A Distributed Consensus-Based Clock Synchronization Protocol for Wireless Sensor Networks

An energy-balancing, cross-layer data gathering protocol (EB-CLDG) for wireless sensor networks (WSNs) is presented in this paper. EB-CLDG is proposed for monitoring and periodic reporting applications and the network is organized into concentric tiers around the sink. An energy-balancing clustering algorithm is employed to mitigate the “hot spot” problem. Thus the number of clusters closer to the sink node is bigger than those farther away from sink node, the inner cluster heads(CHs) can reduce the energy consumption within a cluster and preserve more energy for inter-cluster data relaying. In addition to, the MAC and routing of networks are integrated to minimize the protocol overhead. The scheme of synchronization within a cluster can not only synchronize sleep schedule to ensure data deliveries among neighbor nodes but also avoid energy waste for following and maintaining unnecessary schedules. And the scheme of invitation is employed to make collision-free within a cluster, which can reduce the density of contending nodes and the collisions of traffic being probably temporal correlation. Simulation results show that EB-CLDG leads to more uniform energy dissipation and prolongs the lifetime of network than S-MAC.

Wireless sensor networks are a promising application of the Internet of Things in the sustainable development of smart cities, and have been afforded significant attention since first being proposed. Authentication protocols aim to protect the security and confidentiality of legitimate users when accessing and transmitting data. However, existing protocols may suffer from one or more security flaws. Recently, Butt et al. proposed an energy-efficient three-factor authentication protocol for wireless sensor networks. However, their protocol is vulnerable to several attacks, and lacks certain security properties. In this paper, the causes of these design flaws are analyzed. Furthermore, we propose a novel three-factor authentication protocol (password, smart card, and biometric information) for wireless sensor networks in Internet of Things contexts. A dynamic anonymous strategy is designed to prevent privacy disclosure and to resist sensor node capture attacks, tracking attacks, and desynchronization attacks. The Find–Guess model and random oracle model are combined to prove the security of the proposed protocol. A comparative analysis with related schemes shows that the proposed protocol has higher security and is able to maintain a low computational overhead.

Wireless sensor networks(WSN) are a kind of communication networks with in-dependent sensor nodes which could construct multi-hop ad hoc network to trans-fer data. The transport protocols for Wireless Sensor Network play an important role to promote the performance of the whole systems. This paper proposes a modified transport layer protocol for heterogeneous Wireless Sensor Networks(HWSN). As TCP is not suitable to use in HWSN directly, we design a modified transport protocol(named mTCP) based on TCP by a six-state finite state machine. Experimental results illustrate that our design can improve the communication capability of the transmission layer in heterogeneous wireless sensor networks significantly.

Wireless sensor networks congestion occurs easily due to its centralized traffic pattern. Normally, mono-sync wireless sensor network experiences multiple traffic flow congestion in the dense environment of the network, which leads to excess energy consumption and severe packet loss. To overcome these issues, a congestion detection and alleviation mechanism using cluster based heuristic optimized hierarchical routing protocol is proposed in this paper. Here, congestion detection and alleviation utilize the features of sensor nodes. The congestion is categorized into two types: (i) node level congestion and (ii) link level congestion. The node level congestion is detected by assessing the buffer utilization and the interval amid the consecutive data packets. The link level congestion is considered with computing link usage utilizing back-off step of round robin carrier sense multi-access with collision avoidance. Congestion detection and alleviation reactively affected node/link through cuckoo hosted rider search multi-hop routing algorithm. It has two phases: the cluster head selection and multi-path routing. Cluster head selection is performed through Taylor multiple random forest kernel fuzzy C-means clustering algorithm and multi-path routing is performed through cuckoo hosted rider search multi-hop routing algorithm. The simulation of the proposed method is done in network simulator tool. Here, the performance metrics, like packet delivery ratio, delay, energy consumption, packet drop, overhead, network lifetime and throughput are calculated. The experimental outcomes of the proposed technique shows 11.6%, 18.4% and 28.1% lower delay, 78.2%, 65.4% and 52.6% higher packet delivery ratio, and 29.2%, 37.4% and 40.8% lower packet drop compared with the existing methods, like congestion detection and alleviation using multi-attribute decision-making in optimization-based hybrid congestion alleviation routing protocol in wireless sensor networks, congestion detection and alleviation using hybrid K-means with greedy best first search algorithms in packet rate reduction utilizing adaptive weight firefly algorithm ant colony optimization based routing protocol in wireless sensor networks and congestion detection and alleviation using multi-input time on task optimization algorithm for altered gravitational search algorithm routing protocol in wireless sensor networks.

