An Economic Framework For Resource Management And Pricing In Wireless Networks With Competitive Service Providers

A paradigm shift from static spectrum allocation to dynamic spectrum access (DSA) is becoming a reality due to the recent advances in cognitive radio, wide band spectrum sensing, and network aware real--time spectrum access. It is believed that DSA will allow wireless service providers (WSPs) the opportunity to dynamically access spectrum bands as and when they need it. Moreover, due to the presence of multiple WSPs in a region, it is anticipated that dynamic service pricing would be offered that will allow the end-users to move from long-term service contracts to more flexible short-term service models. In this research, we develop a unified economic framework to analyze the trading system comprising two components: i) spectrum owner--WSPs interactions with regard to dynamic spectrum allocation, and ii) WSP--end-users interactions with regard to dynamic service pricing. For spectrum owner--WSPs interaction, we investigate various auction mechanisms for finding bidding strategies of WSPs and revenue generated by the spectrum owner. We show that sequential bidding provides better result than the concurrent bidding when WSPs are constrained to at most single unit allocation. On the other hand, when the bidders request for multiple units, (i.e., they are not restricted by allocation constraints) synchronous auction mechanism proves to be beneficial than asynchronous auctions. In this regard, we propose a winner determination sealed-bid knapsack auction mechanism that dynamically allocates spectrum to the WSPs based on their bids. As far as dynamic service pricing is concerned, we use game theory to capture the conflict of interest between WSPs and end--users, both of whom try to maximize their respective net utilities. We deviate from the traditional per--service static pricing towards a more dynamic model where the WSPs might change the price of a service almost on a session by session basis. Users, on the other hand, have the freedom to choose their WSP based on the price offered. It is found that in such a greedy and non-cooperative behavioral game model, it is in the best interest of the WSPs to adhere to a price threshold which is a consequence of a price (Nash) equilibrium. We conducted extensive simulation experiments, the results of which show that the proposed auction model entices WSPs to participate in the auction, makes optimal use of the common spectrum pool, and avoids collusion among WSPs. We also demonstrate how pricing can be used as an effective tool for providing incentives to the WSPs to upgrade their network resources and offer better services

Digital Twins for Moving Target Defense Validation in AC Microgrids

Cyber-physical microgrids are vulnerable to stealth attacks that can degrade their stability and operability by performing low-magnitude manipulations in a coordinated manner. This paper formulates the interactions between CSAs and microgrid defenders as a non-cooperative, zero-sum game. Additionally, it presents a hybrid Moving Target Defense (MTD) strategy for distributed microgrids that can dynamically alter local control gains to achieve resiliency against Coordinated Stealth Attacks (CSAs). The proposed strategy reduces the success probability of attack(s) by making system dynamics less predictable. The framework also identifies and removes malicious injections by modifying secondary control weights assigned to them. The manipulated signals are reconstructed using an Artificial Neural Network (ANN)-based Digital Twin (DT) to preserve stability. To guarantee additional immunity against instability arising from gain alterations, MTD decisions are also validated (via utility and best response computations) using the DT before actual implementation. The DT is also used to find the minimum perturbation that defenders must achieve to invalidate an attacker's knowledge effectively.Comment: IEEE Energy Conversion Congress and Expo (ECCE) 202

Improvise, Adapt, Overcome: Dynamic Resiliency Against Unknown Attack Vectors in Microgrid Cybersecurity Games

Cyber-physical microgrids are vulnerable to rootkit attacks that manipulate system dynamics to create instabilities in the network. Rootkits tend to hide their access level within microgrid system components to launch sudden attacks that prey on the slow response time of defenders to manipulate system trajectory. This problem can be formulated as a multi-stage, non-cooperative, zero-sum game with the attacker and the defender modeled as opposing players. To solve the game, this paper proposes a deep reinforcement learning-based strategy that dynamically identifies rootkit access levels and isolates incoming manipulations by incorporating changes in the defense plan. A major advantage of the proposed strategy is its ability to establish resiliency without altering the physical transmission/distribution network topology, thereby diminishing potential instability issues. The paper also presents several simulation results and case studies to demonstrate the operating mechanism and robustness of the proposed strategy

Lost at Sea: Assessment and Evaluation of Rootkit Attacks on Shipboard Microgrids

