Design and analysis of low-power channel access protocols for wireless ATM networks supporting multimedia traffic.

摘要

Energy efficiency is an important issue in mobile wireless networks since the battery life of mobile terminals is limited. Conservation of battery power has been addressed using many techniques such as variable speed CPUs, flash memory, disk spindowns, and so on. We believe that energy conservation should be an important factor in the design of networking protocols for mobile wireless networks. In particular, this dissertation describes the design and analysis of a low-power medium access control (MAC) protocol and the scheduling algorithm associated with this protocol for wireless and mobile ATM networks. The design of the protocol-denoted EC-MAC (energy conserving medium access control)--is driven by two major factors. The first factor is that the access protocol should be energy-efficient. The second factor is that the protocol should provide support for multiple traffic types, with appropriate quality-of-service (QoS) levels for each type. The goals of low energy consumption and QoS provision lead us to a protocol that is based on reservation and scheduling strategies. The design and analysis of EC-MAC and the comparison of energy consumption to a number of other protocols obtained from mathematical analysis are provided. These results have been validated through extensive discrete-event simulation. The core which determines the performance and guarantees the QoS lies on the scheduling algorithms associated with the MAC protocols. A priority round robin with dynamic reservation update and error compensation scheduling algorithm is used to schedule the transmission requests of the mobiles. Performance analysis with respect to different quality-of-service parameters using realistic video, audio and data traffic models is provided. By this scheduling algorithm, we show that EC-MAC, in addition to low energy consumption, can achieve high channel utilization, low packet delay, and meet the QoS requirements for multimedia traffic.;The proposed protocol and scheduling algorithm primarily deal with the traffic in a cellular area. Particularly, they schedule traffic for mobiles in the wireless last hop. The packets may be transmitted through several intermediate routes which include wireless and wired networks. Receiver synchronization of continuous media streams in the destination is required to deal with delay differences and variations resulting from delivery over packet networks. Fixed and reactive approaches have been proposed to deal with this problem. This dissertation works with an alternative predictive approach, which records historical information and uses it to make short-term predictions about network delay with the aim of not reacting too quickly to short-lived variations. The last part of the dissertation builds on previous work by exploring the use of aging techniques to improve the effectiveness of the historical information and hence the delay predictions. Three aging algorithms are proposed and compared using a simulation driven with Internet traffic traces.