In this paper, closed-form expressions for the capacities per unit bandwidth (spectrum efficiency) of Weibull fading channels are derived and plotted for (a) Switch and Stay Combining diversity case and (b) no diversity case for adaptation policies like: (i) Optimal Power and Rate Adaptation policy, (ii) Optimal Rate Adaptation with constant transmit power policy, (iii) Channel Inversion with F...

Image watermarking is a mapping from watermark message to a set of image counterparts, where every version conveys the same meaning with the original image. Since textures that present single perceptual meaning have certain diversity, an intuitive idea of watermarking is to replace the texture region of an image with a similar-looking synthetic texture containing the watermark. We propose a spr...

This paper proposes a transmission capacity model with an overlaid regime that models the cognitive radio technology. We study a case of two coexisting wireless networks (the primary (PR) network and the secondary (SR) network) operating in the same geographical region and sharing the same spectrum and define the transmission capacity as a product of three signal propagation parameters: the den...

We consider the additive white Gaussian noise channels. We prove that the error probability of decoding tends to one exponentially for rates above the capacity and derive the optimal exponent function. We shall demonstrate that the information spectrum approach is quite useful for investigating this problem. Keywords—Additive white Gaussian noise channels, Strong converse theorem, Information s...

Funding information National Science Foundation, Grant/Award Number: CNS-1247955, CNS-1247924; Wireless Engineering Research & Education Center (WEREC), Auburn University Abstract Femtocells are small, low-power cellular base stations with high potential for coverage extension and offloading voice and wireless data. In this paper, we study the problem of joint access control and spectrum resour...

In this paper, we discuss on two important issues through the realization of global personal communication networks with low earth orbital (LEO) satellites. The first issue is the selection of an effective multiple access scheme which can utilize the limited spectrum allocated to these systems. In this way, we focus on the schemes based on spread spectrum techniques and explain their unique cha...

The surge of mobile devices such as smartphone and tablets requires additional capacity. To achieve ubiquitous and high data rate Internet connectivity, effective spectrum sharing and utilization of the wireless spectrum carry critical importance. In this paper, we consider the use of unlicensed LTE (LTE-U) technology in the 3.5 GHzCitizens BroadbandRadio Service (CBRS) band and develop amultia...

On the Capacity of Underlay Cognitive Radio Systems Lokman Sboui Due to the scarcity of frequency spectrum in view of the evolution of wireless communication technologies, the cognitive radio (CR) concept has been introduced to efficiently exploit the available spectrum. This concept consists in introducing unlicensed/secondary users (SU’s) in existing networks to share the spectrum of licensed...

The overlay of an intelligent frequency diversity spread spectrum system (FDSS) on the (GSM) system is studied. The uplink capacity of both systems is given using a model of 36 hexagonal macrocells. Performance of GSM and FDSS users is investigated. An original GSM system with 48 users/macrocell can be substituted by a mixed system, which has GSM system capacity of 48 users/macrocell and FDSS s...

-Several new results on binary ( d , k ) codes are given. First, a new derivation for the capacity of these codes based upon information theoretic principles is given. Based upon this result the spectrum of a ( d , k ) code is computed. Finally, the problem of computing the capacity of the binary symmetric channel under the condition that the input sequences satisfy the ( d , k ) constraint is ...