A Green TDMA Scheduling Algorithm for Prolonging Lifetime in Wireless Sensor Networks

Fast data collection is one of the most important research issues for Wireless Sensor Networks (WSNs). In this paper, a TMDA based energy consumption balancing algorithm is proposed for the general k-hop WSNs, where one data packet is collected in one cycle. The optimal k that achieves the longest network life is obtained through our theoretical analysis. Required time slots, maximum energy consumption and residual network energy are all thoroughly analyzed in this paper. Theoretical analysis and simulation results demonstrate the effectiveness of the proposed algorithm in terms of energy efficiency and time slot scheduling

Wireless industrial monitoring and control networks: the journey so far and the road ahead

While traditional wired communication technologies have played a crucial role in industrial monitoring and control networks over the past few decades, they are increasingly proving to be inadequate to meet the highly dynamic and stringent demands of today’s industrial applications, primarily due to the very rigid nature of wired infrastructures. Wireless technology, however, through its increased pervasiveness, has the potential to revolutionize the industry, not only by mitigating the problems faced by wired solutions, but also by introducing a completely new class of applications. While present day wireless technologies made some preliminary inroads in the monitoring domain, they still have severe limitations especially when real-time, reliable distributed control operations are concerned. This article provides the reader with an overview of existing wireless technologies commonly used in the monitoring and control industry. It highlights the pros and cons of each technology and assesses the degree to which each technology is able to meet the stringent demands of industrial monitoring and control networks. Additionally, it summarizes mechanisms proposed by academia, especially serving critical applications by addressing the real-time and reliability requirements of industrial process automation. The article also describes certain key research problems from the physical layer communication for sensor networks and the wireless networking perspective that have yet to be addressed to allow the successful use of wireless technologies in industrial monitoring and control networks

Chain Routing for Convergecast Small Scale Wireless Sensor Networks

Wireless sensor networks have many applications involving autonomous sensors transmitting their data to a sink placed in the network. A protocol by name Chain Routing for Convergecast Small Scale (CRCSS) Wireless sensor networks is proposed in this paper. The set of sensor nodes in the network send the data periodically to the sink located in the area of interest. The nodes who cannot reach sink in one hop choose one of the neighbours for forwarding the data to the sink by forming a chain of links. The selection of forwarding node and the waiting period before forwarding plays an important role in the protocol. The proposed CRCSS protocol exhibits improvement in energy spent per packet and latency per packet for a wireless sensor network as compared to ConverSS protocol for small scale wireless sensor networks. In CRCSS protocol energy spent per packet is independent of the network radius

Congestion Avoidance Energy Efficient MAC Protocol for Wireless Sensor Networks

Wireless Sensor Network (WSNs) are generally energy-constrained and resource-constrained. When multiple simultaneous events occur in densely deployed WSNs, nodes near the base station can become congested, decreasing the network performance. Additionally, multiple nodes may sense an event leading to spatially-correlated contention, further increasing congestion. In order to mitigate the effects of congestion near the base station, an energy-efficient Media Access Control (MAC) protocol that can handle multiple simultaneous events and spatially-correlated contention is needed. Energy efficiency is important and can be achieved using duty cycles but they could degrade the network performance in terms of latency. Existing protocols either provide support for congestion near the base station or for managing spatially-correlated contention. To provide energy-efficiency while maintaining the networks performance under higher traffic load, we propose an energy-efficient congestion-aware MAC protocol. This protocol provides support for congestion near the base station and spatially-correlated contention by employing a traffic shaping approach to manage the arrival times of packets to the layers close to the base station. We implemented our protocol using the ns-2 simulator for evaluating its performance. Results show that our protocol has an improvement in the number of packets received at the base station while consuming less energy

Secure Minimum Time Data Collection (SMTDC) protocol for wireless sensor networks

Recent work has shown that a mobile data collector moving along a predefined trajectory can improve the real-time data collection duration and efficiency in wireless sensor networks (WSN). Due to the fixed trajectory and limited communication range, data collection is conducted using a many-to-one communication pattern known as convergecast. However, because of the confidentiality concern of data being transmitted, security issues such as security key leakage, eavesdropping, and malicious attack raise significant challenges in minimizing the data collection time. To address this issue, we present the design and implementation of the Secure Minimum Time Data Collection (SMTDC) protocol, a tree formulated, and time-scheduled protocol for large scale, stationary, hardware-limited WSN. SMTDC can cooperate with many existing security communication frameworks. During the tree formation phase of SMTDC, we build well-balanced optimized trees that have the potential for minimum data collection time. We formulate our approach as an integer linear programming problem and solve it using linear relaxation based iterative rounding (LR-IR). During the time scheduling phase of SMTDC, we use a heuristic time-slot arrangement algorithm to solve the tree scheduling problem. The proposed algorithms and schemes are validated through simulation experiments using GUROBI solver and OMNET++ under realistic WSN topology. The result shows that SMTDC tree formation outperforms other algorithms in building a more effectively secure and load-balanced tree, and SMTDC scheduling significantly improves the data collection time over pre-generated tree topology

Dynamic cluster scheduling for cluster-tree WSNs

While Cluster-Tree network topologies look promising for WSN applications with timeliness and energy-efficiency requirements, we are yet to witness its adoption in commercial and academic solutions. One of the arguments that hinder the use of these topologies concerns the lack of flexibility in adapting to changes in the network, such as in traffic flows. This paper presents a solution to enable these networks with the ability to self-adapt their clusters’ duty-cycle and scheduling, to provide increased quality of service to multiple traffic flows. Importantly, our approach enables a network to change its cluster scheduling without requiring long inaccessibility times or the re-association of the nodes. We show how to apply our methodology to the case of IEEE 802.15.4/ZigBee cluster-tree WSNs without significant changes to the protocol. Finally, we analyze and demonstrate the validity of our methodology through a comprehensive simulation and experimental validation using commercially available technology on a Structural Health Monitoring application scenario

Generic sensor network architecture for wireless automation (GENSEN)

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Rollout algorithm based duty cycle control with joint optimisation of delay and energy efficiency for beacon-enabled IEEE 802.15.4 networks

Duty cycle control is applied in IEEE 802.15.4 medium access control (MAC) protocol to reduce energy consumption. A low duty cycle improves the energy efficiency but it reduces the available transmission time, thereby increases the end-to-end delay. Thus, it is a challenge issue to achieve a good trade-off between energy efficiency and delay. In this paper, we study a duty cycle control problem with the aim of minimising the joint-cost of energy consumption and end-to-end delay. By applying dynamic programming (DP), the optimal duty cycle control is derived. Furthermore, to ensure the feasibility of implementing the control on computation limited sensor devices, a low complexity rollout algorithm based duty cycle control (RADutyCon) is proposed. The joint-cost upper bound of the proposed RADutyCon is investigated. Simulation results show that RADutyCon can effectively reduces the joint-cost of energy consumption and end-to-end delay under various network traffic. In addition, RADutyCon achieves an exponential reduction of computation complexity compared with DP optimal control