A wireless local area network comprising an access point and a plurality of remote stations arranged to communicate using Orthogonal Frequency Division Multiplex (OFDM). The system can operate in a first access mode wherein access to the access point is in accordance with a Carrier Sense Multiple Access (CSMA) scheme and in a temporary second access mode wherein access to the access point is in accordance with a Time Division Multiple Access (TDMA) scheme. A resource allocation of resource blocks when in the TDMA mode is furthermore such that resource blocks may be allocated to a plurality of remote stations which have overlapping time intervals and disjoint sets of OFDM subcarriers thereby allowing simultaneous communication for the plurality of remote stations within the overlapping time interval. The access operation is controlled by a single message transmitted from the access point. The invention may in particular be suitable for IEEE 802.11 systems.