Amrita Ghosal

A survey on mobility-assisted localization techniques in wireless sensor networks

Identifying locations of sensor nodes in wireless sensor networks (WSNs) is significant for both network operations and most application level tasks. Although geographical positioning system (GPS) based localization schemes are used for determining node locations but the cost of GPS devices and non-availability of GPS signals in indoor environments prevent their use in large scale WSNs. A substantial amount of research work exist that intend at obtaining precise and relative spatial locations of sensor nodes without requiring large amount of specialized hardware. Mobility-assisted localization is one typical approach that significantly reduces the implementation cost by using limited number of mobile anchors. In this survey, we present key issues and inherent challenges faced by the mobility-assisted localization techniques in WSNs. We take a closer look at the algorithmic approaches of various important fine-grained mobility-assisted localization techniques applicable in WSNs. In addition, we highlight the error refinement mechanisms adopted by the state-of-the-art works associated with their approaches. Well known mobile anchor trajectories presented in existing works are also reviewed. Finally, open research issues are discussed for future research scope in this field.

A survey on mobile anchor assisted localization techniques in wireless sensor networks

Identifying locations of sensor nodes in wireless sensor networks (WSNs) is significant for both network operations and most application level tasks. Although, geographical positioning system (GPS) based localization schemes are used for determining node locations but the cost of GPS devices and non-availability of GPS signals in indoor environments prevent their use in large scale WSNs. A substantial amount of research work exist that intend at obtaining precise and relative spatial locations of sensor nodes without requiring large amount of specialized hardware. Mobile anchor assisted localization is one typical approach that significantly reduces the implementation cost by using limited number of mobile anchors. In this survey, we present key issues and inherent challenges faced by the mobile anchor assisted localization techniques in WSNs. We take a closer look at the algorithmic approaches of various important fine-grained mobile anchor assisted localization techniques applicable in WSNs. In addition, we highlight the error refinement mechanisms adopted by the state-of-the-art works associated with their approaches. Well known mobile anchor trajectories presented in existing works are also reviewed. Finally, open research issues are discussed for future research scope in this field.

A dynamic TDMA based scheme for securing query processing in WSN

Nodes in a wireless sensor network (WSN) are generally deployed in unattended environments making the nodes susceptible to attacks. Therefore, the need of defending such attacks becomes a big challenge. We propose a scheme to build a security mechanism in a query-processing paradigm within WSN. The scheme is capable of protecting replay attack while preserving essential properties of security such as authentication, data integrity and data freshness. The solution is made lightweight using symmetric key cryptography with very short-length key. Further, the key used in our scheme is neither pre-deployed nor is transmitted directly. The key information is established among nodes through an efficient use of one variant of dynamic TDMA mechanism which ensures security of key. Another variant of dynamic TDMA is used to make the scheme bandwidth saving, an essential quality of WSN. Performance of the scheme is analyzed in terms of storage, computation and communication overhead. Finally the analytical results are compared with two of the existing schemes including the previous version of the present scheme that show significant reduction of all such overheads thereby proving the suitability of the proposed scheme for a resource-constrained network like WSN.

A Location-Wise Predetermined Deployment for Optimizing Lifetime in Visual Sensor Networks

Visual sensor networks are receiving significant attention due to their potential applications ranging from surveillance to tracking domains. Nevertheless, due to the funneling effect, the unbalanced energy usage among visual sensor nodes (SNs) increases and leads to premature decrease in network lifetime. First, considering Rayleigh fading channel and routing models, we analyze the optimization of network lifetime by balancing the energy consumption among different SNs. From the analysis, it is revealed that the number of SNs and relay nodes and their locations have significant influence on limiting the energy hole problem and optimization of network lifetime. Based on the derived principle of energy balancing, we develop a heterogeneous SNs deployment strategy leading to optimization in network lifetime. Exhaustive simulation is performed, primarily to measure the extent of achieving our design goal of optimizing network lifetime while attaining energy balancing. We also measure the effect of placement errors on the performance and robustness of the scheme. The results show that even in the presence of placement error the performance is comparable and provides better robustness compared with the competing scheme. Further, the simulation results show that our scheme does not compromise with other performance metrics, e.g., end-to-end delay and throughput, while achieving the design goal. Finally, all the comparative results confirm our schemes supremacy over the competing schemes.

A lightweight security scheme for query processing in clustered wireless sensor networks

Graphical abstractDisplay Omitted Low-overhead secured query-processing mechanism in clustered WSN environment.Preserves security features- confidentiality, integrity and defence against replay attack.Query is sent from base station to cluster heads in encrypted form.The cluster heads register their member nodes by exchanging messages.The cluster heads send aggregated responses to the base station. When wireless sensor networks (WSNs) are deployed in areas inaccessible by human beings, security becomes extremely important, as they are prone to different types of malicious attacks. We propose a scheme to build a security mechanism in a query-processing paradigm within WSNs with clustered architecture. This work aims to preserve the basic security features such as confidentiality and integrity as well as to protect from replay attack in presence of mote class attacker. Considering the limitations of such an attacker, the probability of attacking cluster head and member nodes is higher than attacking the base station. Paying attention to this fact, in all communication between cluster head and member nodes, the key is neither transmitted nor pre-deployed. Performance of the scheme is evaluated and compared through qualitative and quantitative analyses; results show the present schemes dominance over the competing schemes.

