In order to mitigate the shortage of wireless spectrum, the appealing concepts of cooperative
communication techniques and cognitive radio (CR) networks have been combined for the …

In cognitive radio networks, primary users can share some licensed spectrums with
secondary users in exchange for cooperation. In this study, an overlay scenario is …

In this dissertation, we study MIMO two-way relay networks consisting of singleantenna
users which wish to exchange information with the help of multiple multiantenna relays. The …

Along with the development of time and the progress of technology and science, the way
people communicate and their lifestyle has changed significantly. Nowadays, people get …

The fundamental problem in multi-cell two-way relaying is low uplink achievable rate due to
the fact that the uplink signal transmitted by a user is significantly contaminated by the …

In this dissertation, two promising technologies which improve the spectrum efficiency in
wireless networks are investigated: cognitive radio (CR) and relay technology. Cognitive …