Collaborative Anti-Jamming Broadcast with Uncoordinated Frequency Hopping over USRP

Cognitive radio networks (CRNs) are threatened by smart jammers that aim to block the ongoing transmissions of secondary users according to their transmission patterns obtained from public control channels or compromised secondary users. Without requiring any pre-shared PHY-layer keys at the receivers, the uncoordinated frequency hopping (UFH) technique that was proposed to address smart jammers suffers from a low communication efficiency. In this paper, we develop a UFHbased collaborative broadcast system over universal software radio peripherals (USRPs), which exploits the node cooperation to improve the broadcast efficiency and jamming resistance of CRNs. Experiments are performed over USRPs to evaluate the broadcast performance against smart jammers under various network topologies. We investigate the impact of the CRN bandwidth, the prediction accuracy of smart jammers regarding the CRN frequency hopping pattern, and the jamming power and signal pattern. Experimental results show that the proposed broadcast system is more robust than three benchmark broadcast systems in most jamming scenarios.