Throughput, delay and collision probability are all the important performance for cognitive radio networks. This paper proposes a state transition model and analyzes the performances of the cognitive radio networks with spectrum sensing and access operate simultaneously and conventional cognitive radio networks. The closed form expressions of the throughput, delay and collision probability in two sensing modes are derived. It is showed that the cognitive radio networks with spectrum sensing and access operate simultaneously has obvious advantage over the conventional one in the throughput, delay and collision probability. Simulation results verify the theoretical analysis.
In this paper, the resource allocation in an underlay cognitive radio network is considered, in which the SUs can operate on the same spectrum band with the primary users simultaneously. In order to maximize the total throughput of SUs, an optimal selection matching (OSM) algorithm is proposed to allocate the resource in the underlay cognitive radio network. It makes every SU find the satisfied spectrum resource, and meanwhile the interference from SUs is induced. Simulation results show that the proposed algorithm has the significant improvement in total throughput compared with others.
Cognitive radio networks have wide applications in the smart home, personal communications and other wireless communication. Spectrum sensing is the main challenge in cognitive radios. This paper proposes a new spectrum sensing algorithm which is based on the autocorrelation energy of signal received. By taking the autocorrelation energy of the received signal as the statistics of spectrum sensing, the effect of the channel noise on the detection performance is reduced. Simulation results show that the algorithm is effective and performs well in low signal-to-noise ratio. Compared with the maximum generalized eigenvalue detection (MGED) algorithm, function of covariance matrix based detection (FMD) algorithm and autocorrelation-based detection (AD) algorithm, the proposed algorithm has 2 ~ 11 dB advantage.