The topic of cognitive radios has been garnering a great deal of attention in the past several years. Opinions regarding the level of sophistication necessary to qualify a system as cognitive vary widely, and discussions have ensued regarding this technology. The software defined radio forum is also involved and has working group activity in the area of cognitive radio. Some of the working grou...

Cognitive radio networks sense spectrum occupancy and manage themselves to operate in unused bands without disturbing licensed users. The detection capability of a radio system can be enhanced if the sensing process is performed jointly by a group of nodes so that the effects of wireless fading and shadowing can be minimized. However, taking a collaborative approach poses new security threats t...

To encounter the emergent necessity of radio spectrum, which is a limited natural resource, proper utilization of the radio spectrum is a must. Introduction of cognitive radio networks can play a vital role to solve the spectrum scarcity. Cognitive radio uses an open spectrum allocation technique to make more efficient utilization of the wireless radio spectrum and reduce the bottleneck on the ...

Cognitive radio represents an efficient way to utilize the available spectrum in Wireless networks by offering the unlicensed users (Secondary users) the opportunity to use an available spectrum for the licensed users (Primary users) when they are not active. In this paper, some cognitive MAC protocols are discussed with a brief introduction to Multi Channel MAC protocols.

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in this paper, an interference management for multi-beam satellite network to enhance spectral efficiency is studied. first, a two-satellite for future generation satellite network using cognitive radio technology is provided.this network is composed of a secondary satellite and aprimary satellite where the primary satellite system does not suffer from severe destructive interferences coming fr...