Recently, cooperative system is an interesting issue in communication systems. Single mobile antenna can have transmission diversity gain by the cooperative system as multiple input multiple output (MIMO) system. However, the most of the cooperative systems have a problem about the transmission rate loss. In this paper, hierarchical modulation is proposed in order to solve the transmission rate...

In this study, we analyzed an intra-cluster based cooperative energy detection between source (S) and destination (D), the network model consisting of one source, one destination and M number of clusters between the source and destination and each cluster consisting of N number of cognitive relays. We analyzed the performance of inter-cluster and intra-cluster cooperative energy detection. We d...

This work presents a study of detection performance of energy detector in relay based multihop cooperative diversity networks operating over independent Rayleigh fading channels. In particular, upper bound average detection probability expressions are obtained for three scenarios: (i) Multi-hop cooperative relay communication; (ii) Multi-hop cooperative relay communication with direct link and ...

This thesis will study the issue of user cooperation and antenna sharing to improve wireless communication, network (autonomous) time keeping and network (autonomous) topology estimation. Practical schemes are proposed, analyzed and implemented using low cost embedded radios. This thesis tests the following hypothesis: cooperative communication provides for more reliable communication under cer...