309 research outputs found
Bit-Interleaved Coded Energy-Based Modulation with Iterative Decoding
This paper develops a low-complexity near-optimal non-coherent receiver for a
multi-level energy-based coded modulation system. Inspired by the turbo
processing principle, we incorporate the fundamentals of bit-interleaved coded
modulation with iterative decoding (BICM-ID) into the proposed receiver design.
The resulting system is called bit-interleaved coded energy-based modulation
with iterative decoding (BICEM-ID) and its error performance is analytically
studied. Specifically, we derive upper bounds on the average pairwise error
probability (PEP) of the non-coherent BICEM-ID system in the feedback-free (FF)
and error-free feedback (EFF) scenarios. It is revealed that the definition of
the nearest neighbors, which is important in the performance analysis in the FF
scenario, is very different from that in the coherent BICM-ID counterpart. The
analysis also reveals how the mapping from coded bits to energy levels
influences the diversity order and coding gain of the BICEM-ID systems. A
design criterion for good mappings is then formulated and an algorithm is
proposed to find a set of best mappings for BICEM-ID. Finally, simulation
results corroborate the main analytical findings
Optimum Transmission Through the Multiple-Antenna Gaussian Multiple Access Channel
"(c) 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works."[EN] This paper studies the optimal points in the capacity region of Gaussian multiple access channels (GMACs) with constant fading, multiple antennas, and various power constraints. The points of interest maximize general rate objectives that arise in practical communication scenarios. Achieving these points constitutes the task of jointly optimizing the timesharing parameters, the input covariance matrices, and the order of decoding used by the successive interference cancellation receiver. To approach this problem, Carathéodory s theorem is invoked to represent time-sharing and decoding orders jointly as a finite-dimensional matrix variable. This variable enables us to use variational inequalities to extend results pertaining to problems with linear rate objectives to more general, potentially nonconvex, problems, and to obtain a necessary and sufficient condition for the optimality of the transmission parameters in a wide range of problems. Using the insights gained from this condition, we develop and analyze the convergence of an algorithm for solving, otherwise daunting, GMAC-based optimization problems.D. Calabuig was supported by Marie Curie International Outgoing Fellowship within the European Commission, Research Executive Agency, through the COMIC Project under Grant 253990. R. H. Gohary and H. Yanikomeroglu were supported in part by Huawei Canada Company, Ltd., and in part by the Ontario Ministry of Economic Development and Innovations within the Ontario Research Fund through the Research Excellence Program. This paper was presented at the 2013 IEEE International Symposium on Information Theory and the 2014 IEEE International Workshop on Signal Processing Advances in Wireless Communications.Calabuig Soler, D.; Gohary, RH.; Yanikomeroglu, H. (2016). Optimum Transmission Through the Multiple-Antenna Gaussian Multiple Access Channel. IEEE Transactions on Information Theory. 62(1):230-243. https://doi.org/10.1109/TIT.2015.2502244S23024362
On the Performance of Selection Relaying
Interest in selection relaying is growing. The recent developments in this
area have largely focused on information theoretic analyses such as outage
performance. Some of these analyses are accurate only at high SNR regimes. In
this paper error rate analyses that are sufficiently accurate over a wide range
of SNR regimes are provided. The motivations for this work are that practical
systems operate at far lower SNR values than those supported by the high SNR
analysis. To enable designers to make informed decisions regarding network
design and deployment, it is imperative that system performance is evaluated
with a reasonable degree of accuracy over practical SNR regimes. Simulations
have been used to corroborate the analytical results, as close agreement
between the two is observed.Comment: Proceedings of the 2008 IEEE Vehicular Technology Conference,
Calgary, Alberta, September 21-24, 200
Центр міжкультурної толерантності як інноваційний ресурс щодо формування громадянської культури у студентів
У статті з‘ясовано поняття «міжкультурна толерантність», проаналізовано останні дослідження щодо даної теми; обґрунтовано доцільність поєднання навчального процесу з позанавчальною діяльністю студентів (науково-дослідна, виховна, волонтерська види діяльності), зокрема, її презентовано на прикладі діяльності Центру міжкультурної толерантності ЖДУ ім. І.Франка. Крім того, описані основні напрацювання Центру, в яких втілюється загальна мета роботи Центру міжкультурної толерантності
Optimization of Discrete Power and Resource Block Allocation for Achieving Maximum Energy Efficiency in OFDMA Networks
Most of the resource allocation literature on the energy-efficient orthogonal frequency division multiple access (OFDMA)-based wireless communication systems assume continuous power allocation/control, while, in practice, the power levels are discrete (such as in 3GPP LTE). This convenient continuous power assumption has mainly been due to either the limitations of the used optimization tools and/or the high computational complexity involved in addressing the more realistic discrete power allocation/control. In this paper, we introduce a new optimization framework to maximize the energy efficiency of the downlink transmission of cellular OFDMA networks subject to power budget and quality-of-service constraints, while considering discrete power and resource blocks (RBs) allocations. The proposed framework consists of two parts: 1) we model the predefined discrete power levels and RBs allocations by a single binary variable and 2) we propose a close-to-optimal semidefinite relaxation algorithm with Gaussian randomization to efficiently solve this non-convex combinatorial optimization problem with polynomial time complexity. We notice that a small number of power levels suffice to approach the energy efficiency performance of the continuous power allocation. Based on this observation, we propose an iterative suboptimal heuristic to further reduce the computational complexity. Simulation results show the effectiveness of the proposed schemes in maximizing the energy efficiency, while considering the practical discrete power levels
Концепції мовної гри як теоретичні засади організації навчально-ігрової діяльності
У статті розглянуто лінгвофілософські й лінгвістичні концепції мовної гри як підґрунтя організації навчально-ігрової діяльності в системі українськомовної освіти. На основі наукового осмислення окреслено зміст понять "гра", "навчально-ігрова діяльність", "мовна гра". Шляхом аналізу наукової літератури й синтезу теоретичних ідей визначено принципи побудови й реалізації навчально-методичної системи, спрямованої на формування мовної особистості школяра в навчально-ігровій діяльності
Дослідження мотиваційних чинників професійного становлення вчителя
This paper studies two-hop cooperative demodulate-and-forward relaying using multiple relays in wireless networks. A threshold based relay selection scheme is considered, in which the reliable relays are determined by comparing source-relay SNR to a threshold, and one of the reliable relays is selected by the destination based on relay-destination SNR. The exact bit error rate of this scheme is derived, and a simple threshold function is proposed. It is shown that the network achieves full diversity order (N +1) under the proposed threshold, where N is the number of relays in the network. Unlike some other full diversity achieving protocols in the literature, the requirement that the instantaneous/average SNRs of the source-relay links be known at the destination is eliminated using the appropriate SNR threshold
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