My teaching and research are in the area of communications and networking. Together with my collaborators we investigate various aspects of communication network design and analysis including architectures, protocols and mathematical models for wireless communications, mobile ad-hoc networks, sensor systems and satellite communications as well as service provisioning in the internet. In wireless access networks we proposed cellular architectures, power control and channel allocation schemes for efficient spectrum usage and quality of service provisioning as well as new methods for mobility tracking. Our work in wireless ad-hoc networks focused on capacity issues, time-varying topologies and maximum throughput algorithms; furthermore we proposed protocols for topology control and service discovery as well as for providing quality guarantees to multi-class traffic; finally we investigated cross-layer design approaches in broadband wireless as well as the effective use of s mart antennas and its interaction with the physical and the access layer. In the context of sensor networks we considered the issue of energy efficiency and we proposed the notion of lifetime maximization together with network control algorithms for achieving it. We developed mathematical models for quantifying quality of service in the INTERNET and proposed schemes and architectures to achieve it including, switch scheduling schemes, end-to-end congestion control , multicasting , as well as novel information distribution schemes for content delivery. More detailed information about the research activity is provided in the section research activity by area.
