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Browsing Articles by Author "Adachi, Fumiyuki"

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    Context aware medium access control for buffer-aided multichannel cognitive networks
    (Institute of Electrical and Electronics Engineers Inc., 2016-02-18) Darabi, Mostafa; Maham, Behrouz; Saad, Walid; Mehbodniya, Abolfazl; Adachi, Fumiyuki
    In this paper, a novel context aware medium access control (MAC) scheme is proposed for multichannel buffer-aided cognitive networks. The proposed scheme allows management of the delay of the primary network (PN) and secondary network (SN) more efficiently by exploiting the packets' context. In the proposed multiple access policy, two different context aware approaches for packet prioritization are presented.
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    Joint Machine-Type Device Selection and Power Allocation for Buffer-Aided Cognitive M2M Communication
    (The 26th Personal, Indoor and Mobile Radio Communications Conference (IEEE PIMRC), 2015) Darabi, Mostafa; Maham, Behrouz; Saad, Walid; Mehbodniya, Abolfazl; Adachi, Fumiyuki
    In this paper, a cognitive machine-to-machine (M2M) communication network is considered, in which a cellular network shares the spectrum with the M2M communication network with M machine-type devices (MTDs), one half-duplex relay, and one MTD gateway for data gathering. One key challenge is that in the future 5G wireless networks, there will be billions of those small MTDs, and therefore, a MTD selection protocol is required for managing data transmission between MTDs. A joint buffer-aided MTD selection and power allocation protocol is proposed to maximize the MTDs’ sum-rate provided that the induced interference to the cellular network is limited. In particular, in the proposed scheme, at each time slot and each subcarrier, the cognitive M2M network optimally decides on whether to be silent or to select either the relay or one of the MTDs for data transmission. To this end, for each MTD, there exists a buffer at the relay to avoid data loss. The closed-form expressions for the power coefficients of MTDs are calculated. Simulation results show that the proposed policy improves the sum-rate of the CM2M network in comparison with the other proposed schemes for M2M communication without buffer