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— Spectrum is one of the most precious radio resource. With the increasing demand for wireless communication, efficiently using the spectrum resource has become an essential issue. With the Federal Communications Commission's (FCC) spectrum policy reform, secondary spectrum sharing has gained increasing interest. One of the policy reforms introduces the(More)
—This paper proposes an optimal maximum a poste-riori probability decoder for variable-length encoded sources over binary symmetric channels that uses a novel state-space to deal with the problem of variable-length source codes in the decoder. This sequential, finite-delay, joint source-channel decoder delivers substantial improvements over the conventional(More)
— In this paper, we study the denial-of-service (DoS) attack on secondary users in a cognitive radio network by primary user emulation (PUE). Most approaches in the literature on primary user emulation attacks (PUEA) discuss mechanisms to deal with the attacks but not analytical models. Simulation studies and results from test beds have been presented but(More)
— In this paper, we present an analytical model as well as a practical mechanism to detect denial of service (DoS) attacks on secondary users in dynamic spectrum access (DSA) networks. In particular, we analyze primary user emulation attacks (PUEA) in cognitive radio networks without using any location information and therefore can do away with any(More)
— Encryption is one of the fundamental technologies that is used in digital rights management. Unlike ordinary computer applications, multimedia applications generate large amounts of data that has to be processed in real time. So, a number of encryption schemes for multimedia applications have been proposed in recent years. We analyze the following(More)
Shannon's source-channel separation theorem holds only under asymptotic conditions, where both source and channel codes are allowed innnite length and complexity, which is not possible in practice. This observation has led to the increasing popularity of joint source-channel encoding and decoding schemes as viable alternatives for achieving reliable(More)
Minimizing power consumption is crucial in battery power-limited secure wireless mobile networks. In this paper, we (a) introduce a hardware/software set-up to measure the battery power consumption of encryption algorithms through real-life experimentation, (b) based on the profiled data, propose mathematical models to capture the relationships between(More)