Impact of Collaborative Spectrum Sensing and Nakagami-m Fading on the Transmission Capacity of Cognitive Radio Networks

—Spectrum sharing has become a promising approach to meet the rapid development of cognitive radio technologies and improving the spectrum utilization and mitigate the spectrum starvation problems. This paper discusses the achievable transmission capacity of secondary users in a cognitive radio network employing collaborative spectrum sensing and undergoes Nakagami-m fading channel. Efficient and spectrum detection of licensed user is crucial to a successful deployment of cognitive radio. However, spectrum detection in mobile fading channels is challenging and it affects the detection performance. The proposed system model consists of a primary or licensed network, secondary users' network and infrastructure collaborative spectrum sensor, each with independent and none identical propagation channel model that follow Nakagami-m fading statistics. We develop a new mathematical framework and derive new expressions for the transmission capacity of secondary users with all channels undergoing Nakagami-m fading with non-integer fading parameters. Among numerus combining methods, we consider the impact of soft and hard decision combining of the spectrum detector on the transmission capacity. Moreover, we derived exact and alternative expressions of the transmission capacity for integer-fading parameter cases. The pertinent numerical results are generated to evaluate our analytical solution for the transmission capacity under various scenarios such as primary network traffic, channel fading parameters and collaborative sensing methods. `