Boosting Throughput in Cache-Enabled Cognitive Radio Networks via Interference Cancellation

Abstract

In this paper, we study the mechanism design of opportunistic spectrum access (OSA) in cache-enabled cognitive radio (CR) networks based on interference cancellation (IC). Particularly, we propose an IC-based OSA protocol under which a secondary transmit device (STx) can access the spectrum when it is detected in either the “actual” spatial spectrum hole of the primary network or the “virtual” spatial spectrum hole created by utilizing the technique of IC at the primary receive devices (PRxs) with the cached content as side information. To assess the effectiveness of the proposed IC-based OSA protocol, we leverage tools from stochastic geometry to develop an analytical framework that provides a comprehensive characterization of the cache-enabled CR network. Specifically, we derive closed-form expressions for the transmission probabilities of PRxs and STxs, respectively. Building upon the analytical results, we characterize the conditional distributions of the point processes formed by the active STxs and/or primary transmit devices (PTxs) given a typical PRx/secondary receive device (SRx) situated at the origin. Finally, based on the derived conditional distributions of the active PTxs and STxs, we evaluate the coverage probabilities and thereby the successful content delivery probability of the primary and secondary networks. We conduct simulations to corroborate the effectiveness of our solutions, which also demonstrate the significant performance gain achieved by the proposed IC-based OSA protocol over the baseline schemes.