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Improving fairness index between data flows in 802.11e EDCA Wireless Ad Hoc Network by adjusting the dynamic TXOP parameter


Luong Duy Hieu, Bui The Tung, Pham Thanh Giang


Vol. 20  No. 1  pp. 117-124


IEEE 802.11 protocol is the de facto standard for media access control in wireless ad hoc network. In particular, the 802.11e is an approved amendment to the IEEE 802.11 standard that defines a set of quality of service (QoS) enhancements for wireless LAN applications through modifications to the media access control (MAC) layer. The standard is considered of critical importance for delay-sensitive applications, such as Voice, Video over Wireless LAN and streaming multimedia. The 802.11e standard is based on the EDCA method (Enhanced Distributed Channel Access) to access transmission environment with different priority for each type of data flow. Based on the analysis of the parameter impact of EDCA, we evaluates the adaptability of TXOP parameter in the single and multi hop ad hoc network environments based on the criteria of fairness between multimedia flows. The article introduces a new method aiming to adjust the TXOP parameter according to dynamic mechanism that suits the priority of each data type from the existing limitations with TXOP parameter in EDCA. The simulation results show that our proposed method will help to improve the throughput and the fairness index between data flows suitable for ad hoc networks and better than the original IEEE 802.11e EDCA method. The proposed method will be evaluated and verified by Network Simulator (NS-2) software.


IEEE 802.11, IEEE 802.11e, EDCA, MAC, quality of service (QoS), queue, wireless network, throughput, throughput according to the ratio