DELAY DEPENDENT ACCESS METHODFOR IEEE 802.11E

• Main Authors: Yu-hong Lin, 林昱宏
• Other Authors: Chien-hua Chen
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/82842618967100467805

碩士 === 大同大學 === 通訊工程研究所 === 93 === With the growing popularity and acceptance of IEEE 802.11 wireless LAN, it is essential to focus on QoS enhancement at the MAC layer of the IEEE 802.11 standard. The EDCF, proposed by the IEEE 802.11e, is a contention-based MAC protocol supporting service differentiation through different interframe spaces, contention window limits, and persistence factors for different traffic priority classes. A retransmission scheme, called Delay Dependent Backoff (DDB), has been proposed to increase the throughput of real-time packets by adjusting the persistence factors (PF) dynamically based on the delay of the real-time packets in the transmission queues and the lifetimes of the real-time packets. We modify this scheme by changing the PF range and its lower bound. Simulation results indicate that using the modified DDB in EDCF is efficient to achieve higher throughput for real-time traffic.