Yuyan Xue

A Key Management Protocol for Wireless Sensor Networks with Multiple Base Stations

Most of the proposed key management protocols for wireless sensor networks (WSNs) in the literature assume that a single base station is used and that the base station is trustworthy. However, there are applications in which multiple base stations are used and the security of the base stations must be considered. This paper investigates a key management protocol in wireless sensor networks which include multiple base stations. We consider the situations in which both the base stations and the sensor nodes can be compromised. The proposed key management protocol, mKeying, includes two schemes, a key distribution scheme, mKeyDist, supporting multiple base stations in the network, and a key revocation scheme, mKeyRev, used to efficiently remove the compromised nodes from the network. Our analyses show that the proposed protocol is efficient and secure against the compromise of the base stations and the sensor nodes.

SDRCS: A service-differentiated real-time communication scheme for event sensing in wireless sensor networks

Real-time communication is crucial for wireless sensor networks (WSNs) to accomplish collaborative event sensing tasks with specific timing constraints. In this work, a service-differentiated real-time communication scheme (SDRCS) is developed to provide soft real-time guarantees for event-based traffic in WSNs. SDRCS features a cross-layer packet forwarding design to integrate the real-time routing functionality with a novel prioritized medium access control scheme. Based on this design, SDRCS performs distributed packet traversal speed estimation for traffic classification and admission control. SDRCS also performs prioritized packet forwarding so that the routing decisions are locally performed for maximized packet traversal speed. SDRCS requires no extra hardware for localization, transmission power adaptation or multi-channel transmission. It also adapts well to network dynamics, such as channel quality and communication voids. Performance evaluations show that SDRCS significantly improves the on-time delivery ratio and service-differentiation granularity for mixed priority traffic flows in unsynchronized WSNs, compared with currently used communication schemes. SDRCS also provides higher end-to-end throughput in terms of supporting higher source data rates with tight end-to-end latency requirements.

Cost Efficiency of Anycast-Based Forwarding in Duty-Cycled WSNs with Lossy Channel

Anycasting has been proposed recently as an efficient communication method for asynchronous duty-cycled wireless sensor networks. However, the interdependencies between end-to-end communication cost and the anycasting design parameters have not been systematically studied. In this paper, a statistical end-to-end cost model is presented to capture the end-to-end latency and energy consumption of anycasting operation under a realistic wireless channel model. By exploring the relationship between the end-to-end cost efficiency and the forwarding decision dependent anycasting design parameters, two anycasting forwarding metrics are proposed for fully distributed forwarding decision. By exploring the relationship among the preamble length, the size of the forwarding set and the achievable end-to-end cost efficiency, a series of preamble length control guidelines are proposed for low and extremely low duty-cycled WSNs. According to our analytical results and simulation validation, the proposed forwarding metrics help reduce the end-to-end latency and energy consumption by about

LTRES: A loss-tolerant reliable event sensing protocol for wireless sensor networks

55\%

A service-differentiated real-time communication scheme for wireless sensor networks

for anycasting with moderate preamble length, compared with the existing heuristic forwarding metrics. The proposed preamble length control guidelines help reduce, by more than half, the end-to-end energy and latency costs in low and extremely-low duty-cycled WSNs.

Providing Reliable Data Transport for Dynamic Event Sensing in Wireless Sensor Networks

Many Wireless Sensor Network (WSN) transport protocols proposed in recent studies focus on providing end-to-end reliability as in TCP. However, traditional end-to-end reliability enforcement is energy and time consuming for common loss-tolerant applications in WSNs. In this paper, a Loss-Tolerant Reliable Event Sensing protocol (LTRES) is proposed based on the particular reliability requirements for dynamic event observation in WSNs. According to the application-specific requirements, a reliable event sensing threshold at the transport layer is determined by the sink. A distributed source rate adaptation mechanism is designed, incorporating a loss rate based lightweight congestion control mechanism, to regulate the data traffic injected into the network so that the reliability requirements can be satisfied. An equation based fair rate control algorithm is designed to improve the fairness among the traffic flows sharing the congestion path. The performance evaluations show that LTRES can provide event-based loss-tolerant reliable data transport service for multiple events with short convergence time, low loss rate and high overall bandwidth utilization.

