An ACK-based polling strategy for supporting high performance and QoS in IEEE 802.11 wireless networks

The infrastructure architecture of wireless local area networks (WLANs) has been widely established in many environments to provide convenient multimedia services. However, in this standard operation, arbitrary channel contention and frequent handshaking significantly affect data transmission efficiency between AP and stations (STAs). This paper proposes an ACK-based polling strategy (APS) to reduce the overheads of channel contention and frequent handshaking via adaptively arbitrating and scheduling the transmission sequence of STAs. That is, the proposed APS makes AP be able to defer the ACK frames replied to the STAs, which still have more data in their buffers, in order to temporarily terminate their subsequent contention accesses. A terminated STA is permitted to transmit data frame again only when it receives the ACK frame replied from AP. Using the ACK-based polling mechanism, the overheads of channel contention and frequent handshaking are reduced and the network goodput is improved. Using the ACK frames, the APS can be further enhanced to support the quality of service (QoS) for various multimedia applications. Simulation results demonstrate that the APS with enhanced QoS function is able to efficiently cope with various transmission requirements in multimedia WLANs.