Relay and Routing Selection in Relay-Based Wireless Networks

The Hong Kong University of Science and Technology
Department of Computer Science and Engineering


PhD Thesis Defence


Title: "Relay and Routing Selection in Relay-Based Wireless Networks"

By

Miss Jin Zhang


Abstract

In recent years, there has been an upsurge of interest in relay-based wireless 
networks in both industry and academia. With the introduction of relay node, 
which can forward packet for some other nodes which require relaying 
assistance, the network performance can be dramatically improved: the coverage 
of an infrastructure network is extended; spatial diversity is exploited and 
system capacity is increased; meanwhile, the transmission reliability is 
enhanced. In relay wireless networks, in order to fully exploit the benefit of 
relay transmissions, MAC and network layer schemes need to be redesigned. In 
this thesis, we will focus on the study of relay selection problem in MAC layer 
and optimal routing decision problem in network layer. Several relay and 
routing selection schemes are proposed for different wireless applications when 
concept of relaying is applied. In relay selection part, a cooperative MAC 
protocol is designed to dynamically select relay nodes according to real-time 
channel condition and contention relationship for broadcast traffics in 
vehicular networks; in respect to the cognitive radio networks, a relay-based 
cognitive radio architecture is proposed to balance the spectrum availability 
and traffic demand for secondary users, an experimental testbed is constructed 
to verify its effectiveness; we also propose an incentive relay set selection 
scheme to motivate secondary users to act as cooperative relays to forward 
packets for primary users. In routing selection part, a cooperative routing 
scheme which considers contention relationship among links is proposed in 
multi-source multi-destination multi-hop wireless networks; a cooperative 
network coding-aware routing scheme is given to enable relaying to further 
enhance the benefit of network coding in wireless networks. Finally, a 
software-defined radio-based cooperative communication testbed is built to 
evaluate the performance of various cooperative transmission schemes. The above 
studies demonstrate that with appropriate relay and routing schemes, relaying 
benefit and cooperative diversity is fully exploited and network performance is 
remarkably enhanced in relay-based wireless networks.


Date:			Tuesday, 18 August 2009

Time:			2:00pm-4:00pm

Venue:			Room 3494
 			Lifts 25-26

Chairman:		Prof. Charles Ng (CIVL)

Committee Members:	Prof. Qian Zhang (Supervisor)
 			Prof. Mounir Hamdi
 			Prof. Bo Li
 			Prof. Khaled Ben Letaief (ECE)
 			Prof. Yuguang Fang (Elec. & Comp. Engg.,
 					    Univ. of Florida)


**** ALL are Welcome ****