QoSNET: An integrated QoS network for routing protocols in large scale wireless sensor networks

Wireless sensor networks are a new emerging area where swarm intelligence can be applied with interesting implications. In fact, a strong analogy between unicellular organism colonies and wireless sensor networks can be emphasized: a sensor network can be viewed as a “colony” of simple, scarce resource nodes that, autonomously, are able only to perform simple tasks, but all together can accomplish very complex problems. In this paper we propose a routing protocol for multisink Wireless Sensor Networks with interesting properties: self organization, fault tolerance and environmental adaptation. The proposed protocol was inspired by the well known behavior (in artificial life studies) of “Slime Mold”. Such colony of unicellular organisms organizes itself in clusters by pheromone generation and evaporation mechanisms. In a similar manner our protocol manages the data traffic towards multiple sink nodes using the gradient concept and reaching high levels of autonomy and fault tolerance. We analyze the proposed protocol to examine the performances, the signalling overhead and the adaptation properties to environmental changes or nodes faults using simulation techniques.

In wireless sensor networks, MAC protocol is used to achieve efficient, fair and balanced allocation of wireless channel resources and access control of nodes in the network, and to control the communication process of nodes in the network. The energy consumption of wireless sensor nodes is mainly concentrated in the communication unit, including: data transceiver, idle listening, protocol control overhead, etc. A good MAC protocol is beneficial to reduce unnecessary energy consumption and enhance node life time. At the same time, MAC protocol, as the bottom protocol of wireless sensor network, provides a stable and reliable communication foundation for the realization of the upper protocol. Therefore, a large number of scholars at home and abroad have carried out extensive and in-depth research on MAC layer protocol of network. In this paper, the research process and progress of MAC layer protocol in wireless sensor networks are analyzed, and the research progress of MAC layer protocol in multi-radio frequency and multi-channel wireless sensor networks is analyzed.

The existing routing protocols for wireless sensor networks were not reasonable in design, which limited their application. Most of the existing studies did not take into account the energy consumption of the network and the balanced use of the energy of sensor nodes, which led to the unsatisfactory application effect of wireless sensor networks in some fields. Therefore, from the perspective of energy balance in wireless sensor networks, this paper proposed a construction method of an energy balance routing protocol in wireless sensor networks based on a fuzzy control strategy. Firstly, based on the analysis of the basic composition of wireless sensor networks and the structure of sensor nodes, this paper expounded the basic process of wireless data transmission and summarized the classification and characteristics of routing protocols in wireless sensor networks from different angles. Secondly, according to the node data transmission characteristics of wireless sensor networks, the energy balance use model of sensor nodes was established, and the design method of the energy balance routing protocol based on fuzzy control strategy was proposed, and the data transmission link was optimized. Finally, through experimental comparative analysis, the results showed that the energy balanced routing protocol proposed in this paper can effectively realize the energy balanced use of the network data transmission process. Compared with other common routing protocols, the wireless sensor network routing protocol proposed in this paper can not only improve the data transmission efficiency and reduce the data redundancy but also save energy consumption and prolong the network running time. The design method of routing protocol proposed in this paper will be conducive to the optimization and application of routing protocol in wireless sensor networks and provide a theoretical basis for the related research of wireless sensor networks.

Wireless Sensor Networks (WSNs) play a necessary position in todays actual world applications. WSNs are a team of autonomous sensor nodes that are geographically distributed to accumulate information and monitor events. WSNs are similarly sense that they rely on wireless connectivity and spontaneous formation of networks so that sensor information can be transported via wireless. Sometimes called dust network, minute sensors as small as dust referring to smart dust. WSNs are spatially distributed two to screen or bodily temperature, sound, pressure, etc. and to cooperatively ignore their data via the network to different locations. Each such sensor network node has typically various parts. Routing in WSNs in one of the important technique, because all node executes its battery power, if may be one node failure it collapse entire networks. Routing in WSNs is in reality difficult due to the intrinsic characteristics that differentiate these networks from different networks. The plan of routing protocols in WSN is affected via number of exigent factors. In this paper, a review on routing protocols for Wireless Sensor Networks (WSNs) and performance of its execution.

