Cognitive radios utilize spectrum sensors to provide information about the surrounding radio environment. This enables cognitive radios to communicate at the same frequency bands with existing (primary) radio systems, and thereby improve the utilization of spectral resources. Furthermore, the spectrum sensor must be able to guarantee that the cognitive radio devices do not interfere with […]
Cognitive radio is a promising solution to the problem of spectrum scarcity by means of allowing secondary radio networks access the spectrum opportunistically. One of the most important issues in cognitive radio is how to detect existing over-the-air signals reliably. Not a few literatures have reported that signals could be detected via their inherent or […]
Spectrum sensing is a key function of Cognitive Radio (CR) networks. An accurate spectrum sensing scheme can improve spectrum utilization. But, in practice, detection performance is often degraded with multipath fading, shadowing and receiver uncertainty issues. To overcome the impact of these issues, Collaborative Spectrum Sensing (CSS) has been shown to be an effective approach […]
In this paper, dual-hops and multi-hops cognitive radio Ad Hoc networks has been considered. It is vital mentioning that the primary user interference effect on the secondary user has also been considered. The design of the problem is to achieve an optimal solution for channel allocation and power in dual and multi hop in Cognitive […]
