Penn State College of Communications

About: Penn State College of Communications is a based out in . It is known for research contribution in the topics: Relay & Cognitive radio. The organization has 2106 authors who have published 2119 publications receiving 24693 citations.

Improved exponential stability criteria for uncertain neutral system with nonlinear parameter perturbations

Abstract: This paper investigates the problem of robust exponential stability for neutral systems with time-varying delays and nonlinear perturbations. Based on a novel Lyapunov functional approach and linear matrix inequality technique, a new delay-dependent stability condition is derived. Since the model transformation and bounding techniques for cross terms are avoided, the criteria proposed in this paper are less conservative than some previous approaches by using the free-weighting matrices. One numerical example is presented to illustrate the effectiveness of the proposed results.

iMap: A Crowdsensing Based System for Outdoor Radio Signal Strength Map

Abstract: With the ubiquity of mobile appliances, efficient wireless access has become an urgent need for mobile users. Efficient wireless access requires accurate radio signal maps. Unfortunately, most of solutions could not be applied to large-scale urban space. Crowdsensing schemes could leverage the smartphone to sense WiFi signals, but could not provide accurate map because of the intolerable noises in mobile devices. Even worse, device heterogeneity makes the noise taming more intractable. Thus how to build accurate radio signal map with heterogeneous devices, especially in mobile crowdsensing is a major challenge. In this work, we build an accurate WiFi signal in geographical domain with iMap, a crowdsensing system leveraging heterogeneous smart devices to tame device noise ambiently in large-scale urban space. First of all, we deployed our system in typical urban area, and collect the real trace data with heterogeneous smart phones. After that, we make a synthetic analysis over the collected data, and find that, (1) although the noise is intolerable, it could be fitted to a statistical model fairly well, (2) although the noise model varies across smartphone types, the relative value between smart phones could be modeled. Leveraging this fundamental observation, we construct and implement an accurate RSS map with model-driven approach for taming heterogeneous noise, and geo-tagged measurements could be tamed for accurate RSS map. Experimental evaluations further validate our design.

Robust Beamforming in Multibeam Satellite Systems With Non-Orthogonal Multiple Access

Abstract: In this letter, we investigate the beamforming optimization problem in a non-orthogonal multiple access (NOMA) based multibeam satellite system. The design key is to minimize the transmit power on-board the multibeam satellite system with the perfect and imperfect channel state information (CSI), while meeting the quality of service (QoS) for satellite users. Owing to the intractability and non-convexity of the original optimization problem induced by the user’s CSI uncertainty, we consider the robust beamforming scheme to convert the original optimization problem into a tractable convex optimization problem by S-Procedure and semidefinite relaxation (SDR) techniques and obtain the optimal solutions. Finally, numerical simulations demonstrate the superiority and validity of the proposed beamforming optimization algorithms.

Quantitative investigation into the use of resonant magneto-inductive links for efficient wireless power transfer

Abstract: The use of resonant magneto-inductive links is an efficient technique to transfer power over midranges in the field of wireless power transfer (WPT). Power transfer efficiency (PTE) and power delivered to the load (PDL) are two important indicators of power transmission for a WPT system. A predetermined amount of PDL need be generated at maximum PTE for practical application in a WPT system; thus, the authors focus on maximising PTE and a predetermined amount of PDL for transfer in this study. First, load-matching conditions are presented for maximum PTE transfer though circuit theory-based analyses. Then, a new tuning method is proposed to transfer a predetermined amount of PDL which can be controlled by source-matching distance at maximum PTE. The relations between the loss of a load-matching resonator and the PTE (or PDL) of a correspondingly unmatched system are derived though analyses as well. Finally, the calculated results of the design examples are verified through electromagnetic simulations and experimental measurements.