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In mobile ad-hoc cognitive radio networks (CRNs), end-to-end paths with available spectrum bands for secondary users may exist temporarily, or may never exist, due to the dynamism of the primary user activities. Traditional CRN routing algorithms, which typically ignore the intermittent connectivity of network topology, and traditional mobility-assisted routing algorithms, which generally overlook the spectrum availability, are obviously unsuitable. To tackle this challenge, we propose a Mobility-Assisted Routing algorithm with Spectrum Awareness (MARSA) to select relays based on not only the probability that a node meets the destination but also the chance at which there exists at least one available channel when they meet. To the best of our knowledge, this paper is the first to bring the idea of mobility-assisted routing to deal with the intermittently connected attribute of mobile ad-hoc CRNs, and the first to enhance the mobility-assisted routing by considering the temporal , spatial, and spectrum domains at the same time. Our simulation results demonstrate the superiority of MARSA over traditional algorithms in intermittently connected mobile CRNs. [ABSTRACT FROM AUTHOR]

The advantages brought by opportunistic data delivery make mobile opportunistic networking a promising technology for big data computing. Thus, it is important to study the potential of mobile opportunistic networks in supporting big data applications by analyzing their fundamental data dissemination properties. However, such an analysis is nontrivial as a large dimension of elements may affect the data spreading behavior in mobile opportunistic networks. In this article, we first outline the challenges of analyzing the potential of mobile opportunistic networks for big data applications. Then we survey the state-of-the-art analytical results on data dissemination properties in mobile opportunistic networks. Finally, we summarize our analytical results and present a few open research issues that may foster future research endeavors on mobile opportunistic networks to support big data applications. [ABSTRACT FROM PUBLISHER]

The benefits of cognitive radio networking (CRN) have been well recognized with the emerging wireless applications in recent years. While many existing works assume that the secondary transmissions are negative interferences to the primary users (PUs), in this paper, we take secondary users (SUs) as positive potential cooperators for the PUs. In particular, we consider the problem of cooperative relay selection, in which the PUs actively select appropriate SUs as relay nodes to enhance their transmission performance. The most critical challenge for such a problem is how to select a relay efficiently. Due to the potentially large number of SUs, it is infeasible for a PU to first scan all the SUs and then pick the best. Basically, the PU transmitter intends to observe the SUs sequentially. After observing an SU, the PU needs to make a decision regarding whether to terminate its observation and use the current SU as its relay or to skip it and observe the next SU. We address this problem by using the optimal stopping theory and derive the optimal stopping rule. We also discuss the optimal observation order of the SUs and analyze the collision probability. To evaluate the performance of our proposed scheme, we compare our optimal stopping policy with the random selection policy through simulation study, and the results demonstrate the superiority of our policy. Extensive simulation study is conducted to investigate the impact of different parameters on the system performance, and the results indicate that our algorithm can satisfy different system requirements by carefully tuning the corresponding system parameters. [ABSTRACT FROM PUBLISHER]

This article considers the routing issues for user-centric network applications. User-centric network routing is a challenging problem because there may not always exist a complete stable path from an information source to its destination. In this article, we provide a brief overview on the state-of-the-art user-centric network routing schemes and discuss their performance in terms of data delivery ratio and delivery latency. We also present a few open research issues that are critical to user-centric network applications. [ABSTRACT FROM PUBLISHER]