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Abstract: Wireless LANs (WLANs) suffer degrading performance when operating within domestic areas due to multiple reasons such as: multi-path, fading, path loss and user mobility. To overcome this, transmission rate is usually adjusted to a more error-resistant rate. In this paper, we first present a novel rate adaptation algorithm for IEEE 802.11 that can efficiently identify the threshold frame error rate (FER) at which link adjustment is required, based on a simple throughput analysis at the MAC layer. Then, we extend our rate adaptation algorithm to support IEEE 802.11e quality of service (QoS) requirements. When a real-time stream with QoS requirements is admitted, critical constraints such as delay bound and maximum packet drop count are integrated in the selection of the most convenient transmission rate that best respects the flow requirements. Moreover, we use dynamic bandwidth allocation rather than the default transmission opportunities (TXOPs) in a way that best offers a flow the required time for retransmissions due to packet failure based on the variant loss rate present in the channel. We validate our proposed rate adaptation algorithms via simulation results where the efficiency and effectiveness of the algorithm are noticed for both best effort and QoS flows. [Copyright &y& Elsevier]

Abstract: Directional antennas offer numerous benefits for wireless ad hoc networks, such as extended communication range, better spatial reuse, improved capacity and suppressed interference. In this work, we study analytically the benefits of transmission power control on throughput and energy consumption in a uniformly distributed power-aware ad hoc network where nodes are equipped with directional antennas. We construct an interference model for directional antenna based on a honey grid model to calculate the maximum interference. We further derive a directional collision avoidance model and based on the integrated interference/collision model and signal to interference requirements (SIR), we present the maximum end-to-end throughput under the maximum interference. We further investigate the effect of collision on the energy consumption and propose an energy consumption model that utilizes all aspects of energy wastage. [Copyright &y& Elsevier]

The increasing need for reducing greenhouse gas emissions and the drive for green cities have promoted the use of electric vehicles due to their environmental benefits. In fact, countries have set their own targets and are offering incentives for people to purchase EVs as opposed to traditional gasoline-powered cars. Manufacturers have been hastily deploying charging stations to meet the charging requirements of the EVs on the road. This rapid deployment has contributed to the EV ecosystem's lack of proper security measures. raising multiple questions related to the power grid security and vulnerability. In this paper, we offer a complete examination of the EV ecosystem from the vulnerability to the attacks and finally the solutions. We start by examining the existing vulnerabilities in the EV ecosystem that can be exploited to control the EV charging and launch attacks against the power grid. We then discuss the non-linear nature of the EV charging load and simulate multiple attacks that can be launched against the power grid using these EVs. EV loads have high reactive power demand which can have a larger impact on the grid compared to residential loads. We perform simulations on two power grids and demonstrate that while the grid can recover after a 48 MW attack utilizing traditional residential loads, a smaller 30 MW EV load attack can completely destabilize the system. Finally, we suggest several patches for the existing vulnerabilities and discuss two methods aimed at detecting EV attacks. [ABSTRACT FROM AUTHOR]

Electric Vehicles (EVs) and their charging infrastructure have witnessed rapid adoption into the smart grid owing to their ability to reduce the transportation sector's emissions. However, this hasty deployment has left the grid prone to attacks initiated through the charging ecosystem. This paper develops a family of robust dynamic load-altering attacks that manipulate the EV load to destabilize the power grid. The attack strategy is formulated based on feedback control theory and Linear Matrix Inequalities (LMIs) and incorporates mathematical modeling of the power grid uncertainties. The effectiveness of our proposed robust EV attack strategy is demonstrated through extensive simulations of attack scenarios against the New England (NE) 39-bus grid. The results demonstrate that the proposed attacks were able to destabilize the grid frequency inducing a deviation of 1.5 Hz and forcing the generators to trip after compromising as little as 6.6% of the total grid load. We also present a two-tier Deep Learning (DL) attack detection mechanism. We optimize this mechanism to achieve optimal results against dynamic and switching attacks. The proposed mechanism was evaluated against several other models and proved to be superior with an accuracy of 99.9%. • We propose a robust EV Dynamic Attack Design that takes advantage of compromised EVs to cause power grid instability. • The controller design accounts for several uncertainties that can impact the attack success. • We perform extensive time domain simulations to demonstrate the devastating impact of such attacks even in the presence of uncertainties. • The proposed scheme demonstrates its ability to cause generator tripping even with just 6.7% of the total grid load. • We then propose a two-tier detection mechanism that achieved a detection accuracy above 99.9%. [ABSTRACT FROM AUTHOR]

