Reputation-Aware Relay Selection With Opportunistic Spectrum Access: A Blockchain Approach

Abstract

The highly dynamic nature of cognitive radio systems (CR) and their stringent latency requirements pose a major challenge in the realization of efficient intelligent transportation systems. In this paper, we investigate relay selection and opportunistic spectrum access in conjunction with blockchain technology. In particular, we propose a cross-layer method for secure relay selection, where secondary relays (SRs) are granted access to available spectrum bands based on the balance of their respective virtual wallets. These virtual wallets, which are built based on the SRs' secrecy capacity and their behavior in the network, are the predominant factors that allow SRs to participate in an auction model. To quantify the trustworthiness of SRs, we formulate a mathematical framework to evaluate the trust value of each SR, which is then leveraged for rewarding or penalizing the SR. We develop an offline module blockchain framework to store the real-time information of participating relays and make it available for future operations. The information is checked and verified by miners. Our system is able to detect reputable and non-reputable relays in the presence of multiple eavesdroppers. We present a thorough numerical analysis to demonstrate the superiority of the proposed scheme in terms of security, credibility, and integrity. On average, the secrecy capacity rate of the overall system increased by 70% compared to the traditional systems. Further, the propsed model perform better in low SNR compared to traditional one.