A Survey on Dynamic Spectrum Access Techniques in Cognitive Radio Networks

The idea of Cognitive Radio (CR) is to share the spectrum between a user called primary, and a user called secondary. Dynamic Spectrum Access (DSA) is a new spectrum sharing paradigm in cognitive radio that allows secondary users to access the abundant spectrum holes in the licensed spectrum bands. DSA is an auspicious technology to alleviate the spectrum scarcity problem and increase spectrum utilization. While DSA has attracted many research efforts recently, in this paper, a survey of spectrum access techniques using cooperation and competition to solve the problem of spectrum allocation in cognitive radio networks is presented

Auction-based Charging Scheduling with Deep Learning Framework for Multi-Drone Networks

State-of-the-art drone technologies have severe flight time limitations due to weight constraints, which inevitably lead to a relatively small amount of available energy. Therefore, frequent battery replacement or recharging is necessary in applications such as delivery, exploration, or support to the wireless infrastructure. Mobile charging stations (i.e., mobile stations with charging equipment) for outdoor ad-hoc battery charging is one of the feasible solutions to address this issue. However, the ability of these platforms to charge the drones is limited in terms of the number and charging time. This paper designs an auction-based mechanism to control the charging schedule in multi-drone setting. In this paper, charging time slots are auctioned, and their assignment is determined by a bidding process. The main challenge in developing this framework is the lack of prior knowledge on the distribution of the number of drones participating in the auction. Based on optimal second-price-auction, the proposed formulation, then, relies on deep learning algorithms to learn such distribution online. Numerical results from extensive simulations show that the proposed deep learning-based approach provides effective battery charging control in multi-drone scenarios.Comment: 14 pages, 19 figures, IEEE Transactions on Vehicular Technology ( Volume: 68 , Issue: 5 , May 2019

Channel assembling and resource allocation in multichannel spectrum sharing wireless networks

Submitted in fulfilment of the academic requirements for the degree of Doctor of Philosophy (Ph.D.) in Engineering, in the School of Electrical and Information Engineering, Faculty of Engineering and the Built Environment, at the University of the Witwatersrand, Johannesburg, South Africa, 2017The continuous evolution of wireless communications technologies has increasingly imposed a burden on the use of radio spectrum. Due to the proliferation of new wireless networks applications and services, the radio spectrum is getting saturated and becoming a limited resource. To a large extent, spectrum scarcity may be a result of deficient spectrum allocation and management policies, rather than of the physical shortage of radio frequencies. The conventional static spectrum allocation has been found to be ineffective, leading to overcrowding and inefficient use. Cognitive radio (CR) has therefore emerged as an enabling technology that facilitates dynamic spectrum access (DSA), with a great potential to address the issue of spectrum scarcity and inefficient use. However, provisioning of reliable and robust communication with seamless operation in cognitive radio networks (CRNs) is a challenging task. The underlying challenges include development of non-intrusive dynamic resource allocation (DRA) and optimization techniques. The main focus of this thesis is development of adaptive channel assembling (ChA) and DRA schemes, with the aim to maximize performance of secondary user (SU) nodes in CRNs, without degrading performance of primary user (PU) nodes in a primary network (PN). The key objectives are therefore four-fold. Firstly, to optimize ChA and DRA schemes in overlay CRNs. Secondly, to develop analytical models for quantifying performance of ChA schemes over fading channels in overlay CRNs. Thirdly, to extend the overlay ChA schemes into hybrid overlay and underlay architectures, subject to power control and interference mitigation; and finally, to extend the adaptive ChA and DRA schemes for multiuser multichannel access CRNs. Performance analysis and evaluation of the developed ChA and DRA is presented, mainly through extensive simulations and analytical models. Further, the cross validation has been performed between simulations and analytical results to confirm the accuracy and preciseness of the novel analytical models developed in this thesis. In general, the presented results demonstrate improved performance of SU nodes in terms of capacity, collision probability, outage probability and forced termination probability when employing the adaptive ChA and DRA in CRNs.CK201

Applications of Game Theory and Microeconomics in Cognitive Radio and Femtocell Networks

Cognitive radio networks have recently been proposed as a promising approach to overcome the serious problem of spectrum scarcity. Other emerging concept for innovative spectrum utilization is femtocells. Femtocells are low-power and short-range wireless access points installed by the end-user in residential or enterprise environments. A common feature of cognitive radio and femtocells is their two-tier nature involving primary and secondary users (PUs, SUs). While this new paradigm enables innovative alternatives to conventional spectrum management and utilization, it also brings its own technical challenges. A main challenge in cognitive radio is the design of efficient resource (spectrum) trading methods. Game and microeconomics theories provide tools for studying the strategic interactions through rationality and economic benefits between PUs and SUs for effective resource allocation. In this thesis, we investigate some efficient game theoretic and microeconomic approaches to address spectrum trading in cognitive networks. We propose two auction frameworks for shared and exclusive use models. In the first auction mechanism, we consider the shared used model in cognitive radio networks and design a spectrum trading method to maximize the total satisfaction of the SUs and revenue of the Wireless Service Provider (WSP). In the second auction mechanism, we investigate spectrum trading via auction approach for exclusive usage spectrum access model in cognitive radio networks. We consider a realistic valuation function and propose an efficient concurrent Vickrey-Clarke-Grove (VCG) mechanism for non-identical channel allocation among r-minded bidders in two different cases. The realization of cognitive radio networks in practice requires the development of effective spectrum sensing methods. A fundamental question is how much time to allocate for sensing purposes. In the literature on cognitive radio, it is commonly assumed that fixed time durations are assigned for spectrum sensing and data transmission. It is however possible to improve the network performance by finding the best tradeoff between sensing time and throughput. In this thesis, we derive an expression for the total average throughput of the SUs over time-varying fading channels. Then we maximize the total average throughput in terms of sensing time and the number of SUs assigned to cooperatively sense each channel. For practical implementation, we propose a dynamical programming algorithm for joint optimization of sensing time and the number of cooperating SUs for sensing purpose. Simulation results demonstrate that significant improvement in the throughput of SUs is achieved in the case of joint optimization. In the last part of the thesis, we further address the challenge of pricing in oligopoly market for open access femtocell networks. We propose dynamic pricing schemes based on microeconomic and game theoretic approaches such as market equilibrium, Bertrand game, multiple-leader-multiple-follower Stackelberg game. Based on our approaches, the per unit price of spectrum can be determined dynamically and mobile service providers can gain more revenue than fixed pricing scheme. Our proposed methods also provide residential customers more incentives and satisfaction to participate in open access model.1 yea

