24 research outputs found

    Resource allocation technique for powerline network using a modified shuffled frog-leaping algorithm

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    Resource allocation (RA) techniques should be made efficient and optimized in order to enhance the QoS (power & bit, capacity, scalability) of high-speed networking data applications. This research attempts to further increase the efficiency towards near-optimal performance. RA’s problem involves assignment of subcarriers, power and bit amounts for each user efficiently. Several studies conducted by the Federal Communication Commission have proven that conventional RA approaches are becoming insufficient for rapid demand in networking resulted in spectrum underutilization, low capacity and convergence, also low performance of bit error rate, delay of channel feedback, weak scalability as well as computational complexity make real-time solutions intractable. Mainly due to sophisticated, restrictive constraints, multi-objectives, unfairness, channel noise, also unrealistic when assume perfect channel state is available. The main goal of this work is to develop a conceptual framework and mathematical model for resource allocation using Shuffled Frog-Leap Algorithm (SFLA). Thus, a modified SFLA is introduced and integrated in Orthogonal Frequency Division Multiplexing (OFDM) system. Then SFLA generated random population of solutions (power, bit), the fitness of each solution is calculated and improved for each subcarrier and user. The solution is numerically validated and verified by simulation-based powerline channel. The system performance was compared to similar research works in terms of the system’s capacity, scalability, allocated rate/power, and convergence. The resources allocated are constantly optimized and the capacity obtained is constantly higher as compared to Root-finding, Linear, and Hybrid evolutionary algorithms. The proposed algorithm managed to offer fastest convergence given that the number of iterations required to get to the 0.001% error of the global optimum is 75 compared to 92 in the conventional techniques. Finally, joint allocation models for selection of optima resource values are introduced; adaptive power and bit allocators in OFDM system-based Powerline and using modified SFLA-based TLBO and PSO are propose

    Energy efficiency in short and wide-area IoT technologies—A survey

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    In the last years, the Internet of Things (IoT) has emerged as a key application context in the design and evolution of technologies in the transition toward a 5G ecosystem. More and more IoT technologies have entered the market and represent important enablers in the deployment of networks of interconnected devices. As network and spatial device densities grow, energy efficiency and consumption are becoming an important aspect in analyzing the performance and suitability of different technologies. In this framework, this survey presents an extensive review of IoT technologies, including both Low-Power Short-Area Networks (LPSANs) and Low-Power Wide-Area Networks (LPWANs), from the perspective of energy efficiency and power consumption. Existing consumption models and energy efficiency mechanisms are categorized, analyzed and discussed, in order to highlight the main trends proposed in literature and standards toward achieving energy-efficient IoT networks. Current limitations and open challenges are also discussed, aiming at highlighting new possible research directions

    Improved Resource Allocation Model for Reducing Interference Among Secondary Users in TV White Space for Broadband Services

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    This research article was published by IEEE Access 2022In recent years, the Television White Space has attracted the interest of many researchers due to its propagation characteristics obtainable between 470MHz and 790MHz spectrum bands. However, aggre- gate interference increase when secondary users in wireless network increase. Aggregate interference on the side of Primary Users has been extensively scrutinized. Therefore, resource allocation (power and spectrum) is crucial when designing the Television White Space network to avoid interferences from Secondary Users to Primary Users and among Secondary Users themselves. This study proposes a resource allocation model that uses joint power and spectrum hybrid Particle Swarm Optimization, Firefly, and Genetic algorithm for reducing the aggregate interference among Secondary Users. The algorithm is integrated with the admission control algorithm so that; there is a possibility of removing some of the Secondary Users in the network whenever the Signal to Noise Ratio threshold for Secondary and Primary Users is not met. We considered an infeasible system whereby all Secondary and Primary Users may not be supported simultaneously. Metrics such as Primary User Signal-to-noise ratio, sum throughput, and secondary user signal-to-noise ratio less than the threshold used to compare the performance of the proposed algorithm and the results show that PSOFAGA with effective link gain ratio admission control has the best performance compared to particle swarm optimization, genetic algorithm, firefly algorithm, and PSOFAGA algorith

    Optimization Algorithms for Large-Scale Real-World Instances of the Frequency Assignment Problem

