Proactive integrated handoff management in cognitive radio mobile ad hoc networks
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RESEARCH
Open Access
Proactive integrated handoff management in cognitive radio mobile ad hoc networks Samad Nejatian1*, Sharifah Kamilah Syed-Yusof1, Nurul Mu'azzah Abdul Latiff1, Vahid Asadpour2 and Haleh Hosseini1
Abstract In cognitive radio networks, the secondary users (SUs) switch the data transmission to another empty spectrum band to give priority to primary users (PUs). In this paper, channel switching in cognitive radio mobile ad hoc networks (CR-MANETs) through an established route is modeled. The probability of channel availability in this route is calculated based on the PU's activity, SU's mobility, and channel heterogeneity. Based on the proposed model, the channel and link availability time are predicted. These predictions are used for channel assignment in the proposed channel allocation scheme. A handoff threshold as well as a life time threshold is used in order to reduce the handoff delay and the number of channel handoffs originating from the short channel usage time. When the channel handoff cannot be done due to the SU's mobility, the local flow handoff is performed to find an appropriate node in the vicinity of a potential link breakage and transfer the current data flow to it. The local flow handoff is performed to avoid possible flow disruption and also to reduce the delay caused by the link breakage. The study reveals that the channel heterogeneity and SU's mobility must be considered as important factors, which affect the performance of the handoff management in the CR-MANETs. The results emphasize on the improvement of the route maintenance probability after using the local flow handoff. It is also stated that the amounts of handoff requirement and handoff delay are decreased after using the predicted channel usage life time and handoff threshold time. Keywords: Cognitive radio; Mobile ad hoc networks; Spectrum handoff; Spectrum management; Spectrum mobility
1 Introduction Over the last few decades, the world has experienced an explosion of the wireless devices. This has led to some spectrum bands being heavily used, especially unlicensed bands, such as ISM bands, which can be attributed to interference and poor network performance. On the other hand, recent studies have shown that a large amount of the licensed spectrum bands remain underutilized and inefficient [1]. Hence, it was concluded that the traditional fixed spectrum allocation approach cannot efficiently regulate the spectrum access any longer. Dynamic spectrum access is an approach that permits wireless devices to use the idle frequency bands, namely spectrum holes, [1] with enabling technology of cognitive radio (CR). CR changes its transmission parameters * Correspondence: [email protected] 1 Faculty of Electrical Engineering, University Technology Malaysia, Skudai 81300, Malaysia Full list of author information is available at the end of the article
based on the interaction with the surrounding environment and allows the secondary user (SU) to share the spectrum when the primary users (PUs) do not use these spectru
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