A WLAN
system adapted to apply QoS differentiation to a media
stream to be transmitted from a transmitting
station (STA) to a receiving STA of that
system. The transmitting STA processes the media
stream to generate a base sub-
stream and one or more enhancement sub-streams for subsequent transmission over a
wireless communication channel and assigns different priorities to different sub-streams. Depending on the channel conditions, the transmitting STA may select to discard, without transmission, portions of data from enhancement sub-streams. The selection process is based on the assigned priority and operates to preserve as much of relatively high-priority data as possible. The receiving STA then processes the received data to generate a reconstructed media stream, which provides
signal quality equal to or better than the
signal quality supported by the base sub-stream. Advantageously, a WLAN
system of the invention is adapted to change
signal quality dynamically and incrementally in a manner commensurate with
current channel conditions without the need for communication between the higher and lower network
layers. In addition, it provides gradual and graceful degradation of
signal quality when channel conditions deteriorate as opposed to abrupt degradation inherent in analogous prior art systems.