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    Nowadays, mobile communications are experiencing a strong growth, being more and more indispensable. One of the key issues in the design of mobile networks is the Frequency Assignment Problem (FAP). This problem is crucial at present and will remain important in the foreseeable future. Real world instances of FAP typically involve very large networks, which can only be handled by heuristic methods. In the present work, we are interested in optimizing frequency assignments for problems described in a mathematical formalism that incorporates actual interference information, measured directly on the field, as is done in current GSM networks. To achieve this goal, a range of metaheuristics have been designed, adapted, and rigourously compared on two actual GSM networks modeled according to the latter formalism. In order to generate quickly and reliably high quality solutions, all metaheuristics combine their global search capabilities with a local-search method specially tailored for this domain. The experiments and statistical tests show that in general, all metaheuristics are able to improve upon results published in previous studies, but two of the metaheuristics emerge as the best performers: a population-based algorithm (Scatter Search) and a trajectory based (1+1) Evolutionary Algorithm. Finally, the analysis of the frequency plans obtained offers insight about how the interference cost is reduced in the optimal plans.Publicad

    A Survey on Resource Allocation in Vehicular Networks

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    Vehicular networks, an enabling technology for Intelligent Transportation System (ITS), smart cities, and autonomous driving, can deliver numerous on-board data services, e.g., road-safety, easy navigation, traffic efficiency, comfort driving, infotainment, etc. Providing satisfactory Quality of Service (QoS) in vehicular networks, however, is a challenging task due to a number of limiting factors such as erroneous and congested wireless channels (due to high mobility or uncoordinated channel-access), increasingly fragmented and congested spectrum, hardware imperfections, and anticipated growth of vehicular communication devices. Therefore, it will be critical to allocate and utilize the available wireless network resources in an ultra-efficient manner. In this paper, we present a comprehensive survey on resource allocation schemes for the two dominant vehicular network technologies, e.g. Dedicated Short Range Communications (DSRC) and cellular based vehicular networks. We discuss the challenges and opportunities for resource allocations in modern vehicular networks and outline a number of promising future research directions

    Allocations de ressources dans les réseaux sans fils énergétiquement efficaces.