Auction based Spectrum Management of Cognitive Radio Networks

感知無線電技術被認為是改善整體頻譜使用效率的一個有效的解決方法，特別是當主要無線電網路有相對較低的頻譜使用率。然而，要實現感知無線電概念，提供主要無線電網路使用者足夠的動機和提供服務提供者額外的收益是非常重要的，如此一來感知無線電行動用戶才有可能偶然地使用主要無線電網路的頻譜，這帶給了頻譜管理一個新的挑戰，在這篇論文裡，我們考慮一個主要無線電網路，它包含一個主要系統基地台和好幾個主要系統行動用戶，因此我們可以建構出一感知無線電網路，它包含一個主要無線電網路和好幾個感知無線電行動用戶。我們提出了一個以彼特力競價為架構的頻譜管理策略，使的感知無線電行動用戶可以去競爭主要無線電網路的頻譜，而主要系統用戶可以有折扣去使用頻譜，而且來自感知無線電行動用戶的干擾可以被限制在可以忍受的範圍裡，一旦被感知無線電行動用戶干擾，還可以受到補償來，藉由這些來提供主要系統行動用戶動機，使的感知無線電行動用戶可以使用主要無線電的頻譜。感知無線電行動用戶旦被允許可以使用頻譜，他們可以使用一段特定期間而不必做任何的頻譜轉移。因此，除了提供動機給主要系統用戶，整體的頻譜使用率、服務提供者的收益，感知無線電行動用戶可以使用頻譜的機會都可以因此而提升，使的所有相關的團體能達到共贏的局面。Cognitive radio (CR) technology is considered as an effective solution to enhance overall spectrum efficiency, while primary radio network (PRN) typically havingelatively low spectrum utilization. However, to realize CR concept, it is essential to provide enough incentives to PRN and extra profit to the service provider such thatognitive radio mobile stations (CR-MSs) may utilize PRN spectrum bands accordingly, which provides a new challenge for spectrum management. In this paper, we consider aRN consisting of a primary system base station (PS-BS) and multiple primary system mobile stations (PS-MSs), and we therefore construct a cognitive radio network (CRN) consisting of a PRN with multiple CR-MSs. We propose a spectrum manage policy framework by Vickrey auction such that CR-MSs can compete to utilize the PRN spectrum bands available for opportunistic transmission of CR-MSs. PRN users are granted incentives at a discounting factor to access spectrum bands and being compensated for possible operating interference from CR-MSs, while the interference is constrained under a tolerance level without losing satisfaction for PS-MSs. Once CR-MSs are granted the spectrum bands, they can utilize the spectrum bands for certain duration without any spectrum handoff. Consequently, in addition to incentives to the PRN, the overall spectrum utilization, the profit of the service provider, and the opportunity of accessing spectrum for the CR-MSs are enhanced to achieve co-win situation for every involved party in cognitive radio networks.口試委員會審定書 #謝 i文摘要 iiBSTRACT iiiONTENTS ivIST OF FIGURES viIST OF TABLES ixhapter 1 Introduction 1.1 Cognitive Radio Networks 1.2 Spectrum Management Challenge 4.3 The Overview of Proposed Spectrum Management Policy 5.4 Organization 7hapter 2 Preliminaries 8.1 Spectrum Pricing via Game Theory 10.2 Spectrum Pricing via Auction Theory 13hapter 3 System Model 15.1 Network Topology 15.2 Superframe Structure 16.3 Traffic Model 17.3.1 Traffic Model for PS-MSs 17.3.2 Traffic Model for CR-MSs 17.3 Compensating Mechanism 18.4 Pricing Model 19.4.1 Pricing Model for PS-MSs 19.4.2 Pricing Model for CR-MSs 20hapter 4 Spectrum Management Policy and Formulation 23.1 Spectrum Management Policy (SMP) 23.2 The Formulation 25.2.1 The Expected Profit of the Service Provider per Superframe Dutation 26.2.2 The Average Spectrum Utilization per Superframe Duration 31.3 Optimal SMP Problem 32hapter 5 Performance Evaluation 34.1 Simulation Parameter Setup 34.2 Performance Enhancement for Four Parties 37.2.1 Performance v.s. Kl (the number of spectrum bands allocated to CR-MSs) 37.2.2 Performance v.s. D (the number of data Frames in a superframe ) 40.2.3 Performance v.s. α (discounting factor for PS-MSs to utilize spectrum bands) 42.2.4 Performance v.s. NC (the number of CR-MSs competing to utilize spectrum bands in one control frame) 43hapter 6 Conclusions and Future Works 53.1 Conclusions 53.2 Future Works 54ibliography 5