Preamble design for LS channel estimation in OFDM/OQAM cooperative systems is investigated in this paper. A simple but important setup is considered, consisting of a pair of single-antenna terminals (source and destin...
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Preamble design for LS channel estimation in OFDM/OQAM cooperative systems is investigated in this paper. A simple but important setup is considered, consisting of a pair of single-antenna terminals (source and destination) assisted in their communication by an AF relay and following a well-established two-phase transmission protocol. The so-called sparse preamble case (i.e., pilot tones surrounded by nulls) was recently addressed and the optimal design - in the sense of minimum MSE subject to transmit energy constraints - was shown to coincide with the one for CP-OFDM, thus resulting in no performance gains from the adoption of OFDM/OQAM. In order to complete this study and exhibit the possibilities of OFDM/OQAM to outperform CPOFDM, the so-called full preamble design (i.e., with all tones carrying pilot symbols) is addressed in this paper. The results are in line with the corresponding design for single-link systems, where the interference among pilots is positively exploited to provide significant performance gains over CP-OFDM. As a byproduct, the solution for cooperative CP-OFDM is also given, through its connection to OFDM/OQAM. The presented simulation results corroborate the analysis, demonstrating superior performance over CP-OFDM for both mildly and highly frequency selective channels and at practical SNR values.
An adaptive supervisory switching control scheme for nonlinear uncertain systems is developed. Such a scheme comprises: a family of nonlinear candidate controllers, designed using a convex control design methodology;a...
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ISBN:
(纸本)9781467357159
An adaptive supervisory switching control scheme for nonlinear uncertain systems is developed. Such a scheme comprises: a family of nonlinear candidate controllers, designed using a convex control design methodology;and a Lyapunovbased switching criterion that orchestrates which of the candidate controllers should be put in feedback with the uncertain plant. The family of candidate controllers is designed in such a way that, for every portion of the uncertainty set there is one Lyapunov function whose derivative is decreasing with a prescribed rate. Such Lyapunov functions are used by the switching logic to assess which is the most suitable controller to be put in feedback. The resulting scheme guarantees semi-global stability with desired transient performance, in terms of decaying rate of the derivative of the Lyapunov function.
Ontologies provide a formal approach to knowledge representation suitable for digital content annotation. In the context of image annotation a variety of ontology-based tools has been proposed. Most of them enable man...
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Five teams participated in the Multi-Agent Programming Contest in 2013: All of them gained experience in 2012 already. In order to better understand which paradigms they used, which techniques they considered importan...
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Denser transistor integration has enabled the fabrication of multi-tile chips, however, at the expense of higher susceptibility to defects and wear-out. Metal wires comprising the links of Networks-on-Chip (NoCs) are ...
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The major goal of transfer learning is to transfer knowledge acquired on a source task in order to facilitate learning on another, different, but usually related, target task. In this paper, we are using neuroevolutio...
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In this paper, we detail the implementation of a self-organized GMPLS network using the DRAGON software suite to introduce service awareness in a GMPLS network. DRAGON daemon has been extended to support anycast routi...
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Fuzzy Cognitive Map (FCM) is an efficient knowledge representation and reasoning method, which is based on human knowledge and experience. In this work, a FCM model is constructed to represent users' perceptions o...
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Given a large social graph, like a scientific collaboration network, what can we say about its robustness? Can we estimate a robustness index for a graph quickly? If the graph evolves over time, how these properties c...
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The purpose of this paper is to review existing sensor and sensor network ontologies to understand whether they can be reused as a basis for a manufacturing perception sensor ontology, or if the existing ontologies ho...
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The purpose of this paper is to review existing sensor and sensor network ontologies to understand whether they can be reused as a basis for a manufacturing perception sensor ontology, or if the existing ontologies hold lessons for the development of a new ontology. We develop an initial set of requirements that should apply to a manufacturing perception sensor ontology. These initial requirements are used in reviewing selected existing sensor ontologies. Additionally, we present our developed sensor ontology thus far that incorporates a refined list of requirements. This paper describes 1) extending and refining the requirements; 2) proposing hierarchical structures for verifying the purposes of the ontology; 3) choosing appropriate tools and languages (e.g., OWL (Web Ontology Language) [1] and SensorML (Sensor Markup Language) [2]) to support such an ontology; and 4) extending the Semantic Sensor Network (SSN) ontology with a set of refined requirements (i.e., our developed ontology). This work will be proposed as a standard within the IEEE (Institute of Electrical and Electronics Engineers) Robotics and Automation Society (RAS) Ontologies for Robotics Automation (ORA) Working Group [3].
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