Fair scheduling in cellular systems in the presence of noncooperative mobiles

We consider the problem of 'fair' scheduling the resources to one of the many mobile stations by a centrally controlled base station (BS). The BS is the only entity taking decisions in this framework based on truthful information from the mobiles on their radio channel. We study the well-known family of parametric -fair scheduling problems from a gametheoretic perspective in which some of the mobiles may be noncooperative. We first show that if the BS is unaware of the noncooperative behavior from the mobiles, the noncooperative mobiles become successful in snatching the resources from the other cooperative mobiles, resulting in unfair allocations. If the BS is aware of the noncooperative mobiles, a new game arises with BS as an additional player. It can then do better by neglecting the signals from the noncooperative mobiles. The BS, however, becomes successful in eliciting the truthful signals from the mobiles only when it uses additional information (signal statistics). This new policy along with the truthful signals from mobiles forms a Nash Equilibrium (NE) which we call a Truth Revealing Equilibrium. Finally, we propose new iterative algorithms to implement fair scheduling policies that robustify the otherwise non-robust (in presence of noncooperation) fair scheduling algorithms

Crawford-Sobel meet Lloyd-Max on the grid

The main contribution of this work is twofold. First, we apply, for the first time, a framework borrowed from economics to a problem in the smart grid namely, the design of signaling schemes between a consumer and an electricity aggregator when these have non-aligned objectives. The consumer's objective is to meet its need in terms of power and send a request (a message) to the aggregator which does not correspond, in general, to its actual need. The aggregator, which receives this request, not only wants to satisfy it but also wants to manage the cost induced by the residential electricity distribution network. Second, we establish connections between the exploited framework and the quantization problem. Although the model assumed for the payoff functions for the consumer and aggregator is quite simple, it allows one to extract insights of practical interest from the analysis conducted. This allows us to establish a direct connection with quantization, and more importantly, to open a much more general challenge for source and channel coding.Comment: ICASSP 2014, 5 page

An Energy-Efficient Power Allocation Game with Selfish Channel State Reporting in Cellular Networks

International audienceEnergy-efficient ressource allocation is a powerful approach to reduce the operation costs and environmental footprint of cellular networks. With energy-efficient resource allocation, mobile users and base station have different objectives. While the base station strives for an energy-efficient operation of the complete cell, each user aims to maximize its own data rate. To obtain this individual benefit, users may selfishly adjust their \ac{CSI} reports, reducing the cell's energy efficiency. To analyze this conflict of interest, we formalize energy-efficient power allocation as a utility maximization problem and present a simple algorithm that performs close to the optimum. By formulating selfish CSI reporting as a game, we prove the existence of an unique equilibrium and characterize energy efficiency with true and selfish CSI in closed form. Our numerical results show that, surprisingly, energy-efficient power allocation in small cells is more robust against selfish CSI than cells with large transmit powers. This and further design rules show that our paper provides valuable theoretical insight to energy-efficient networks when CSI reports cannot be trusted

Reliable Downlink Scheduling for Wireless Networks with Real-Time and Non-Real Time Clients

In this thesis, we studied the problem of designing a down link scheduling policy to serve multiple types of clients from a base station in a time-varying wireless network. An ideal scheduling policy is fair among the clients, provides reliability to the clients, achieves high system throughput and prevents strategic clients from choosing incorrect means. The existing scheduling policies fail to achieve one or more of these features. The Proportional Fair scheduling policy for example, fails to provide reliability to the real time clients, while Round Robin policy provides reliability to the clients but fails to achieve high system throughput in a time-varying wireless network. Apart from these policies, there are scheduling policies which prioritize clients based on their delay requirements. Here, a client with lower priority may choose incorrect means like claiming false types of flows to obtain a better performance. A non-real time client may pretend to be a real time client if doing so, which might aid it to achieve better performance in terms of average throughput. We proposed a new scheduling policy that is not only proportionally fair but also provides reliability to the mixture of real time and non-real time clients over a shared wireless channel. Our proposed policy aims to serve clients with different service requirements and provides best service to the clients which furnish true information about their service requirements; the client claiming false service requirements is penalized with the reduced performance. We theoretically demonstrate the effectiveness of the algorithm by considering uniform distribution of service rates of all the clients. We then provide extensive simulation results of our scheduling policy under the fast fading Rayleigh model to show that this policy can be easily extended in wireless networks. We also show that our policy outperforms existing policies in providing better reliability to the clients and unlike other common policies, our policy degrades the performance of a client that chooses incorrect means

