A wireless LAN (WLAN) system for communications among a plurality of users within a basic service system or cell comprising a switching access point (SAP) for transmitting and receiving point-to-multipoint communications to and from the users and a plurality of user terminals, each of which is assigned to a part available in the switching access point and defining a unique combination of a carrier frequency and a spatial beam for isolating communications among the users to prevent collisions; wherein said assignment of frequencies is not permanent and instead use is made of a dynamic or pseudo-random carrier assignment in which received request-to-send signals from the users in a shared carrier is replied to with clear to send signals from the SAP indicating the carrier that can be used for transmission.