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Abstract The Threshold-based Low-energy Adaptive Clustering Hierarchy (T-LEACH) protocol declares that cluster heads do not have to turn over every round but rather every batch of rounds. In other words, nodes keep serving as cluster heads as long as their energy is higher than a threshold energy. This article imposes upon major drawbacks of T-LEACH protocol and presents a Modified Threshold-based Cluster Head Replacement (MT-CHR) protocol. In the MT-CHR protocol, a new probability of being a cluster head, for any node in any round, has been proposed which agrees fairly with the assumptions introduced in LEACH protocol. Moreover, a new expression for threshold energy is proposed in which delaying the first node death and avoiding any data loss are taken into consideration. The performance of MT-CHR is evaluated using alive nodes, network lifetime, as well as network utilization performance metrics. The results are further compared with those obtained importantly from LEACH and T-LEACH protocols and the contributions of MT-CHR protocol are extremely impressive. As far as the real sensor network is concerned, the MT-CHR protocol is highly applicable and very effective as long-lasting networks are ascertained. [ABSTRACT FROM AUTHOR]

In Wireless Sensor Networks (WSNs), sensors are spread over a remote and hardly accessed sensing zone. In this situation, Unmanned Aerial Vehicles (UAVs) allow to facilitate the data gathering from sensors in real time. In the present paper, we consider an optical UAV network that allows the real time data distribution to a base station, based on multiple collection trees and multiple base stations. Each UAV is identified by an optical codeword with adequate structure to reduce the codeword management process implied by the UAV mobility. Using the attributed codewords, each UAV can optically switch the gathered data to reach a base station for processing. Furthermore, we present quality-based attachment and re-attachment procedures allowing to an UAV to attach and re-attach to a tree whether it notices the quality degradation of its link to the collection tree. [ABSTRACT FROM AUTHOR]

Wireless Sensor Networks (WSNs) are used for environmental monitoring. In recent years, energy constraints have led us to develop sensor nodes that harvest energy from the environment. WSNs improve performances by using techniques such as routing and clustering, by harvesting energy from the environment. These networks are called Energy Harvesting Wireless Sensor Network (EH-WSN). Due to the unique features of EH-WSNs, typical WSN clustering and routing methods are inefficient for EH-WSN. In this paper, we propose a novel hybrid methodology involving static and dynamic clustering operations. It uses a distributed-centralized approach and multi-hop routing and considers criteria, such as the energy level, the amount of harvested energy and the number of neighbors in the clustering process. Simulation results show that the proposed method improves the network stability and efficiency, comparing to other methods. [ABSTRACT FROM AUTHOR]

Wireless sensor networks are formed by a large number of sensor nodes which are commonly known as motes. In the past few years, several reliable, congestion controlled and energy efficient transport layer protocols in wireless sensor networks have been developed and proposed in the literature. In this paper, we have presented a hybrid and dynamic reliable transport protocol which provides the mechanism to dynamically assign the timing parameters to the nodes as well as enhance the protocol performance by using a hybrid Acknowledgement/Negative Acknowledgement scheme. The performance of proposed protocol is tested under TinyOS Simulator varying different parameters and protocol settings and found that proposed protocol is able to program all the nodes when given proper pump/fetch ratios, is able to solve the booting sensor nodes problem by being able to wait till all the nodes finished booting and solves the all-packets-lost problem by acknowledging the receipt of its first packet delivered that is the inform message. [ABSTRACT FROM AUTHOR]

Mobile ad hoc networks (MANETs) are wireless, self-organizing and infrastructure-less networks with nodes that rely on power. Hence, there is a need for an energy-aware and energy-efficient routing protocol. To enhance the lifetime of nodes and network performance, intervals such as the Hello-Interval and TC-Interval of the optimized link state routing (OLSR) protocol are tuned. Additionally, the residue forecast algorithm is incorporated with the protocol, yielding the Hello-Interval 1, TC-Interval 3 residue forecasted optimized link state routing (HTR-OLSR) protocol. In addition, the modified multipoint relay (MPR) selection plays a vital role in energy consideration. In the case of dynamic networks, a gain in throughput of approximately 10% to 15% is obtained. [ABSTRACT FROM AUTHOR]

