Frame acknowledgement method

In order to acknowledge uplink frames transmitted from end devices to server equipment, the server equipment allocates the end devices to groups and to subgroups. The addresses of the end devices are constructed so as to identify the groups and subgroups to which said end devices belong. The server equipment carries out mass acknowledgements by group, by broadcasting a message wherein each subgroup of said group is associated with the same item of information acknowledging, or not, said uplink frames of all the end devices of said subgroup. The mass acknowledgement further includes information representing an estimated instant of next transmission of a mass acknowledgement for said group. The server equipment acknowledges, in unicast mode, the uplink frames received that have not been acknowledged by the mass acknowledgement.