Liu, Lingjia (2008-05). On delay-sensitive communication over wireless systems. Doctoral Dissertation.
This dissertation addresses some of the most important issues in delay-sensitive
communication over wireless systems and networks. Traditionally, the design of communication
networks adopts a layered framework where each layer serves as a "black
box" abstraction for higher layers. However, in the context of wireless networks with
delay-sensitive applications such as Voice over Internet Protocol (VoIP), on-line gaming,
and video conferencing, this layered architecture does not offer a complete picture.
For example, an information theoretic perspective on the physical layer typically ignores
the bursty nature of practical sources and often overlooks the role of delay in
service quality. The purpose of this dissertation is to take on a cross-disciplinary
approach to derive new fundamental limits on the performance, in terms of capacity
and delay, of wireless systems and to apply these limits to the design of practical
wireless systems that support delay-sensitive applications. To realize this goal, we
consider a number of objectives.
1. Develop an integrated methodology for the analysis of wireless systems that
support delay-sensitive applications based, in part, on large deviation theory.
2. Use this methodology to identify fundamental performance limits and to design
systems which allocate resources efficiently under stringent service requirements.
3. Analyze the performance of wireless communication networks that takes advantage of novel paradigms such as user cooperation, and multi-antenna systems.
Based on the proposed framework, we find that delay constraints significantly
influence how system resources should be allocated. Channel correlation has a major
impact on the performance of wireless communication systems. Sophisticated power
control based on the joint space of channel and buffer states are essential for delaysensitive