Suman Bhunia

CR-Honeynet: A Learning & Decoy Based Sustenance Mechanism against Jamming Attack in CRN

Cognitive Radio Network (CRN) enables secondary users to borrow unused spectrum from the proprietary users in a dynamic and opportunistic manner. However, dynamic and open access nature of available spectrum brings a serious challenge of sustenance amongst CRNs which makes them vulnerable to various spectrum etiquette attacks. Jamming-based denial of service (DoS) attack poses serious threats to legitimate communications and packet delivery. A rational attacker targets certain transmission characteristics to find the highest impacting communication of CRN and causes maximum disruption. In this paper, inspired by the honey pot concept in cyber crime, we propose a honey net based defense mechanism, which aims to deter the attacker from jamming legitimate communications. The honey net passively learns the attackers strategy from the past history of attacks and actively adapts pre-emptive decoy mechanisms to prevent attacks on legitimate communications. Simulation results show that the with help of honey net mechanism, CRN successfully avoids jamming attacks and thereby improves system performance in terms of packet delivery ratio.

Performance of Adaptive Beam Nulling in Multihop Ad-Hoc Networks under Jamming

In a multihop ad hoc network, end-to-end data transmissions traverse through multiple inter-node wireless links. A jammer can disrupt the entire data transfer of a network by intentionally interfering with links between a subset of nodes. The impact of such attacks is escalated when the jammer is moving. While the majority of current ad hoc protocols consider omnidirectional transmission and reception, adaptive antennas can be utilized for spatial filtering of the jamming signal. This paper investigates the performance of employing adaptive beam nulling as a mitigation technique against jamming attacks in multihop ad hoc networks. Considering a moving jammer, the survivability of links and connectivity in such networks are studied by simulating various node distributions and different mobility patterns of the attacker. In addition, the impact of errors in estimation of direction of arrival and beamforming on the overall network performance are also examined. The results indicate a significant improvement in retaining connectivity under jamming when adaptive beam nulling is applied.

Performance analysis of CR-honeynet to prevent jamming attack through stochastic modeling

Abstract Cognitive Radio Network (CRN) has to stall its packet transmission periodically to sense the spectrum for Primary User’s (PU’s) transmission. The limited and dynamically available spectrum and fixed periodic schedule of transmission interruption makes it harder to model the performance of a CRNs. Again, an open and dynamic spectrum access model brings forth a serious challenge of sustenance among the CRN and makes them more susceptible to jamming-based denial of service (DoS) attacks. Inspired by honeypot in the network security, we propose a honeynet based defense mechanism called CR-honeynet. CR-honeynet aims to avoid attacks on legitimate communications by dedicating a Secondary User (SU) as a honeynode, to deter the attacker from attacking legitimate SUs and attack the honeynode instead. Dedicating an SU as honeynode, on account of its permanent idleness, is wasteful of an entire node as a resource. We seek to resolve the dilemma by dynamically selecting the honeynode for each transmission period. The contribution of the current paper is two-fold. Initially, we develop the first comprehensive queuing model for CRNs, which pose unique modeling challenges, due to their fixed periodic sensing and transmission cycles. In the second step, we introduce a series of strategies for honeynode selection to combat these attacks while keeping the CRN’s performance optimal for different traffic scenarios. We build a simulation of a CRN under jamming attack and analyze its performance with different honeynode selection strategies. We find that the predictions, of our mathematical model, track closely with the results of our simulation experiments.

A game-theoretic and stochastic survivability mechanism against induced attacks in Cognitive Radio Networks ☆

Abstract Cognitive Radio Networks (CRNs) are envisioned to provide a solution to the scarcity of the available frequency spectrum. It allows unlicensed secondary users (SUs) to use spectrum bands that are not occupied by licensed primary users (PUs) in an opportunistic manner. This dynamic manner of spectrum access gives rise to vulnerabilities that are unique to CRNs. In the battle over the available spectrum, SUs do not have any means of identifying whether disruption sensed on a band is intentional or unintentional. This problem is further intensified in the case of heterogeneous spectrum, where different bands provide different utilities. A smart malicious agent can use this vulnerability to temporarily disrupt transmissions on certain bands and induce their unavailability on SUs. The motivation for such disruption-induced attacks can be either monopolism, i.e. to capture as much spectrum as possible and make other SUs starve, or denial of service by intentional disruption of other SUs’ communications. This paper proposes an adaptive strategy for robust dynamic spectrum access in the event of induced attacks. Assuming rational players, and considering the notion of channel utility, the optimal strategy is established by modeling such scenarios as zero-sum games that lead to Nash equilibrium. Thereafter, the case of non-stationary channel utilities is investigated, where utilities are subject to abrupt changes due to fluctuations in channel characteristics, as well as arrival and departure of PUs. Through concurrent estimation, learning, and optimal play, it is shown that the proposed mechanism performs robustly even in such dynamic environments. Comparison of the proposed mechanism to other reasonable benchmark strategies in simulation confirms that this mechanism significantly enhances the performance of CRNs.

