A delay-based ACK scheme for VoIP services in an IEEE 802.11e infrastructure network

In recent years, voice over Internet Protocol (VoIP) has gained much attention in wireless local area networks (WLANs). Although IEEE 802.11e has been standardized to provide voice traffic with quality of service (QoS) support, the voice quality will still be severely degraded with a large amount of best-effort traffic generated by distributed coordination function (DCF) or enhanced distributed channel access (EDCA) stations. In this paper, we propose a novel ACK mechanism called delay-based ACK (DB-ACK) scheme to protect voice traffic from legacy DCF users and AC_BE traffic by using adaptive DIFS and AIFS values at DCF and EDCA stations respectively in an 802.11e infrastructure network. We evaluate the performance of the DB-ACK scheme through extensive simulations. Simulation results show that the proposed scheme can well support the stringent QoS requirements for voice traffic while maintaining acceptable throughput for best-effort traffic.