Game Theory for Multi-Access Edge Computing:Survey, Use Cases, and Future Trends

Game theory (GT) has been used with significant success to formulate, and either design or optimize, the operation of many representative communications and networking scenarios. The games in these scenarios involve, as usual, diverse players with conflicting goals. This paper primarily surveys the literature that has applied theoretical games to wireless networks, emphasizing use cases of upcoming multiaccess edge computing (MEC). MEC is relatively new and offers cloud services at the network periphery, aiming to reduce service latency backhaul load, and enhance relevant operational aspects such as quality of experience or security. Our presentation of GT is focused on the major challenges imposed by MEC services over the wireless resources. The survey is divided into classical and evolutionary games. Then, our discussion proceeds to more specific aspects which have a considerable impact on the game's usefulness, namely, rational versus evolving strategies, cooperation among players, available game information, the way the game is played (single turn, repeated), the game's model evaluation, and how the model results can be applied for both optimizing resource-constrained resources and balancing diverse tradeoffs in real edge networking scenarios. Finally, we reflect on lessons learned, highlighting future trends and research directions for applying theoretical model games in upcoming MEC services, considering both network design issues and usage scenarios

Contributions to Wireless multi-hop networks : Quality of Services and Security concerns

Ce document résume mes travaux de recherche conduits au cours de ces 6 dernières années. Le principal sujet de recherche de mes contributions est la conception et l’évaluation des solutions pour les réseaux sans fil multi-sauts en particulier les réseaux mobiles adhoc (MANETs), les réseaux véhiculaires ad hoc (VANETs), et les réseaux de capteurs sans fil (WSNs). La question clé de mes travaux de recherche est la suivante : « comment assurer un transport des données e cace en termes de qualité de services (QoS), de ressources énergétiques, et de sécurité dans les réseaux sans fil multi-sauts? » Pour répondre à cette question, j’ai travaillé en particulier sur les couches MAC et réseau et utilisé une approche inter-couches.Les réseaux sans fil multi-sauts présentent plusieurs problèmes liés à la gestion des ressources et au transport des données capable de supporter un grand nombre de nœuds, et d’assurer un haut niveau de qualité de service et de sécurité.Dans les réseaux MANETs, l’absence d’infrastructure ne permet pas d’utiliser l’approche centralisée pour gérer le partage des ressources, comme l’accès au canal.Contrairement au WLAN (réseau sans fil avec infrastructure), dans les réseaux Ad hoc les nœuds voisins deviennent concurrents et il est di cile d’assurer l’équité et l’optimisation du débit. La norme IEEE802.11 ne prend pas en compte l’équité entre les nœuds dans le contexte des MANETs. Bien que cette norme propose di érents niveaux de transmission, elle ne précise pas comment allouer ces débits de manière e cace. En outre, les MANETs sont basés sur le concept de la coopération entre les nœuds pour former et gérer un réseau. Le manque de coopération entre les nœuds signifie l’absence de tout le réseau. C’est pourquoi, il est primordial de trouver des solutions pour les nœuds non-coopératifs ou égoïstes. Enfin, la communication sans fil multi-sauts peut participer à l’augmentation de la couverture radio. Les nœuds de bordure doivent coopérer pour transmettre les paquets des nœuds voisins qui se trouvent en dehors de la zone de couverture de la station de base.Dans les réseaux VANETs, la dissémination des données pour les applications de sureté est un vrai défi. Pour assurer une distribution rapide et globale des informations, la méthode de transmission utilisée est la di usion. Cette méthode présente plusieurs inconvénients : perte massive des données due aux collisions, absence de confirmation de réception des paquets, non maîtrise du délai de transmission, et redondance de l’information. De plus, les applications de sureté transmettent des informations critiques, dont la fiabilité et l’authenticité doivent être assurées.Dans les réseaux WSNs, la limitation des ressources (bande passante, mémoire, énergie, et capacité de calcul), ainsi que le lien sans fil et la mobilité rendent la conception d’un protocole de communication e cace di cile. Certaines applications nécessitent un taux important de ressources (débit, énergie, etc) ainsi que des services de sécurité, comme la confidentialité et l’intégrité des données et l’authentification mutuelle. Ces paramètres sont opposés et leur conciliation est un véritable défi. De plus, pour transmettre de l’information, certaines applications ont besoin de connaître la position des nœuds dans le réseau. Les techniques de localisation sou rent d’un manque de précision en particulier dans un environnement fermé (indoor), et ne permettent pas de localiser les nœuds dans un intervalle de temps limité. Enfin, la localisation des nœuds est nécessaire pour assurer le suivi d’objet communicant ou non. Le suivi d’objet est un processus gourmand en énergie, et requiert de la précision.Pour répondre à ces défis, nous avons proposé et évalué des solutions, présentées de la manière suivante : l’ensemble des contributions dédiées aux réseaux MANETs est présenté dans le deuxième chapitre. Le troisième chapitre décrit les solutions apportées dans le cadre des réseaux VANETs. Enfin, les contributions liées aux réseaux WSNs sont présentées dans le quatrième chapitre

