An Adaptive Codec and Frame Size Modification Based QoS Algorithm over Multi-rate WLANs

Abstract

The demand for Voice over IP (VoIP) services over wireless local area networks (WLANs) and Quality of Service (QoS) support in WLANs have grown substantially in recent years. IEEE 802.11e QoS enhancement standard has an important role on this expansion as well. It provides a suitable solution for delay sensitive real-time multimedia applications. Under the circumstance of any deterioration of wireless link conditions. IEEE 802.11 PHY/MAC specifications allow mobile nodes to select a proper transmission rate to optimize bit transmission. However, if a node selects lower transmission rate, packet losses and delays increase due to multi-rate effect. Therefore, all active calls have a general degradation. In this paper, we propose a fast, efficient, adaptive, proactive codec and frame size modification algorithm for the optimization of maximum throughput and voice quality on multi-rate WLANs.