A QoS-Based Broadcast Protocol for Multi-Hop Cognitive Radio Ad Hoc Networks under Blind Information

Broadcast is an important operation in wireless networks where control information is usually propagated as broadcasts for the realization of most networking protocols. In traditional ad hoc networks, broadcasts are conducted on a common channel which is shared by all nodes in the network. However, in cognitive radio (CR) networks, unlicensed users may observe heterogeneous spectrum availability which is unknown to other users before broadcasts are executed. Thus, it is extremely challenging that broadcasts can be successfully conducted without the spectrum availability information. In addition, since broadcast collisions (i.e., simultaneous receipt of broadcast messages at the same node) often lead to the waste of network resources, they should be efficiently mitigated in multi-hop scenarios. In this paper, a Quality-of-Service (QoS)-based broadcast protocol for multi-hop CR ad hoc networks under blind information is proposed with the aim of high success rate and short broadcast delay. In our design, we do not assume that unlicensed users are aware of the network topology, the spectrum availability information, and time synchronization information. To the best of our knowledge, this is the first paper that investigates the broadcast issue in multi-hop CR ad hoc networks under realistic scenarios. Simulation results show that our proposed broadcast protocol outperforms the random broadcast scheme in terms of higher success rate and shorter average broadcast delay.