Is sensor deployment using Gaussian distribution energy balanced

Energy is one of the scarcest resources in wireless sensor network (WSN). One fundamental way of conserving energy is judicious deployment of sensor nodes within the network area so that energy flow remains balanced throughout the network. Node deployment using Gaussian distribution is a standard practice and is widely acceptable when random deployment is used. Initially, an analysis is done to establish that Gaussian distribution based node deployment is not energy balanced. Standard deviation has been identified as the parameter responsible for energy balancing. A deployment strategy is proposed for energy balancing using customized Gaussian distribution by discretizing the standard deviation. Performance of the deployment scheme is evaluated in terms of energy balance and network lifetime. Simulation results demonstrate that the proposed deployment strategy significantly outperforms conventional Gaussian distribution based node deployment scheme in terms of the two performance metrics.

Ensuring basic security and preventing replay attack in a query processing application domain in WSN

Nodes in a wireless sensor network are susceptible to various attacks primarily due to their nature of deployment. Therefore, providing security to the network becomes a big challenge. We propose a scheme considering cluster architecture based on LEACH protocol to build a security mechanism in a query-processing paradigm within wireless sensor network. The scheme is capable of thwarting replay attack while ensuring essential properties of security such as authentication, data integrity and data freshness. Our scheme is lightweight as it employs symmetric key cryptography with very short-length key. We simulate our scheme to show its efficacy of providing basic security to the network as well as detecting replay attack in the sensor network. Further we compare our scheme with one of the existing schemes taking packet loss and packet rejection ratio as performance metrics.

A jamming defending data-forwarding scheme for delay sensitive applications in WSN

Wireless sensor network (WSN) has emerged as an important application area where nodes are generally placed in an unattended environment and therefore are vulnerable to attack by adversaries. Moreover in real time application domains delay even by fraction of a second may deceive the purpose of the application. Therefore, designing an attack-defending scheme for WSN without involving any additional delay in data-forwarding is an important challenge in this domain. The present work proposes a data-forwarding scheme having no additional delay to defend jamming attack in WSN. The scheme considers a multilayer architecture where the layers are made up of hexagonal cells each containing sensor nodes in the form of clusters. The nodes are randomly deployed throughout the network and clusters are formed so that every cell hosts two sets of clusters operating in two different predefined frequencies. We have provided design guideline to determine cell size in terms of network parameters. This guideline ensures that for a cluster head there is at least another cluster head at one-hop distance towards the sink and thereby ensures data-forwarding in shortest path. During data-forwarding, if a frequency is jammed, the cluster operating in that frequency becomes inoperative and the other cluster acts as back-up. We claim that the scheme defends jamming attack without incurring any additional delay and the claim is substantiated through simulation.

Estimating Delay in a Data Forwarding Scheme for Defending Jamming Attack in Wireless Sensor Network

Wireless sensor networks (WSNs) have emerged as an important application area resulting from the advancement of efficient short-range radio communication and miniaturization of computing devices. Nodes in such a network generally remain in an unattended environment and thereby they are prone to attack by adversaries. Therefore, the need of defending such attacks is of utmost importance. This paper presents a data forwarding scheme to defend jamming attack in WSN. The attack is defended at the cost of an affordable delay. The scheme considers a multi-level tier architecture based on clustering of nodes in each tier. Further the work identifies the parameters causing delay in presence of attack and analyses the impact of the parameter values in estimating delay. We claim that delay is affordable as it is independent of number of attacked-nodes rather it depends on number of tiers where attacked-node(s) belong. The claim is justified with proof.

Intrusion Detection in Wireless Sensor Networks: Issues, Challenges and Approaches

Wireless sensor networks (WSNs) have generated immense interest among researches for the last few years motivated by several theoretical and practical challenges. The increase in interest is mainly attributed to new applications designed with large scale networks consisting of devices capable of performing computations on the sensed data and finally processing the data for transmitting to remote locations. Providing security to WSNs plays a major role as these networks are generally deployed in inaccessible terrain and also for their communication being in the wireless domain. These reasons impose security mechanisms to be employed on the highly vulnerable sensor networks that are robust enough to handle attacks from adversaries. WSNs consist of nodes having limited resources and therefore classical security measures applicable in traditional networks cannot be applied here. So the need of the hour is using systems that lie within the boundary of the sensor nodes resource potential as well competent enough to handle attacks. Intrusion detection is one such defense used in sensor networks having the ability to detect unknown attacks and finding means to thwart them. Researches have found intrusion detection system (IDS) to be very much compatible in sensor networks. Therefore intrusion detection holds a very prominent research area for researchers. So familiarity with this promising research field will surely benefit the researchers. Keeping this in mind we survey the major topics of intrusion detection in WSNs. The survey work presents topics such as the architectural models used in the different approaches for intrusion detection, different intrusion detection techniques and highlights intrusion detection methods applicable for the different layers in sensor networks. The earlier achievements in intrusion detection in WSNs are also summarized along with more recent works and existing problems are discussed. We also give an insight into the possible directions for future work in intrusion detection involving different aspects in sensor networks.