Improving Spectrum Sensing and Multiuser Cooperation in Wireless Cognitive Radio Networks

PhD Thesis Proposal Defence


Title: "Improving Spectrum Sensing and Multiuser Cooperation in Wireless
Cognitive Radio Networks"

by

Mr. Chengqi Song


Abstract:

Nowadays wireless spectrum resource is more and more scarce because most 
wireless spectrum bands have been allocated to licensed users, however 
measurements show that many bands are very underutilized. To solve this 
problem, Cognitive Radio (CR) is proposed to improve spectrum utility without 
interference to licensed users. CR need to keep aware of wireless environment 
by spectrum sensing and access unused bands without interference to licensed 
users. In this proposal we focus on two important issues in CR networks: 
spectrum sensing and multi-user cooperation. i) Spectrum sensing is the key 
component of CR technology. We improve spectrum sensing by studying spectrum 
usage prediction and cooperative spectrum sensing. Spectrum usage prediction 
can significantly reduce the sensing range basing on history information. We 
conduct a large scale empirical study basing on realworld measurement to reveal 
the predictability and ideal predictors for spectrum usage. We also propose a 
new spectrum sensing scheme assisted with spectrum prediction. Cooperative 
spectrum sensing is introduced to improve sensitivity with spatial diversity. 
We improve it by designing a Carrot-and-Stick based strategy to stimulate 
cooperation, relaxing it into asynchronous mode and introducing multi-channel 
coordination mechanism. ii) Because the wireless environment of CR networks is 
more complicated and unstable comparing with traditional wireless networks, the 
cooperation of multiple users is more critical. Cooperative spectrum sensing is 
a good example and we also study another important problem: stimulating data 
forwarding. We show that the traditional solutions are context-based and our 
new proposed context-free solution is more lightweight and bug-free.


Date:  			Tuesday, 9 March 2010

Time:           	10:30am - 12:30pm

Venue:          	Room 3494
 			lifts 25/26

Committee Members:      Dr. Qian Zhang (Supervisor)
 			Dr. Jogesh Muppala (Chairperson)
 			Dr. Lin Gu
 			Prof. Bo Li


**** ALL are Welcome ****