Architecture and algorithms for quality of service support and energy-efficient protocols for wireless/mobile networks

Wireless/mobile local area networks are becoming popular as a network connectivity alternative for a broad range of users. In order to accommodate these users, three important aspects of wireless/mobile networks have to be addressed: (i) providing quality of service (QoS)—in terms of bandwidth or delay assurances—to individual data connections, (ii) designing energy efficient protocols in order to utilize battery power efficiently, and (iii) providing security due to the nature of wireless link. The Internet community has been working on different QoS mechanisms which are mainly designed for the wired networks. It is important that these mechanisms be extended to suit the wireless domain as well. This thesis studies the adaptation of two QoS mechanisms: (i) the Integrated Services model and (ii) the Differentiated Services model. The architecture is designed to take into account the major features of wireless networks: (i) Mobility, (ii) High Losses, (iii) Low Bandwidth and (iv) Battery Power Constraints. An integrated architecture for QoS and routing is proposed because a good routing framework is essential to provide quality assurance. Two scheduling algorithms—Class Based Queueing and Deficit Round Robin—have been enhanced for energy efficiency. The scheduling mechanism uses a security enhanced energy efficient medium access (MAC) protocol. The QoS architecture has been tested on an experimental testbed using Pentium-based computers, Lucent WaveLAN wireless network cards and the FreeBSD operating system. The energy efficiency and security mechanisms has been studied using discrete event simulation due to a current lack of precise means to experimentally measure energy consumption. The results from the experiments show that: (i) the enhanced QoS mechanisms maintain service quality in presence of mobility, (ii) the routing architecture is able to route based on the QoS parameters, (iii) the scheduling architecture supports the QoS mechanism and is also energy efficient, and (iv) the underlying MAC protocol also provides security. The contributions of this thesis can be summarized as follows: An architecture for providing QoS in wireless networks is designed and implemented on an experimental testbed and the feasibility of the approach is tested and proven. The software developed as a part of this thesis are available other researchers to build upon.