Design of Fair Scheduling Mechanisms with QoS Consideration for IEEE 802.11e Wireless LANs

• Main Authors: Han-Yi Liao, 廖漢雨
• Other Authors: Huei-Wen Ferng
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/20338374694329459829

碩士 === 國立臺灣科技大學 === 資訊工程系 === 95 === With the rapid development of wireless LAN technologies and the popularization of various kinds of mobile devices, multimedia applications in wired networks are also expected in wireless networks. In the IEEE 802.11e wireless LAN, different priorities are given to multimedia transmissions depending on the quality of service requirements. Because prioritized transmission results in the starvation problem for low-priority services or flows, how to simultaneously achieve fairness and quality of service in such an environment is an important issue. Therefore, four fair scheduling schemes, i.e., enhanced distributed deficit round robin with backoff interval (EDDRR-BI), enhanced distributed elastic round robin with backoff interval (EDERR-BI), enhanced distributed deficit round robin (EDDRR), and enhanced distributed elastic round robin (EDERR) are proposed and studied in this thesis. EDDRR-BI and EDDRR use deficit counters for fair scheduling, while dynamic values of allowance are utilized for EDERR-BI and EDERR to take care of fairness. Through a simulation approach, EDDRR-BI and EDERR--BI are compared with enhanced distributed channel access (EDCA) of IEEE 802.11e and a previously proposed scheme called elastic enhanced distributed coordination function (EEDCF). Based on simulation results, we show that EDDRR-BI and EDERR-BI can improve throughput, collision rate, delay, and fairness. For schemes without backoff intervals, they are also compared with EDCA and a previously proposed scheme called distributed elastic round robin (DERR). Again, we demonstrate that the two proposed schemes have better performance and fairness. Our results also show that schemes without backoff intervals perform even better than schemes utilizing backoff intervals.