Dynamic Transmit Power Control in Multi-interface Multi-hop Wireless Mesh Networks

• Main Authors: Shih, Chung-Boa, 施宗葆
• Other Authors: Lin, Ting-Yo
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/42455677634712720425

碩士 === 國立交通大學 === 電信工程研究所 === 105 === In modern wireless network environments, computing devices are typically portable, light-weight, and have limited battery power . When a wireless communication module transmits signal, it usually applies maximum transmit power which might waste energy. We observe that max transmission power is unnecessary for most successful communications. In addition, using lower transmit power can potentially reduce the interference to neighboring nodes. Motivated by this, we propose a transmission power control algorithm in this thesis. It not only saves energy to extend the lifetime of wireless nodes, but also reduces the interference and encourages more concurrent transmissions. We measure and analyze the relationship between the varying transmit power and link quality from an operational testbed. We investigate the relationship between Packet Delivery Ratio(PDR) and Received Signal Strength (RSS) by keeping track of the Received Signal Strength Threshold (RRSThreshold). Each transmitter dynamically adjusts the transmit power according to the current RSS information and RSSThreshold. For performance evaluation, we build a prototype to validate our algorithm. Raspberry Pi 2 Model B and Wi-Fi module (TP-Link TL-WN722N) are used in the prototype. We conduct the experiments with different node distances, additional interfering nodes, concurrent transmissions and multi-channel multi-hop scenarios. We also compare our algorithm with default mechanism (maximum transmit power). From the experimental results, our algorithm has the ability to dynamically adjust the transmit power, maintain high PDR, save energy, reduce interference and increase concurrent transmissions.