to be retained for establishing the link; • said second controller of said second called station is designed to determine quality scores on the Mk frequencies of the sub-band Bk and to transmit said quality values to said first master station; • said first master station is designed to determine, on the basis of the quality scores, the capacity of the sub-band Bk to respond to the desired "SLA" target service requested by the communication, and to select the sub-band Bk representing the required capacity or the best quality score, to determine the sub-band to be used for the communication, to confirm, to said second called communication station, the selected sub-band and the sub-channels retained and to trigger the communication with said second called station. • one first master communication station designed to transmit a message to establish a communication with a desired "SLA" target service to a station called on a frequency fi, said first station comprising a first radio transceiver and a first controller and having a set of possible sub-bands for the communication; • a second called communication station on standby on a predefined frequency plan {f 1,...f M} and comprising a second radio transceiver and a second controller, • said first master station is designed to transmit a known test sequence, Stest, on a sub-band Bk to said second called station as soon as said second called station acknowledges that it has switched to probing mode to determine the best configuration to be retained for establishing the link; • said second controller of said second called station is designed to determine quality scores on the Mk frequencies of the sub-band Bk and to transmit said quality values to said first master station; • said first master station is designed to determine, on the basis of the quality scores, the capacity of the sub-band Bk to respond to the desired "SLA" target service requested by the communication, and to select the sub-band Bk representing the required capacity or the best quality score, to determine the sub-band to be used for the communication, to confirm, to said second called communication station, the selected sub-band and the sub-channels retained and to trigger the communication with said second called station.