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Broadcasting 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) ad hoc networks, unlicensed users may observe heterogeneous spectrum availability, which is unknown to other unlicensed users before the control information was broadcast. Thus, it is extremely challenging that broadcasts can be successfully conducted without knowing the spectrum availability information in advance. In addition, since broadcast collisions (i.e., simultaneous reception of broadcast messages at the same node) often lead to the waste of network resources, they should be efficiently mitigated in multihop scenarios. In this paper, a quality-of-service (QoS)-based broadcast protocol under Blind Information for multihop CR ad hoc networks, i.e., \QB^2\IC, is proposed with the aim of having a 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 multihop CR ad hoc networks under blind information. Simulation results show that our proposed \QB^2\IC protocol outperforms other broadcast schemes in terms of a higher success rate and shorter average broadcast delay. [ABSTRACT FROM PUBLISHER]

The rapid growth of the Internet has led to the anticipated depletion of addresses in the current version of the Internet Protocol (IP), i.e., IPv4. This depletion has given rise to a newer version of the IP, i.e., IP version 6 (IPv6). IPv6 provides sufficient address space to meet the predicted increase of the Internet. Since IPv4 has already widely been deployed, it is required that the existing IPv4 and the newly added IPv6 can coexist and interoperate. Due to the incompatibility of the IPv4 and IPv6 headers, various mechanisms have been proposed to support the interoperability between IPv4 and IPv6. However, they are mostly designed for a static environment. Mobility support of mobile terminals in a mixed IPv4/IPv6 environment remains largely unexplored. It introduces additional overhead and delay to communications. In this paper, we analyze various handoff scenarios for a dual-stack mobile node with a predominant IPv6 home address roaming in a mixed IPv4/IPv6 environment. We investigate how handoffs can be supported and derive the handoff procedures for all scenarios. In addition, we analyze the impact of mobility support on the system performance in terms of handoff-signaling cost, handoff delay, and handoff-failure probability using our designed analytical models. Different traffic and mobility patterns are taken into account in the performance analysis. Numerical results are provided to demonstrate the performance of all handoff scenarios. Conclusions from this study can give great in-depth understanding and insights into designing new cost-effective mobility support mechanisms for IPv4/IPv6 transition and interoperability. [ABSTRACT FROM AUTHOR]