This paper proposes a cross-layer mobility support scheme for the IPv6 over low-power wireless personal area network (6LoWPAN) wireless sensor network (WSN). This scheme combines the handover in the network layer (L3) with the handover in the link layer (L2) so that the L3 handover and the L2 one can be performed simultaneously. During the L3 handover process, a sensor node neither needs a care-of address nor participates in the handover process. During the L2 handover process, a node uses the channel information to directly achieve the L2 handover without scanning all channels. Finally, this paper analyzes and evaluates the performance of this protocol, and the data results show that this protocol improves the mobility handover performance. [ABSTRACT FROM AUTHOR]

Designing a lightweight, secure communication protocol for Wireless Sensor Networks (WSNs) remains a challenging issue since sensor networks are resource limited and are left unattended. Sensor nodes in WSNs are subjected to varying forms of attacks. An adversary may destroy or damage the communications done in multi-hop WSNs by means of packet dropping and modification. Hence it is essential to have an efficient cryptographic scheme to protect the communications done in WSNs. This study introduces a Reliable Anonymous Secure Packet forwarding (RASP) scheme that can prevent not only traffic analysis attack but also the attacks done through compromised forwarding nodes. The mechanisms followed here are effective with low computation and communication overhead. The performance of the proposed scheme is evaluated over NS2 with a series of simulation. The simulated results show that the proposed scheme performs better than other comparable schemes. [ABSTRACT FROM AUTHOR]

Highlights: [•] There is a lack of end-to-end security mechanisms tailored to IP-enabled sensors. [•] Ladon is proposed as end-to-end authentication and authorization protocol. [•] We evaluate the time and energy cost of executing Ladon on the protected sensors. [•] Ladon is proved to be a suitable security protocol for resource-deprived devices. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we discuss the design of a new Medium Access Control (MAC) protocol, SRI-MAC (Synchronous Receiver Initiated MAC), for wireless sensor networks whose goal is to extend the lifetime of the network by avoiding major energy waste causes, such as collisions, overhearing and idle listening. SRI-MAC is designed on the basis of synchronized duty cycled MAC protocols. The nodes in SRI-MAC synchronize each other to avoid data packet collisions. SRI-MAC uses receiver-initiated data transmission in order to efficiently and effectively operate over a wide range of traffic loads. It employs an adaptive beacon and a series of RTS/CTS (Request To Send/Clear To Send) packets to reduce duty cycle and minimize idle listening. In SRI-MAC, the senders remain active and wait silently until the receiver explicitly signifies when to start data transmission by sending CTS packet. If the node is not the intended sender, it returns to sleep immediately and continues its sleep as if the medium had been idle. Analytical and Simulation results show that SRI-MAC reduces the energy consumption and achieves an obvious improvement on the network lifetime. [Copyright &y& Elsevier]

Highlights: [•] We propose a novel clustering protocol ECDS, which considers coverage and energy efficiency simultaneously. [•] We propose two new metrics CI p and CI a and for coverage performance. [•] ECDC has better performance compared with some other clustering protocols. [ABSTRACT FROM AUTHOR]

Abstract: Wireless Sensor Network (WSN) has emerged as a system composed of numerous sensor nodes to collect information, process and deliver the data to the central sink. Existing protocols like Sensor-MAC (SMAC) and Pattern MAC (PMAC) reduces energy consumption from collision, overhearing, control packet overhead and idle listening. Collision is one of the main sources of energy wastage. In pattern MAC protocol, the span of time slot TE in Pattern Exchange Time Frame (PETF) is long enough to broadcast the pattern. A large contention window at the beginning of each PETF time slot is to avoid collision. However, if longer PETF is used, the over head and delay will be more. Hence, the proposed algorithm balances collision and delay. A collision controlled parameter alpha is introduced to compromise delay and collision. From the results, it is observed that, 2.3% of energy is saved. [Copyright &y& Elsevier]

