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One of the critical problems in the design of an information processing utility that permits flexible sharing of user information is privacy. One solution for this problem is discussed. [ABSTRACT FROM AUTHOR]

Cognitive radio (CR) technology is considered to be an effective solution to allocate spectrum resources, whereas the primary users of a network do not fully utilize available frequency bands. Spectrum auction framework has been recognized as an effective way to achieve dynamic spectrum access. From the perspective of spectrum auction, multi-band multi-user auction provides a new challenge for spectrum management. This paper proposes an auction framework based on location information for multi-band multi-user spectrum allocation. The performance of the proposed framework is compared with that of traditional auction framework based on a binary interference model as a benchmark. Simulation results show that primary users will obtain more total system revenue by selling their idle frequency bands to secondary users and the spectrum utilization of the proposed framework is more effective and fairer. [ABSTRACT FROM AUTHOR]

Abstract: From the unicity and orthogonality properties of chaotic sequences, it is demonstrated that a sum of N chaotic signals generated from a fixed class of chaotic systems is unique. Consequently, within a framework of a multi-user transmission, it is shown that synchronizing N chaotic carriers that emit simultaneously on the same frequency band is feasible. In this paper, the carriers are generated from Chua’s circuits and are modulated in amplitude by the information signal. Demodulation is ensured by the minimization of a cost function. Numerical simulations show that this synchronization method is robust in presence of noise and allows the integration of a high number of users. [Copyright &y& Elsevier]