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    In this thesis, we investigate two techniques used for enhancing the energy orspectral efficiency of the network. In the first part of the thesis, we propose tocombine the network future context prediction capabilities with the well-knownlatency vs. energy efficiency tradeoff. In that sense, we consider a proactivedelay-tolerant scheduling problem. In this problem, the objective consists ofdefining the optimal power strategies of a set of competing users, which minimizesthe individual power consumption, while ensuring a complete requestedtransmission before a given deadline. We first investigate the single user versionof the problem, which serves as a preliminary to the concepts of delay tolerance,proactive scheduling, power control and optimization, used through the first halfof this thesis. We then investigate the extension of the problem to a multiusercontext. The conducted analysis of the multiuser optimization problem leads toa non-cooperative dynamic game, which has an inherent mathematical complexity.In order to address this complexity issue, we propose to exploit the recenttheoretical results from the Mean Field Game theory, in order to transitionto a more tractable game with lower complexity. The numerical simulationsprovided demonstrate that the power strategies returned by the Mean FieldGame closely approach the optimal power strategies when it can be computed(e.g. in constant channels scenarios), and outperform the reference heuristicsin more complex scenarios where the optimal power strategies can not be easilycomputed.In the second half of the thesis, we investigate a dual problem to the previousoptimization problem, namely, we seek to optimize the total spectral efficiencyof the system, in a constant short-term power configuration. To do so, we proposeto exploit the recent advances in interference classification. the conductedanalysis reveals that the system benefits from adapting the interference processingtechniques and spectral efficiencies used by each pair of Access Point (AP) and User Equipment (UE). The performance gains offered by interferenceclassification can also be enhanced by considering two improvements. First, wepropose to define the optimal groups of interferers: the interferers in a samegroup transmit over the same spectral resources and thus interfere, but can processinterference according to interference classification. Second, we define theconcept of ’Virtual Handover’: when interference classification is considered,the optimal Access Point for a user is not necessarily the one providing themaximal SNR. For this reason, defining the AP-UE assignments makes sensewhen interference classification is considered. The optimization process is thenthreefold: we must define the optimal i) interference processing technique andspectral efficiencies used by each AP-UE pair in the system; ii) the matching ofinterferers transmitting over the same spectral resources; and iii) define the optimalAP-UE assignments. Matching and interference classification algorithmsare extensively detailed in this thesis and numerical simulations are also provided,demonstrating the performance gain offered by the threefold optimizationprocedure compared to reference scenarios where interference is either avoidedwith orthogonalization or treated as noise exclusively.Dans le cadre de cette thĂšse, nous nous intĂ©ressons plus particuliĂšrement Ă deux techniques permettant d’amĂ©liorer l’efficacitĂ© Ă©nergĂ©tique ou spectrale desrĂ©seaux sans fil. Dans la premiĂšre partie de cette thĂšse, nous proposons de combinerles capacitĂ©s de prĂ©dictions du contexte futur de transmission au classiqueet connu tradeoff latence - efficacitĂ© Ă©nergĂ©tique, amenant Ă  ce que l’on nommeraun rĂ©seau proactif tolĂ©rant Ă  la latence. L’objectif dans ce genre de problĂšmesconsiste Ă  dĂ©finir des politiques de transmissions optimales pour un ensembled’utilisateur, qui garantissent Ă  chacun de pouvoir accomplir une transmissionavant un certain dĂ©lai, tout en minimisant la puissance totale consommĂ©e auniveau de chaque utilisateur. Nous considĂ©rons dans un premier temps le problĂšmemono-utilisateur, qui permet alors d’introduire les concepts de tolĂ©rance Ă la latence, d’optimisation et de contrÎle de puissance qui sont utilisĂ©s dans lapremiĂšre partie de cette thĂšse. L’extension Ă  un systĂšme multi-utilisateurs estensuite considĂ©rĂ©e. L’analyse rĂ©vĂšle alors que l’optimisation multi-utilisateurpose problĂšme du fait de sa complexitĂ© mathĂ©matique. Mais cette complexitĂ©peut nĂ©anmoins ĂȘtre contournĂ©e grĂące aux rĂ©centes avancĂ©es dans le domainede la thĂ©orie des jeux Ă  champs moyens, thĂ©orie qui permet de transiter d’unjeu multi-utilisateur, vers un jeu Ă  champ moyen, Ă  plus faible complexitĂ©. Lessimulations numĂ©riques dĂ©montrent que les stratĂ©gies de puissance retournĂ©espar l’approche jeu Ă  champ moyen approchent notablement les stratĂ©gies optimaleslorsqu’elles peuvent ĂȘtre calculĂ©es, et dĂ©passent les performances desheuristiques communes, lorsque l’optimum n’est plus calculable, comme c’est lecas lorsque le canal varie au cours du temps.Dans la seconde partie de cettethĂšse, nous investiguons un possible problĂšme dual au problĂšme prĂ©cĂ©dent. PlusspĂ©cifiquement, nous considĂ©rons une approche d’optimisation d’efficacitĂ© spectrale,Ă  configuration de puissance constante. Pour ce faire, nous proposonsalors d’étudier l’impact sur le rĂ©seau des rĂ©centes avancĂ©es en classification d’interfĂ©rence.L’analyse conduite rĂ©vĂšle que le systĂšme peut bĂ©nĂ©ficier d’uneadaptation des traitements d’interfĂ©rence faits Ă  chaque rĂ©cepteur. Ces gainsobservĂ©s peuvent Ă©galement ĂȘtre amĂ©liorĂ©s par deux altĂ©rations de la dĂ©marched’optimisation. La premiĂšre propose de redĂ©finir les groupes d’interfĂ©reurs decellules concurrentes, supposĂ©s transmettre sur les mĂȘmes ressources spectrales.L’objectif Ă©tant alors de former des paires d’interfĂ©reurs “amis”, capables detraiter efficacement leurs interfĂ©rences rĂ©ciproques. La seconde altĂ©ration portele nom de “Virtual Handover” : lorsque la classification d’interfĂ©rence est considĂ©rĂ©e,l’access point offrant le meilleur SNR n’est plus nĂ©cessairement le meilleuraccess point auquel assigner un utilisateur. Pour cette raison, il est donc nĂ©cessairede laisser la possibilitĂ© au systĂšme de pouvoir choisir par lui-mĂȘme la façondont il procĂšde aux assignations des utilisateurs. Le processus d’optimisationse dĂ©compose donc en trois parties : i) DĂ©finir les coalitions d’utilisateurs assignĂ©sĂ  chaque access point ; ii) DĂ©finir les groupes d’interfĂ©reurs transmettantsur chaque ressource spectrale ; et iii) DĂ©finir les stratĂ©gies de transmissionet les traitements d’interfĂ©rences optimaux. L’objectif de l’optimisationest alors de maximiser l’efficacitĂ© spectrale totale du systĂšme aprĂšs traitementde l’interfĂ©rence. Les diffĂ©rents algorithmes utilisĂ©s pour rĂ©soudre, Ă©tape parĂ©tape, l’optimisation globale du systĂšme sont dĂ©taillĂ©s. Enfin, des simulationsnumĂ©riques permettent de mettre en Ă©vidence les gains de performance potentielsofferts par notre dĂ©marche d’optimisation
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