Performance Analysis of the IEEE 802.11e Enhanced Distributed Coordination Function using Cycle Time Approach

摘要

The recently ratified IEEE 802.11e standard defines the Enhanced DistributedChannel Access (EDCA) function for Quality-of-Service (QoS) provisioning in theWireless Local Area Networks (WLANs). The EDCA uses Carrier Sense MultipleAccess with Collision Avoidance (CSMA/CA) and slotted Binary ExponentialBackoff (BEB) mechanism. We present a simple mathematical analysis frameworkfor the EDCA function. Our analysis considers the fact that the distributedrandom access systems exhibit cyclic behavior where each station successfullytransmits a packet in a cycle. Our analysis shows that an AC-specific cycletime exists for the EDCA function. Validating the theoretical results viasimulations, we show that the proposed analysis accurately captures EDCAsaturation performance in terms of average throughput, medium access delay, andpacket loss ratio. The cycle time analysis is a simple and insightfulsubstitute for previously proposed more complex EDCA models.