In order to cover a mobile telecommunication zone, an access network node comprises a first multisector antenna to transmit and receive in several first main directions on one and the same first fixed frequency each covering a first sector having on either side of the first main direction, a common border with another first sector. A second multisector antenna situated at the same place as the first multisector antenna makes it possible to transmit and receive in several second main directions on a second fixed frequency each covering a second sector having on either side of the second main direction, a common border with another second sector, each second main direction being on the axis of a border between two first sectors. A hard handover from the first to the second frequency is triggered for a mobile which is approaching a border common to two first sectors.