Abstract
In this paper, we investigate users’ performance under the hybrid spectrum access model in the massive cognitive radio network (CRN), where multiple primary users (PUs) and secondary users (SUs) transmit on the same channel simultaneously. SUs first detect the state of the channel via channel sensing and select an appropriate channel access scheme (either underlay or overlay) for their transmissions based on the outcome of the channel sensing. When at least one PU is active, SUs transmit under the underlay channel access scheme by employing the power control technique to ensure that the interference generated in the primary network is below the pre-defined interference threshold. In the absence of PU, SUs transmit with full transmit power under the overlay channel access scheme, thereby maximizing their throughput. Using the tool of stochastic geometry, we obtained tractable analyses for important metrics such as success probability, throughput, and the average age of information (AoI) in both primary and secondary networks, while capturing the interference between the two networks. The obtained analyses offer an efficient way to understand the metrics of AoI, throughput and success probability in the hybrid spectrum access-based CRN. We further compared users’ performance under the hybrid spectrum access scheme with performances under overlay and underlay spectrum access schemes. The outcome of the numerical simulations shows that the hybrid spectrum access scheme can significantly improve the performance of users in the network, while also capturing more key features of real-life systems.
Highlights
We considered a massive cognitive radio network (CRN) as a network with multiple primary and secondary transmitter-receiver pairs within the Euclidean space as shown in Figure 1, where primary transmitters (PTs) and secondary transmitters (STs) are distributed following two independent homogeneous Poisson point processes (PPPs) (HPPPs) Φ p and Φs of intensities λ p and λs respectively
We provide some details and outcomes of numerical simulations carried out in order to demonstrate the performance of both primary users (PUs) and secondary users (SUs) under the proposed approach
We explored the performance of the hybrid spectrum access mode and compared it with overlay and underlay modes
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The continuous proliferation of wireless communications systems and services implies that the subject of spectrum management and availability continue to attract attentions. Over 25 billion devices are expected to be connected on the internet by the year 2025. A successful communication among these devices requires proper coordination among users on the scarce spectrum resources; investigating the behaviour and performance of users in the cognitive wireless communications networks is a necessity
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