The lightweight sensors gain rapid growth for the development of emerging technologies due to multi aspects. Recently, many applications are integrating with the cloud services for storage and processing a large amount of observing data, however, the transitory and time-dependent environment needs valuable performance. Also, reliable and error-free data transmission is an important factor for green systems. Moreover, most of the proposed green networks may be exposed to unspecified events due to the broadcast nature of the unreserved medium. This research paper presents a secured mobile sensor network based protocol for smart data gathering with cloud services (S-SDC), which aims to attain information distribution in dynamic networks using mobile sensors with minimum loss and power consumption. Also, it ensures network availability and consistency for the collected data with the cloud corporations and increases authoritative routing. The simulation results and their analysis are proven the significant performance of the proposed protocol. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: It is well known that the data of large-scale and dense wireless sensor network has high spatial correlativity. According to the monitoring of a particular event, a new medium access control (MAC) protocol based on perceived data reliability and spatial correlation is proposed in this paper. In this protocol, a ring-shaped space correlation model is established. The nodes close to information source is attributed them high priority in access channel so as to make sure the high quality data send successfully to the sink node and increase the data transferring efficiency. The new protocol can make the received data reflect the real physical phenomenon. At the same time, it can make the data transmission of the nodes far to information source be brought down and the amount of required data nodes be reduced. So the new protocol can prolong lifetime of the whole network. Our simulation results show that the new MAC protocol can supply better network service under low energy consumption and transmission delay. This is very useful for all kinds of mobile services of Internet of Things. [Copyright &y& Elsevier]

Abstract: This article reviews the state-of-the-art energy-efficient contention-based and scheduled-based medium access control (MAC) protocols for mobile sensor networks (MSNs) by first examining access schemes for wireless sensor networks (WSNs). Efficient and proper mobility handling in sensor networks provides a window of opportunity for new applications. Protocols, such as S-MAC, reduce energy consumption by putting nodes to sleep after losing to channel contention or to prevent idling. Sleeping is a common method for energy-efficient MAC protocols, but delay depends on sleep duration or frame time, and longer delays lead to higher packet lost rate when nodes are unsynchronized due to network mobility. MS-MAC extends S-MAC to include mobility-awareness by decreasing this sleep duration when mobility is detected. S-MAC with extended Kalman filter (EKF) reduces mobility-incurred losses by predicting the optimal data frame size for each transmission. MMAC utilizes a dynamic mobility-adaptive frame time to enhance TRAMA, a scheduled-based protocol, with mobility prediction. Likewise, G-MAC utilizes TDMA for cluster-based WSNs by combining the advantages of contention and contention-free MACs. Z-MAC also combines both methods but without clustering and allows time slot re-assignments during significant topology changes. All of the above MAC protocols are reviewed in detail. [Copyright &y& Elsevier]

Abstract: Wireless multicast for multihop ad-hoc networks ensures that the same information is delivered efficiently to multiple recipients simultaneously. However, existing protocols ignore the real-time nature of many wireless applications such as real-time video and audio communications in mesh and ad-hoc networks. Further, devices in such networks are typically energy-constrained, i.e., multicast protocols have to trade off timeliness with energy efficiency. This paper presents RTMC, a real-time multicast protocol for wireless multihop networks that allows receivers to specify their individual real-time constraints and establishes multicast trees such that receivers’ deadlines are met and overall energy consumption in the network is reduced. Toward this end, RTMC relies on dynamically prioritized packet scheduling on forwarding nodes, prioritized channel access at the MAC layer, feedback control for latency management, tree adaptations to address mobility, dynamic subscriptions and unsubscriptions, and adaptations to address link breakages. Simulation results show that, compared to non-real-time multicast techniques, RTMC can provide user-specific latency management while reducing the energy consumption in the network. [Copyright &y& Elsevier]

Abstract: Minimizing energy dissipation and maximizing network lifetime are among the central concerns when designing applications and protocols for sensor networks. Clustering has been proven to be energy-efficient in sensor networks since data routing and relaying are only operated by cluster heads. Besides, cluster heads can process, filter and aggregate data sent by cluster members, thus reducing network load and alleviating the bandwidth. In this paper, we propose a novel distributed clustering algorithm where cluster heads are elected following a three-way message exchange between each sensor and its neighbors. Sensor’s eligibility to be elected cluster head is based on its residual energy and its degree. Our protocol has a message exchange complexity of and a worst-case convergence time complexity of . Simulations show that our algorithm outperforms EESH, one of the most recently published distributed clustering algorithms, in terms of network lifetime and ratio of elected cluster heads. [Copyright &y& Elsevier]