Channel Allocation and Authentication Schemes for Wireless Mesh Networks

• Main Authors: Shih, Yung-Chien, 史永健
• Other Authors: Tseng, Chien-Chao
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/00940706052586723658

博士 === 國立交通大學 === 資訊科學與工程研究所 === 99 === While wireless mesh networks (WMNs) are gaining momentum in widespread application, we are concerned with fast handoff in a secure mesh environment. To this end, we present a means in the context of IEEE 802.11s by allowing a mesh portal to act as an IEEE 802.1X authenticator, to reduce costly IEEE 802.1X authentications during handoff. As the mesh portal (MPP) engages in IEEE 802.1X authentication and cryptographic key management, our scheme maintains an end-to-end secure channel between a mobile station and the MPP wherever the station roams in the network. Therefore, without compromising required robust security, IEEE 802.1X authentication can be bypassed during handoff to reduce overall delay in an approach suggested for moderately sized networks. A WMN suffers from a co-channel interference problem when mesh nodes share the same wireless access channels. Therefore, the overall throughput of WMNs may not be able to increase substantially even with broadband physical layer technologies. The problem also causes unexpected transmission delays in the network, which could seriously influence the process of authentications. As a remedy, we propose an end-to-end channel allocation scheme, extending the radio-frequency-slot method and providing stable throughput for end-to-end packet delivery in WMNs. Although separating transmissions of data and acknowledgment packets on two different channels is not our new finding, we observe that the non-overlapping channels can be efficiently reused if the concept is introduced into our scheme. Moreover, by applying link and path metrics for route selection, the end-to-end throughput and delay can be maintained, and the overall throughput of WMNs can be improved. For fast handoff, a mobile station should be able to detect immediately the changes of a network environment, such that the station can perform handoff process at correct time. To this end, we designed and implemented a middleware platform, providing application programming interfaces (APIs) for upper applications to use cross-layer signaling and event notification mechanisms. The applications can configure and acquire status of underlying protocol stack via the cross-layer signaling mechanism, and can immediately detect changes of a network environment via the event notification mechanism.