A mobile station (106) establishes a real time communication link via
an
access point (102) for carrying voice or other time-sensitive data. A WLAN
subsystem (204) of the mobile station is normally kept in a low power state.
Upon initiating a communication link the mobile station signals to the access point
that unscheduled power save delivery mode will be used (614), and the access
point reserves resources to assure the necessary quality of service. The mobile
station initiates a frame transaction by first powering up the WLAN subsystem (712),
acquiring the WLAN channel (407), and transmitting a polling frame. Upon
successful receipt of the polling frame the access point prepares to reply with
an aggregate response. The aggregate response commences by transmitting all data
in an aggregate buffer, including both reserved and unreserved data buffers. Upon
successful receipt of the aggregate response, the mobile station places the WLAN
subsystem back into a low power state.