Cognitive radio systems in LTE networks

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London.The most important fact in the mobile industry at the moment is that demand for wireless services will continue to expand in the coming years. Therefore, it is vital to find more spectrums through cognitive radios for the growing numbers of services and users. However, the spectrum reallocations, enhanced receivers, shared use, or secondary markets-will not likely, by themselves or in combination, meet the real exponential increases in demand for wireless resources. Network operators will also need to re-examine network architecture, and consider integrating the fibre and wireless networks to address this issue. This thesis involves driving fibre deeper into cognitive networks, deploying microcells connected through fibre infrastructure to the backbone LTE networks, and developing the algorithms for diverting calls between the wireless and fibre systems, introducing new coexistence models, and mobility management. This research addresses the network deployment scenarios to a microcell-aided cognitive network, specifically slicing the spectrum spatially and providing reliable coverage at either tier. The goal of this research is to propose new method of decentralized-to-distributed management techniques that overcomes the spectrum unavailability barrier overhead in ongoing and future deployments of multi-tiered cognitive network architectures. Such adjustments will propose new opportunities in cognitive radio-to-fibre systematic investment strategies. Specific contributions include: 1) Identifying the radio access technologies and radio over fibre solution for cognitive network infrastructure to increase the uplink capacity analysis in two-tier networks. 2) Coexistence of macro and microcells are studied to propose a roadmap for optimising the deployment of cognitive microcells inside LTE macrocells in the case of considering radio over fibre access systems. 3) New method for roaming mobiles moving between microcells and macrocell coverage areas is proposed for managing spectrum handover, operator database, authentication and accounting by introducing the channel assigning agent entity. The ultimate goal is to reduce unnecessary channel adaptation

Quantifying Potential Energy Efficiency Gain in Green Cellular Wireless Networks

Conventional cellular wireless networks were designed with the purpose of providing high throughput for the user and high capacity for the service provider, without any provisions of energy efficiency. As a result, these networks have an enormous Carbon footprint. In this paper, we describe the sources of the inefficiencies in such networks. First we present results of the studies on how much Carbon footprint such networks generate. We also discuss how much more mobile traffic is expected to increase so that this Carbon footprint will even increase tremendously more. We then discuss specific sources of inefficiency and potential sources of improvement at the physical layer as well as at higher layers of the communication protocol hierarchy. In particular, considering that most of the energy inefficiency in cellular wireless networks is at the base stations, we discuss multi-tier networks and point to the potential of exploiting mobility patterns in order to use base station energy judiciously. We then investigate potential methods to reduce this inefficiency and quantify their individual contributions. By a consideration of the combination of all potential gains, we conclude that an improvement in energy consumption in cellular wireless networks by two orders of magnitude, or even more, is possible.Comment: arXiv admin note: text overlap with arXiv:1210.843