**Outage Performance Analysis of Underlay Cognitive Radio Networks with Decode‐and‐Forward Relaying**

Mustafa Namdar and Arif Basgumus

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.69244

#### Abstract

In this chapter, we evaluate the outage performance of decode-and-forward relaying in cognitive radio networks over Rayleigh fading channels, subject to the relay location for a secondary user. In particular, we obtain the optimal relay location in wireless communications systems for the cognitive radio networks, using differential evolution optimization algorithm. Then, we investigate the optimal transmission rate of the secondary user. We present the numerical results to validate the proposed theoretical analysis and to show the effects of the Rayleigh fading channel parameters for the whole system performance.

Keywords: cognitive radio networks, decode-and-forward relaying, differential evolution optimization algorithm, optimal relay location, outage probability