A security framework for wireless sensor networks utilizing a unique session key

Supporting end-to-end real-time communication is important for wireless sensor networks (WSNs) to acomplish the collaborative sensing tasks with specific timing constraints. However, without considering the unique constraints for WSNs, many existing real-time communication protocols prove to be infeasible for low-cost WSNs. In this paper, we propose a novel real-time communication scheme (RCS) to provide service-differentiated soft real-time guarantees for end-to-end communication in WSNs. We use hop-based geographic grouping to enable location awareness for sensor nodes with extremely low control overhead.We use dynamic forwarding with load-balanced receiver contention to provide a light-weight, yet efficient, routing technique, which can be easily adapted for duty cycle design. We use polling contention period based real-time MAC support to improve the service-differentiation granularity with better bandwidth utilization. The performance evaluation shows that our scheme can achieve low end-to-end latency, high on-time delivery ratio, fine services-differentiation granularity with load-balance for real-time traffic in unsynchronized low-cost WSNs.

A distributed reliable data transport strategy for event based wireless sensor networks

In this paper, we propose a loss tolerant reliable (LTR) data transport mechanism for dynamic event sensing (LT-RES) in WSNs. In LTRES, a reliable event sensing requirement at the transport layer is dynamically determined by the sink. A distributed source rate adaptation mechanism is designed, incorporating a loss rate based lightweight congestion control mechanism, to regulate the data traffic injected into the network so that the reliability requirement can be satisfied. An equation based fair rate control algorithm is used to improve the fairness among the LTRES flows sharing the congestion path. The performance evaluations show that LTRES can provide LTR data transport service for multiple events with short convergence time, low lost rate and high overall bandwidth utilization.

An Efficient Scheme for Removing Compromised Sensor Nodes from Wireless Sensor Networks

Key management is a core mechanism to ensure the security of applications and network services in wireless sensor networks. It includes two aspects: key distribution and key revocation. Many key management protocols have been specifically designed for wireless sensor networks. However, most of the key management protocols focus on the establishment of the required keys or the removal of the compromised keys. The design of these key management protocols does not consider the support of higher level security applications. When the applications are integrated later in sensor networks, new mechanisms must be designed. In this paper, we propose a security framework, uKeying, for wireless sensor networks. This framework can be easily extended to support many security applications. It includes three components: a security mechanism to provide secrecy for communications in sensor networks, an efficient session key distribution scheme, and a centralized key revocation scheme. The proposed framework does not depend on a specific key distribution scheme and can be used to support many security applications, such as secure group communications. Our analysis shows that the framework is secure, efficient, and extensible. The simulation and results also reveal for the first time that a centralized key revocation scheme can also attain a high efficiency.

Loss-Rate Based Reliable Data Transport Mechanism for Dynamic Event Sensing in Wireless Sensor Networks

(iii) f is a bijection. A wireless sensor network (WSN) is composed of a large number of densely deployed sensing devices, which are equipped with limited computing and radio communication capabilities. The objective of a WSN is to reliably estimate the features of a surveillance area, especially the events of interest, relying on the collective effort of sensor nodes observing the physical phenomenon. An important feature of WSNs is the possible redundancy of the data continuously collected by the sensor nodes, i.e. only a limited number of sensor measurements collected from the sensor nodes working at certain reporting frequencies might be adequate to convey the event feature to the sink with a given loss tolerance. A key underlying observation is that the reporting frequencies of the sensor nodes determine not only the amount of useful data received at the sink, but also the amount of traffic injected into the sensor network. Therefore, if we can adaptively regulates the reporting frequencies of sensor nodes based on the dynamic environment features and network conditions, we can minimize the traffic injected into the WSN while guaranteeing the required event transport reliability achieved at the sink. Further, it helps to decrease the unnecessary in-network communication, thus helping cut down the energy consumption and bandwidth utilization. In this paper, we propose a distributed reliable data transport strategy for event based WSN in order to solve the above