Distributed adaptive beam nulling to mitigate jamming in 3D UAV mesh networks

With the advancement of unmanned aerial vehicles (UAV), 3D wireless mesh networks will play a crucial role in next generation mission critical wireless networks. Along with providing coverage over difficult terrain, it provides better spectral utilization through 3D spatial reuse. However, being a wireless network, 3D meshes are vulnerable to jamming/disruptive attacks. A jammer can disrupt the communication, as well as control of the network by intelligently causing interference to a set of nodes. This paper presents a distributed mechanism of avoiding jamming attacks by means of 3D spatial filtering where adaptive beam nulling is used to keep the jammer in null region in order to bypass jamming. Kalman filter based tracking mechanism is used to estimate the most likely trajectory of the jammer from noisy observation of the jammers position. A beam null border is determined by calculating confidence region of jammers current and next position estimates. An optimization goal is presented to calculate optimal beam null that minimizes the number of deactivated links while maximizing the higher value of confidence for keeping the jammer inside the null. The survivability of a 3D mesh network with a mobile jammer is studied through simulation that validates an 96.65% reduction in the number of jammed nodes.

Implementation of 3D Obstacle Compliant Mobility Models for UAV Networks in ns-3

UAV networks are envisioned to play a crucial role in the future generations of wireless networks. The mechanical degrees of freedom in the movement of UAVs provides various advantages for tactical and civilian applications. Due to the high cost of failures in system-based tests, initial analysis and refinement of designs and algorithms for UAV applications are performed through rigorous simulations. Current trend of UAV specific simulators is mainly biased towards the mechanical properties of flying. For network-centric simulations, the intended measurements on the performance of protocols in mobile scenarios are conventionally captured from general-purpose network simulators, which are not natively equipped with comprehensive models for 3D movements of UAVs. To facilitate such simulations for UAV systems, this paper presents different mobility models for emulation of the movement of a UAV. Detailed description of three mobility models (random walk, random direction, and Gauss-Markov) are presented, and their associated movement patterns are characterized. This characterization is further extended by considering the effect of large obstacles on movement patterns of nodes following the three models. The mobility models are prepared as open-source add-ons for ns-3 network simulator.

Adaptive beam nulling in multihop ad hoc networks against a jammer in motion

Abstract In multihop ad hoc networks, a jammer can drastically disrupt the flow of information by intentionally interfering with links between a subset of nodes. The impact of such attacks can escalate when the jammer is moving. As a countermeasure for such attacks, adaptive beam-forming techniques can be employed for spatial filtering of the jamming signal. This paper investigates the performance of adaptive beam nulling as a mitigation technique against jamming attacks in multihop ad hoc networks. Considering a moving jammer, a distributed beam nulling framework is proposed. The framework uses periodic measurements of the RF environment to detect direction of arrival (DoA) of jamming signal and suppresses the signals arriving from the current and predicted locations of the jammer. Also, in the calculation of the nulled region, this framework considers and counters the effects of randomness in the mobility of the jammer, as well as errors in beam nulling and DoA measurements. Survivability of links and connectivity in such scenarios are studied by simulating various node distributions and different mobility patterns of the attacker. Also, the impact of errors in the estimation of DoA and beam-forming on the overall network performance is also examined. In comparison with an omnidirectional configuration, results indicate a 57.27% improvement in connectivity under jamming when the proposed framework is applied.

Enhancing performance and longevity of multi-radio multi-channel hetnets through dynamic path-assignment

In this paper, we present a novel approach to assign paths to data streams in a mission-centric heterogeneous wireless mesh network where nodes have multi-channel radio interfaces. Different than conventional packet-switching routing, our approach assigns the paths using a link utility based on sub-topologies of non-orthogonal frequencies. We use a graph coloring algorithm to calculate the utility of each link. We then propose two path assignment strategies: (i) single path, where each data stream traverse a unique path, and (ii) split-path, where the flows can be divided into multiple paths. Results show no best strategy fits all scenarios. Instead, in different situations, different algorithms are better suited.

LOS discovery for highly directional full duplex RF/FSO transceivers

Full duplex directional Radio Frequency (RF) / Free-Space-Optical (FSO) transceivers are envisioned to play a great role in future generation wireless networks. They provide benefits in terms of better throughput, enhanced spectrum utilization and lower interference from unwanted sources. However, the stringent requirement of line-of-sight (LOS) communication makes it tough for a mobile node to maintain a link without a-priori information about its neighbors position. Hence, neighbor discovery takes a very crucial role in mobile ad hoc networks with directional transceivers. In this paper, we focus on neighbor discovery using full duplex directional transceivers. We consider two nodes that can discover each other by steering their transceivers with a randomly chosen angular speed and performing a simple three way handshaking protocol. We provide a theoretical analysis of the proposed neighbor discovery method. Additionally, we propose an algorithm where each node chooses its transceivers angular speed and renews it if the neighbor is not discovered within an optimal time interval. We evaluate the algorithm via simulations and show its effectiveness under various scenarios.

LOS discovery in 3D for highly directional transceivers

Directional Radio Frequency (RF) / Free-Space-Optical (FSO) transceivers have the potential to play a significant role in future generation wireless networks. They are advantageous in terms of improved spectrum utilization, higher data transfer rate, and lower probability of interception from unwanted sources. Despite these advantages, communications using directional transceivers require establishment and maintenance of line-of-sight (LOS). Thus, establishment of the communication link or neighbor discovery plays an important role in mobile ad hoc networks with RF/FSO directional transceivers. We consider two nodes (Unmanned Aerial Vehicles (UAVs) or Quadcopters) hovering in 3D space, each with one directional transceiver mounted on a mechanically steerable spherical structure/head, with which they can scan 360° in the horizontal plane and 360° in the vertical plane. We propose a novel scheme that deals with the problem of automatic discovery and establishment of LOS alignment between these nodes. We performed extensive simulations to show the effectiveness of the proposed neighbor discovery method. The results show that, using such mechanically steerable directional transceivers, it is possible to establish communication links to similar neighboring nodes within minimal discovery times.