Recent reports indicate that electric vehicle charging stations (EVCSs) are susceptible to remote exploitation through their vulnerable software/cyber components. More importantly, compromised EVCS can be leveraged to perform coordinated oscillatory load attacks against the interconnected power grid, leading to power grid instability, increased operational costs, and power line tripping. In this paper, an edge-based approach for the detection and localization of coordinated oscillatory load attacks initiated by exploited EV charging stations against the power grid is investigated. The edge-based detection relies on the behavioral characteristics of the power grid in the presence of interconnected EVCS while combining cyber and physical layer features to implement deep learning algorithms for the effective detection of oscillatory load attacks at the EVCS. The proposed detection approach was evaluated by building a real-time test bed to synthesize benign and malicious data, which was generated by analyzing real-life EV charging data collected during recent years. The results demonstrate the effectiveness of the implemented approach with the Convolutional Long-Short Term Memory model producing optimal classification accuracy (99.4%). Moreover, this analysis results shed light on the impact of such detection mechanisms towards building resiliency into different levels of the EV charging ecosystem while allowing power grid operators to localize attacks and take further mitigation measures. Specifically, the detection mechanism of oscillatory load attacks is decentralized and created an effective alternative for operator-centric mechanisms to mitigate multi-operator and Man-in-the-Middle (MitM) oscillatory load attacks against the power grid. Additionally, the created test bed is leveraged to evaluate a distributed mitigation technique, which can be deployed on public/private charging stations to average out the impact of oscillatory load attacks while allowing the power system to recover smoothly within 1 second with minimal overhead. Finally, a security metric is createdto evaluate the resiliency of the ecosystem based on its design and architecture. • Creating an edge-based detection mechanism of oscillatory load attacks hosted on Electric Vehicle Charging Stations (EVCSs). • We introduce a distributed mitigation mechanism that is hosted on EVCS that deprives the adversary the ability to synchronize attacks. This was also demonstrated on a co-simulation platform. • Create a security metric that helps evaluate the resiliency of the ecosystem by taking into consideration various components. [ABSTRACT FROM AUTHOR]

Due to the growing threat of climate change, the world's governments have been encouraging the adoption of Electric Vehicles (EVs). As a result, EV numbers have been growing exponentially which will introduce a large EV charging load into the power grid. On this basis, we present a scheme to utilize EVs as a defense mechanism to mitigate Load-Altering (LA) attacks against the grid. The developed scheme relies on robust control theory and Linear Matrix Inequalities (LMIs). Our EV-based defense mechanism is formulated as a feedback controller synthesized using H-2 and H-∞ control techniques to eliminate the impact of unknown LA attacks. The controller synthesis considers the grid topology and the uncertainties of the EV connection to the grid. To demonstrate the effectiveness of the proposed mitigation scheme, it is tested against three types of LA attacks on the New England 39-bus grid. We test our mitigation scheme against 800 MW static, switching, and dynamic attacks in the presence of multiple sources of uncertainty that can affect the EV load during deployment. The results demonstrate how the grid remains stable under the LA attacks that would otherwise lead to serious instabilities. • We propose a robust controller that utilizes EV active and reactive charging load to eliminate the impact of persisting load altering attacks. • The controller design accounts for several real-life uncertainties including, communication delay, uncertain EV load, EV load clustering, etc. • Our extensive simulations demonstrate how the devastating impact of the 3 types of LA attacks is eliminated completely and instantaneously. • The proposed attack mitigation scheme also successfully eliminates the impact of contingencies on the power grid such as line tripping or generator relay tripping as these events resemble the behavior of a static attack. • The stability of the controller was examined, and it was demonstrated that the controller's performance remains stable under a wide operation margin. [ABSTRACT FROM AUTHOR]