AN ADAPTIVE ADMISSION CONTROL FOR FRAME BASED MULTIMEDIA TRAFFIC IN IEEE 802.11 WLANS

摘要

A distributed admission control method in an IEEE 802.11 wireless LAN is provided to allocate TXOP(Transmission Opportunity) to its minimum level to enhance the QoS(Quality of Service) of a multimedia data, and enhance utilization of a radio network through scheduling and TXOP sharing. When an HC(Hybrid Coordinator) receives a TXOP allocation request message from a QSTA, it analyzes a TSPEC from the TXOP allocation request message to extract the overall size of a flow included in the message and GOP(Group of Picture) information of the flow(S4) and generate a frame schedule with respect to the flow(S6). The HC allocates a TXOP period of each frame with respect to the flow(S8). The HC transmits a TXOP allocation response message to the QSTA, and when a POLL frame is transmitted from the HC, the QSTA transmits an I frame to the HC(S10). The HC checks whether there is an idle TXOP period(S12). If there is an idle TXOP period, the HC checks whether the size of a frame to be transmitted next is larger than the TXOP period of each frame(S14). If the size of the frame to be transmitted next is larger than the TXOP period of each frame, the HC adds an additional TXOP period corresponding to the idle TXOP period to a TXOP period of the next frame and allocates the TXOP period to the frame to be transmitted next(S16,S18).