Applied Mechanics and Materials Vols. 303-306

Abstract: Localization technology is one of the key supporting technologies in wireless sensor networks. In this paper, a collaborative multilateral localization algorithm is proposed to localization issues for wireless sensor networks. The algorithm applies anchor nodes within two hops to localize unknown nodes, and uses Nelder-Mead simplex optimization method to compute coordinates of the unknown nodes. If an unknown node can not be localized through two-hop anchor nodes, it is localized by anchor nodes and localized nodes within two hops through auxiliary iterative localization method. Simulation results show that the localization accuracy of this algorithm is very good, even in larger range errors.

Abstract: In this paper we present a low-power, low-latency MAC protocol adequate for critical data transmission. For support critical data packet transmission the proposed MAC protocol uses the modified IEEE 802.15.4 beacon frames including priority bit, sender node address, and NAV value fields. A receiver node periodically wakes up, receives sender beacon frames from its neighbor nodes, selects a data sending node, and broadcasts a beacon frame containing the selected sender’s address. Based on the sender’s data transmission urgency, a receiver node selects a data packet sending node. So critical data packet will be considered higher priority packet and be sent preferentially. Our simulations and analytical analysis have shown that our protocol outperforms other protocols in terms of energy consumption and higher priority packet delivery delay.

Abstract: The cognitive radio technology has been adopted as a promised solution to deal with overcrowded problem in ISM band. In wireless sensor networks, the cognitive radio technology enables sensor nodes to occupy licensed band in opportunistic manner and introduces advantages of improving spectrum utilization and increasing system throughput. By considering the opportunistic spectrum access nature, in this paper, we aim to provide a stable path selection scheme for cognitive radio sensor networks. The proposed routing protocol utilizes priori delivery information and derives a novel routing metric for the optimal path selection. The routing metric is derived from naïve Bayes inference and used to indicate the path stability by means of delivery probability. We show through extensive simulations that the proposed routing protocol is efficient to find the most probable delivery path and increase the system throughput.

Abstract: The Implementation of microenvironment monitoring system in network for greenhouse is based on the agricultural greenhouse micro environment and combined with wireless sensor network technology. Information is received by the sensors in the front system with the parameters such as temperature, humidity, light and carbon dioxide. the sensor signal acquisition and A/D conversion is controlled by the processor module which is also the controller of the WiFi wireless module. Wireless router relay communication enlarging the monitoring area is used in the system design. The communication between the terminal nodes and the monitoring center and a series of process like data collecting, processing, transmitting and displaying are all controlled by software. The system has the benefits of networking quick and easy, stable operation, good extension and low power consumption, and it can meet the needs of the micro environment measurement and control system.

Abstract: Underwater sensor network (UWSN) adopts acoustic communication and is characterized by high delay, low bandwidth, high error rate, low energy-consumption requirement and sparse topology, which lead to conventional network protocols for terrestrial WSN or other wireless multi-hop networks are unable to satisfy the performance of UWSN. On the other hand, the limited resources of energy, CPU and memory cause that the protocol stack running on the sensor node shouldn’t be much complicated. The paper proposes a novel, green network protocol architecture model tailored for UWSN, referred to as Micro-ANP, which is three layered structure including application, network transport, and physical layer. Furthermore, basing on Micro-ANP we realize the packet size optimization of UWSN through Matlab simulation. Micro-ANP protocol architecture and packet size optimization improve the energy efficiency of UWSN, prolong the network lifetime and achieve green network while meeting the requirement of QoS with the constraints of limited resource.

Abstract: the cause of the routing void of the WSN is analyzed,then the energy consumption model is established to analyze the optimal number of hops and a new routing protocol model based on energy balance is established. through simulation of the networks, it can be seen that the improved routing protocol can extend the lifetime of WSN.

Abstract: The characteristics and environment of the underwater acoustic (UWA) sensor network require a MAC protocol to be suitable for the long propagation delay. So we put forward a suitable MAC protocol, referring to the AGENT protocol in this paper. We call this protocol C-AGENT-LPD, which means C-AGENT with Long Propagation Delay. And it makes full use of the spatial multiplexing of the UWA channel. Through the simulations, we can see that the protocol has better time delay and throughput performance than the other two MAC protocols.

Abstract: In the LEAP (Localized Encryption and Authentication Protocol), disclosure of the initial key will threaten the security of the entire network. B.Tian and his fellows improved the LEAP and diminished the threat. They reduced the number of exposed communication keys resulted from the disclosure of the initial key. In this paper, we show the deficiency of the improved protocol put forward by B.Tian et al and propose a new key management protocol for multiphase hierarchical WSN (NPMHW) . NPMHW designs a special method to establish the key ring by using random numbers and the HASH function. It also introduces a mechanism to detect whether the node is captured or not. Analysis indicates that, compared with B.Tian’s protocol, NPMHW localized the threat and greatly reduced the number of the exposed communication keys caused by the disclosure of the initial key. Therefore, the protocol raised in this paper is much safer.

Abstract: With the constant development of wireless sensor networks technology, the expanding application scope and the increasing processing power of sensor nodes, there are more and more data collected and processed through the sensor, thus ensuring the security of information transmission between nodes is in urgent needs. The secure application of wireless sensor networks has become a hot technology. This paper mainly expounds the key management schemes of wireless sensor networks, and analyzes the mainstream key management schemes.

Abstract: There are large number of mechanical, electrical and auxiliary devices, and many sensors and intelligent nodes in urban train. The coupling relationship among onboard nodes becomes more and more complex, and various safety detection and information system demand train communication network higher performance. All of these variations need security detection sensor network which has high real-time, bandwidth and interoperability, good maintainability and expansibility. As the existing train communication network transmission rate is low, large capacity status and fault diagnosis data, the event log data, audio and video data which are stored in different vehicles equipments, and cannot be efficient and timely processing. So, it is difficult to realize the information transmission and processing, fault diagnosis and intelligent maintenance of train set. Based on the train level and vehicle level Ethernet network, this paper will focus on network construction technology of large volume onboard security detection sensor network. The research results will help to improve performance of urban train.