A METHOD FOR A SIMPLE 802.11E HCF IMPLEMENTATION

摘要

A Hybrid Coordination Function (HCF) implementation wherein an access point'sexisting (E)DCF Enhanced Distributed Coordination Function transmit queues areaugmented by at least one strict priority HCF transmit queue. The HCF queuesare only used to schedule downlink data and CF-Poll transmissions are used foradmitted downlink flows and for uplink flows. The 802.1D user priority valueis used to select the HCF queue for an admitted flow. The strict priority HCFtransmit queues are always serviced first, in priority order before any other(E)DCF transmit queue. The channel is considered busy to (E)DCF transmitqueues while the strict priority queues are being serviced. An admissionscontrol mechanism is used to control data flows and prevents the strictpriority traffic from starving (E)DCF traffic. A single, simple AP scheduleris used for scheduling both polling times and station wakeup times. Differentembodiments of the invention includes assigning a fixed size to alltransmission opportunities, the establishment of a wakeup schedule for a power-save station, the implementation of a polling schedule for the station, theestablishment of a schedule based on a timer wheel, and the allocation of atoken bucket for a data stream with a predetermined number of tokens.