年图灵奖获得 者 Lamport 教授就指出时钟同步是分布式系统的关键依赖性条件 [4] .随着 21 世纪科学技术的高速发 展, 人们对网络化系统中分散时钟的有效同步提出了更高要求, 这正是因为网络化系统日益渗透到不 同行业

Clock synchronisation is an important requirement for various applications in wireless sensor networks (WSNs). Most of the existing clock synchronisation protocols for WSNs use some hierarchical structure that introduces an extra overhead due to the dynamic nature of WSNs. Besides, it is difficult to integrate these clock synchronisation protocols with sleep scheduling scheme, which is a major technique to conserve energy. In this paper, we propose a fully distributed peer–to–peer based clock synchronisation protocol, named Distributed Clock Synchronisation Protocol (DCSP), using a novel technique of pullback for complete sensor networks. The pullback technique ensures that synchronisation phases of any pair of clocks always overlap. We have derived an exact expression for a bound on maximum synchronisation error in the DCSP protocol, and simulation study verifies that it is indeed less than the computed upper bound. Experimental study using a few TelosB motes also verifies that the pullback occurs as predicted.

In monitoring wireless sensor networks (WSNs) with event-driven applications, the generated traffic usually has bursty characteristics when an event occurs. Transient congestion in the networks would increase delay and packet loss rate severely, reducing the network performance greatly. Through the analysis on delay and packet loss rate in congestion, this paper proposes a congestion-aware mac protocol (C-MAC) for wireless sensor networks. In C-MAC, backoff delay of the nodes around contention area is adopted as a congestion indication. In normal state, the CSMA/CA is working well at sensor nodes. And when the congestion occurs, localized TDMA replaces the CSMA/CA in the congestion nodes. With the above mechanism, the congestion nodes only deliver their data during its assigned slots to control the contention overhead. Finally, we implement the C-MAC in our sensor network testbed. The experiment results show that the proposed MAC protocol could effectively operate on the congestion caused by burst information, and reduce both the delay and packet loss rate significantly.

Wireless sensor networks (WSNs) have gained much attention in today’s research domain for supporting a wide variety of applications including the multimedia applications. Multimedia applications that are regarded as the quality-of-service (QoS)-aware, delay sensitive, and bandwidth hungry applications require enough energy and communication resources. WSNs being the energy-scarce network have now been designed in such a way that they can support these delay-sensitive and time-critical applications. In this paper, we propose an energy-efficient routing protocol for heterogeneous WSNs to support the delay sensitive, bandwidth hungry, time-critical, and QoS-aware applications. The proposed QoS-aware and heterogeneously clustered routing (QHCR) protocol not only conserves the energy in the network, but also provides the dedicated paths for the real-time and delay sensitive applications. The inclusion of different energy-levels for the heterogeneous WSNs also provides the stability in the networks while minimizing the delay for the delay-sensitive applications. Extensive simulations have been performed to validate the effectiveness of our proposed scheme. Our proposed routing scheme outperforms other state-of-the-art schemes in terms of the delay performances.

Clock synchronization is a crucial issue for data fusion, localization, duty cycle scheduling, and topology management in wireless sensor networks (WSNs). In this paper we proposed a cognitive global clock synchronization protocol (CGCSP) that is an accurate, energy efficient and reliable clock synchronization protocol in WSNs based on a single reference node. The CGCSP tackles the disadvantages of being single reference node by a cognitive switchover mechanism. This structure has been validated through the development of basic synchronization schemes i.e. sender-receiver (S-R) synchronization and receiver-receiver (R-R) synchronization. By evaluating and comparing the performances of it with state of the art protocols such as reference broadcast synchronization (RBS) and timing-sync protocol for sensor networks (TPSN), the proposed CGCSP shows reasonable lead over them in single hop network as well as in multi hop networks in terms of average synchronization accuracy and energy efficiency.

Due to miniaturization of hardware and availability of low-cost, low-power sensors, Wireless Sensor Network and Multimedia Sensor Network applications are increasing day by day. Each application has a specific quality of service and experience requirements. The design of routing and MAC protocol which can fulfill the requirements of the application is challenging given the constrained nature of these devices. Considerable efforts are directed towards the design of energy efficient QoS-aware routing protocols. In this article, we present state of the art review of routing protocols for Wireless Multimedia Sensor Networks while addressing the challenges and providing insight into research issues.