Increased dependence of the maritime industry on information and communication networks has made shipboard power systems vulnerable to stealthy cyber-attacks. One such attack variant, called rootkit, can leverage system knowledge to hide its presence and allow remotely located malware handlers to gain complete control of infected subsystems. This paper presents a comprehensive evaluation of the threat landscape imposed by such attack variants on Medium Voltage DC (MVDC) shipboard microgrids, including a discussion of their impact on the overall maritime sector in general, and provides several simulation results to demonstrate the same. It also analyzes and presents the actions of possible defense mechanisms, with specific emphasis on evasion, deception, and detection frameworks, that will help ship operators and maritime cybersecurity professionals protect their systems from such attacks.Comment: 2023 IEEE Electric Ship Technologies Symposium (ESTS

Competitive Spectrum Trading in Dynamic Spectrum Access Markets: A Price War

Abstract—The concept of dynamic spectrum access (DSA) enables the licensed spectrum to be traded in an open market where the unlicensed users can freely buy and use the available licensed spectrum bands. However, like in the other traditional commodity markets, spectrum trading is inevitably accompanied by various competitions and challenges. In this paper, we study an important business competition activity – price war in the DSA market. A non-cooperative pricing game is formulated to model the contention among multiple wireless spectrum providers for higher market share and revenues. We calculate the Pareto optimal pricing strategies for all providers and analyze the motivations behind the price war. The potential responses to the price war are in-depth discussed. Numerical results demonstrate the efficiency of the Pareto optimal strategy for the game and the impact of the price war to all participants. I

Distributed Power Control In Sensor Networks: A Game Theoretic Approach

In wireless sensor networks, where energy of the sensor nodes are finite, power control is an important issue to consider. In this paper, we present a game-theoretic approach to solve the power control problem in CDMA based distributed sensor networks. A non-cooperative game is formulated and the existence of Nash equilibrium is studied for the sensor nodes operating under incomplete information. With the help of this equilibrium, we devise a distributed algorithm for optimal power control and prove that the system is power stable if the nodes comply with certain transmission thresholds. We show that even in the distributed non-cooperative scenario, it is in the best interest of the nodes to remain within these thresholds. The power level at which a node should transmit, to maximize its utility, is also evaluated. Numerical results prove that with the proposed algorithm, the sensor nodes are able to achieve best possible payoff by consuming less power, resulting in extended network lifetime. © Springer-Verlag Berlin Heidelberg 2004

Designing Auction Mechanisms For Dynamic Spectrum Access

With the increasing demands for radio spectrum, techniques are being explored that would allow dynamic access of spectrum bands that are under-utilized. In this regard, a new paradigm called dynamic spectrum access is being investigated where wireless service providers (WSPs) would dynamically seek more spectrum from the under-utilized licensed bands when and where they need without interfering with the primary users. Currently, there is little understanding on how such a dynamic allocation will operate so as to make the system feasible under economic terms. In this paper, we consider the dynamic spectrum allocation process where multiple WSPs (bidders) compete to acquire necessary spectrum band from a common pool of spectrum. We use auction theory to analyze the allocation process when the demand from WSPs exceeds the available spectrum. We investigate various auction mechanisms under different spectrum allocation constraints to find WSPs\u27 bidding strategies and revenue generated by spectrum owner. We show that sequential bidding of bands provides better result than the concurrent bidding when WSPs are constrained to at most single unit allocation. On the other hand, when the bidders request for multiple units, (i.e., they are not restricted by allocation constraints) synchronous auction mechanism proves to be beneficial than asynchronous auctions. © 2008 Springer Science+Business Media, LLC

Synchronous And Asynchronous Auction Models For Dynamic Spectrum Access

Recently, there is an urge to allocate chunks of the spectrum to the wireless service providers on a more dynamic basis rather than the current practice of static allocation. This shift in paradigm is a result of many studies that indicate the improper utilization of the spectrum by the service providers due to the static spectrum assignment. Also, the use of the spectrum has been found to be space and time invariant. In this paper, we investigate the dynamic spectrum allocation policy for optimal use of the spectrum band. We propose a dynamic spectrum assignment strategy based on auction theory that captures the conflict of interest between wireless service providers and spectrum owner, both of whom try to maximize their respective benefits. We compare two different allocation strategies - synchronous and asynchronous. It is demonstrated that synchronous strategy outperforms the asynchronous strategy. Through simulation results, we show how the optimal usage of spectrum band is achieved along with the maximized revenue for spectrum owner and higher probability of winning spectrum for the service providers. © Springer-Verlag Berlin Heidelberg 2006