Adaptive rate control algorithm for variant bandwidth in IEEE 802.11e

• Main Authors: Chia-Wei, Chang, 張家瑋
• Other Authors: Bih-Hwang, Lee
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/82593434674122224222

碩士 === 國立臺灣科技大學 === 電機工程系 === 93 === Abstract All based on carrier sense multiple access with collision avoidance (CSMA/CA) contention base to IEEE 802.11 a/b/g wireless system at present. It is unable to offer the assurance of intact quality of service (QoS) , therefore IEEE makes 802.11e standard to offer QoS. IEEE 802.11e does different medium access control (MAC) layer to design separately to pointer coordination function (PCF) and distributed coordination function (DCF). But each nodal execution speed with bandwidth to change at any time among wireless environment, so should really carry out QoS and guarantee that there are a lot of difficulties. This thesis hopes to strengthen the assurance of QoS to the variable and bandwidth characteristic in the wireless environment. This paper proposes an adaptive rate control algorithm (ARCA) to improve throughput, collision rate and drop rate of each packet in the IEEE 802.11e EDCA mode multi-rate infrastructure wireless networks. It uses more efficient wireless LAN resources. ARCA utilizes the parameter of bandwidth factor and priority table dynamically to adjust the parameter of arbitration inter-frame space (AIFS), contention window (CW) , persistence factor (PF) of EDCA. These parameters are adjusted by ARCA to improve the efficiency of the whole system according to the rising or falling of the data rate in physical layer. Making the 802.11e high data rate of station (STA) don’t be influenced the lower data rate of STA because the channel status changed. By way of simulating, ARCA compares with 802.11e standard. It can offer better throughput than 802.11e.