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Capacity Performance Analysis of M-ary PPM TH-UWB Systems in the Presence of Narrowband Interference
Nikos V. Kokkalis,P. Takis Mathiopoulos,George K. Karagiannidis,Christos S. Koukourlis 한국통신학회 2008 Journal of communications and networks Vol.10 No.3
The capacity of ultra-wideband (UWB) systems in presence of narrowband interference (NBI) is studied. By appropriately modifying the Shannon capacity formula, an analytical expression for the capacity ofM-ary pulse position modulation (PPM) signals in the presence of NBI is obtained. Performance evaluation results for the capacity of such signals as a function of the NBI carrier frequency and power are also presented.
Capacity Performance Analysis of M-ary PPM TH-UWB Systems in the Presence of Narrowband Interference
Kokkalis, Nikos V.,Mathiopoulos, P. Takis,Karagiannidis, George K.,Koukourlis, Christos S. The Korea Institute of Information and Commucation 2008 Journal of communications and networks Vol.10 No.3
The capacity of ultra-wideband (UWB) systems in presence of narrowband interference (NBI) is studied. By appropriately modifying the Shannon capacity formula, an analytical expression for the capacity of M-ary pulse position modulation (PPM) signals in the presence of NBI is obtained. Performance evaluation results for the capacity of such signals as a function of the NBI carrier frequency and power are also presented.
Enhancing PHY Security of Cooperative Cognitive Radio Multicast Communications
Nguyen, Van-Dinh,Duong, Trung Q.,Shin, Oh-Soon,Nallanathan, Arumugam,Karagiannidis, George K. IEEE 2017 IEEE transactions on cognitive communications and Vol.3 No.4
<P>In this paper, we propose a cooperative approach to improve the security of both primary and secondary systems in cognitive radio multicast communications. During their access to the frequency spectrum licensed to the primary users, the secondary unlicensed users assist the primary system in fortifying security by sending a jamming noise to the eavesdroppers, while simultaneously protect themselves from eavesdropping. The main objective of this paper is to maximize the secrecy rate of the secondary system, while adhering to all individual primary users’ secrecy rate constraints. In the case of active eavesdroppers and perfect channel state information (CSI) at the transceivers, the utility function of interest is nonconcave and the involved constraints are nonconvex, and thus, the optimal solutions are troublesome. To solve this problem, we propose an iterative algorithm to arrive at least to a local optimum of the original nonconvex problem. This algorithm is guaranteed to achieve a Karush–Kuhn–Tucker solution. Then, we extend the optimization approach to the case of passive eavesdroppers and imperfect CSI knowledge at the transceivers, where the constraints are transformed into a linear matrix inequality and convex constraints, in order to facilitate the optimal solution.</P>