Patent ID: 8194604

Claim:
A wireless local area network operating using Orthogonal Frequency Division Multiplex, OFDM, the network comprising; an access point, wherein the access point operates 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 second access mode wherein access to the access point is in accordance with a Time Division Multiple Access, TDMA, scheme; and wherein the access point includes: a resource allocator for allocating resource blocks when the access point operates in the second access mode, a resource block comprising an allocated time interval and an allocated set of OFDM subcarriers; a mode controller for temporarily switching the access point from the first access mode to the second access mode of operation for a time interval in response to determining whether a number of remote stations of a plurality of remote stations attempting to access the access point in the plurality of remote stations exceeds a threshold; and a transmit unit for broadcasting at least a first message to each remote station of the plurality of remote stations indicating that the access point switches from the first access mode to the second access mode for the time interval; the first message comprising resource information specifying resource blocks allocated to the plurality of remote stations; and wherein each of the remote stations from the plurality of remote stations operates in a CSMA mode of operation the remote station is arranged to autonomously access the access point if no collision is detected and to operate in a TDMA mode of operation wherein the remote station is arranged to communicate only using resource allocated to the remote station by the resource allocator; and wherein each remote station includes: a monitor processor for monitoring for the first message, mode switch means for switching the remote station from the CSMA mode to the TDMA mode for at least the time interval in response to a detection of the first message, a resource controller for decoding the first message to identify an allocated resource block being allocated to the remote station by the resource allocator, and a communication unit for communicating with the access point using a set of allocated time intervals and a set of allocated OFDM subcarriers of the allocated resource block; wherein the resource allocator is arranged to allocate resource blocks having overlapping time intervals and disjoint sets of OFDM subcarriers to a plurality of remote stations allowing simultaneous communication for the plurality of remote stations within the overlapping time interval.