Interference-Resisted and Soft Guaranteed QoS for Heavy Contention 802.11 Networks

• Main Authors: Yu-Hsiang Lei, 雷喻翔
• Other Authors: Hung-Yu Wei
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/59837195795995913078

碩士 === 國立臺灣大學 === 電機工程學研究所 === 96 === Nowadays, IEEE 802.11 based wireless devices are widely deployed. The new 802.11p standard is an amendment of legacy 802.11 to provide wireless access in vehicular networking environment. In this work, we propose an 802.11p compatible mechanism to ensure guaranteed QoS for the vehicular applications. Vehicular wireless devices move within their transmission range during a limited timeframe. Traffic alerting messages and protocol signaling messages require guarantee QoS transmission within the limited time duration. To transmit high priority data packets during these time-constraint transmission opportunities, MAC level support is essential for opportunistic networking design in vehicular wireless networks. In addition, current 802.11e QoS mechanism only provides differentiated QoS but not guaranteed QoS. Under such contention-based 802.11 environment, there are strong needs to provide assured delivery mechanism for opportunistic access. Since hard guaranteed QoS in wireless random access networks is unlikely achievable, we proposed a soft guaranteed QoS mechanism for 802.11 based systems. To understand the benefit of our design, we use Markov chain model to evaluate this system. We also use NS-2 simulations to validate the performance model. The performance results show that the proposed scheme has better performance both on throughput and successful transmission probability within a given time period.