A Semiblind Two-Way Training Method for Discriminatory Channel Estimation in MIMO Systems

Discriminatory channel estimation (DCE) is a recently developed strategy to enlarge the performance difference between a legitimate receiver (LR) and an unauthorized receiver (UR) in a multiple-input multiple-output (MIMO) wireless system. Specifically, it makes use of properly designed training signals to degrade channel estimation at the UR which in turn limits the UR's eavesdropping capability during data transmission. In this paper, we propose a new two-way training scheme for DCE through exploiting a whitening-rotation (WR) based semiblind method. To characterize the performance of DCE, a closed-form expression of the normalized mean squared error (NMSE) of the channel estimation is derived for both the LR and the UR. Furthermore, the developed analytical results on NMSE are utilized to perform optimal power allocation between the training signal and artificial noise (AN). The advantages of our proposed DCE scheme are two folds: 1) compared to the existing DCE scheme based on the linear minimum mean square error (LMMSE) channel estimator, the proposed scheme adopts a semiblind approach and achieves better DCE performance; 2) the proposed scheme is robust against active eavesdropping with the pilot contamination attack, whereas the existing scheme fails under such an attack.Comment: accepted for publication in IEEE Transactions on Communication

The H

This paper discusses the state feedback H∞ control problem for a class of bilinear stochastic systems driven by both Brownian motion and Poisson jumps. By completing square method, we obtain the H∞ control by solutions of the corresponding Hamilton-Jacobi equations (HJE). By the tensor power series method, we also shift such HJEs into a kind of Riccati equations, and the H∞ control is represented with the form of tensor power series

Enhancing secrecy with sectorized transmission in decentralized wireless networks

In this paper, we combine sectorized transmission with artificial noise to establish secrecy in decentralized wireless networks. The locations of the legitimate nodes and the eavesdroppers are both modeled by homogeneous Poisson point processes. Using sectorized antennas, each legitimate transmitter sends an information signal in the sector which contains its intended receiver, while simultaneously emitting artificial noise in other sectors, in order to provide secrecy against the eavesdroppers. We first separately characterize the reliability performance of the legitimate link and the secrecy performance against malicious eavesdropping. Then, we derive the secrecy transmission capacity to measure the networkwide secrecy throughput. To facilitate the practical system design, we provide a sufficient condition, in terms of the system parameters and constraints, under which a positive secrecy transmission capacity is achievable. The optimal transmit power allocation between the information signal and the artificial noise for achieving the maximal secrecy transmission capacity is also investigated. Our analysis indicates that sectorized transmission provides significant secrecy enhancements in decentralized wireless networks.The work of X. Zhang and M. R. McKay was supported by the Hong Kong Research Grants Council (Grant No. 616312). The work of X. Zhou was supported by the Australian Research Council's Discovery Projects funding scheme (Project No. DP110102548)

L’idée de « deux cités »

L’influence de saint Augustin sur Christine de Pizan est évidente à première vue. D’abord, il l’a inspirée avec le titre de son chef d’œuvre : le De Civitate Dei, Cité de Dieu d’après la plus ancienne traduction française de Raoul de Presles, puisque Christine a nommé son livre le plus célèbre, La Cité des Dames, ouvrage rédigé dix siècles après celui de son prédécesseur. Ensuite, en prenant l’exemple de saint Augustin pour qui l’imputation faite aux chrétiens du désastre du sac de Rome par l..

Traduire les expressions grossières en chinois

Un soir de réveillon, tandis que partout les gens font la fête, Murielle, une femme abandonnée de tous – sa fille suicidée, son petit garçon à la garde du père, sa mère qui la juge, ses hommes envolés et le monde qui la condamne – se laisse aller, dans son désespoir, à son délire intérieur. Voici ce que met en scène Simone de Beauvoir au travers des propos violents, incohérents et ponctués de grossièreté de l’héroïne, dans « Monologue », la deuxième nouvelle du recueil La Femme rompue, paru e..