A wireless communication system has an access point managing a first wireless local area network. To transmit the frame, the access point: obtains data to be transmitted in multicast mode; obtains data to be transmitted in unicast mode; and constructs a physical-layer header including: in a common signalling field, an identification of each channel resource intended to be used for making the frame transmission, whether this be for the data to be transmitted in unicast mode or in multicast mode; and, in each field in a series of specific signalling fields, information representing an association between a channel resource identifier used and a unique identifier of the destination concerned or group of destinations concerned. Thus each destination can determine each channel resource to listen to in order to receive the data that are addressed to it, whether this be in unicast mode or in multicast mode.