无线传感器网络环境下基于事件 驱动应用的节能TDMA协议

媒质接入控制是无线传感器网络设计的关键问题之一.由于媒质接入控制协议直接控制着节点无线通信模块的活动,而无线通信模块是传感器节点能量消耗的主要来源,因此MAC协议节能效率的好坏将严重影响网络的性能.基于TDMA的MAC协议具有固有的节能特性,即通过合理的TDMA调度避免传输碰撞以及减少节点空闲监听的时间.本文提出了ED-TDMA协议,一种面向事件驱动的传感器网络应用的TDMA协议.该协议根据当前源节点的数目动态地改变TDMA帧的长度,提高了信道利用率;同时采用位图方式的TDMA调度,极大地减少了TDMA调度的开销,节约了能量.此外,通过引入簇内覆盖的思想,使得簇内的活动节点数目为一常数,同时减少了工作节点的数目,从而延长网络的生命周期,并在一定程度上提高了系统的可伸缩性.实验结果显示,ED-TDMA协议更适用于网络负载较低、节点密度高的无线传感器网络.     

Algorithms to Minimize Data Transfer for Code Update on Wireless Sensor Network

In Wireless Sensor Networks, the preloaded program code and data on sensor nodes often need to be updated due to changes in user requirements and environmental conditions. Sensor nodes are severely restricted by energy constraints. It is especially energy consuming for sensor nodes to transfer data through wireless radios. To efficiently reprogram sensor nodes through radio, we propose an algorithm, Minimum Data transferred by Copying and Downloading (MDCD) and its extension E-MDCD, to minimize the number of bytes needed to be transferred from the host machine to the sensor nodes. Experimental results show that the E-MDCD algorithm reduces the number of bytes transferred by 93.25 % for small code change compared with the Rsync based algorithm. In average, E-MDCD can reduce 59.82 % compared with the existing the Rsync based algorithm and 16.14 % compared with the Vdelta algorithm.     

ON/OFF Markov Model Based Energy-Delay Aware MAC Protocol for Wireless Sensor Network

Today, the Wireless Sensor Networks (WSNs) are increasingly used in many applications, and in parallel the scientific researches to improve the features of such networks are accelerated. As the nodes are small components that suffer from very limited energy resources, several researches carried out at the MAC layer in order to minimize energy costs. The techniques based on periodic active/passive mode are energy efficient, but the node can not adapt the behavior of the transceiver according to the network traffic. Our approach aims to reduce the latency without increasing energy consumption. We propose to manage the radio in a dynamic way according to ON/OFF Markov model. The passage from passive to active mode is set according to the transition probability from OFF to ON state. Based on this probability, we give the period that the transceiver can stay in sleep mode. Through simulation we show that the proposed technique outperforms the well known MAC protocol for WSN.     

Diagnosis of Wireless Sensor Networks in Presence of Permanent and Intermittent Faults

In this paper we consider the problem of distributed fault diagnosis in Wireless Sensor Networks (WSNs). The proposed Fault Diagnosis Algorithm (FDA) aims to handle both permanent and intermittent faults. The sensor nodes with permanent communication faults can be diagnosed by using the conventional time-out mechanism. In contrast, it is difficult to detect intermittent faults due to their inherent unpredictable behavior. The FDA is based on the comparison of sensor measurements and residual energy values of neighboring sensor nodes, exploiting their spatial correlations. To handle intermittent faults, the comparisons are made for \(r\) rounds. Two special cases of intermittent faults are considered: one, when an intermittently faulty node sends similar sensor measurement and similar residual energy value to some of its neighbors in all \(r\) rounds; another, when it sends these values, either or both of which deviates significantly from that of some neighbors in all \(r\) rounds. Through extensive simulation and analysis, the proposed scheme is proved to be correct, complete, and efficient to handle intermittent faults and hence, well suited for WSNs.     

IPool-ADELIN: An extended ADELIN based on IPool node for reliable transport of Underwater Acoustic Sensor Networks

ADELIN (ADaptive rELIable traNsport) protocol is a reliable transport protocol only based on FEC (Forward Error Correction) for UASN (Underwater Acoustic Sensor Networks). In cooperative scenario, ADELIN improves its reliability of data packet transmission further by forwarding node redundancy, which wastes the limited energy and bandwidth of nodes. In this paper, the IPool-ADELIN protocol is proposed and shown to help reduce energy consumption. In IPool-ADELIN, by overhearing the data transmissions, the IPool node not only relays the data packets, which are not implicitly acknowledged, but also does local link maintenance when the BER (Bit Error Rate) of the monitored link is high. The results of mathematical analysis and simulations show that IPool-ADELIN has a higher data delivery ratio and lower energy consumption.     

无线传感器网络中利用随机网络编码的低能耗可靠机会路由

无线传感器网络中节点大多采用电池供电,让节点以低能耗将采集的数据传递到信宿,对无线传感器网络有效运行极为重要.该文提出了能量有效的可靠机会路由EROR（Energy-efficient Reliable Opportunistic Routing）,它利用结合节点剩余能量和链路上收发双方的总能耗的转发代价,选择转发节点集合（简称“转发集”）、主转发节点和协助转发节点,让节点调节发射功率并利用随机线性编码把数据包分片编码发送到转发集,进而以多跳方式把数据可靠低能耗地传递到信宿.仿真结果表明：在网络生存时间和能耗方面,EROR比已有路由策略CodePower更优.     

Collision avoidance slot allocation scheme for multi-cluster wireless sensor networks

This paper introduces a collision avoidance slot allocation scheme for Time Division Multiple Access (TDMA) based Medium Access Control (MAC) in multi-cluster wireless sensor networks. TDMA MAC protocols have built-in active-sleep duty cycle that can be leveraged for limiting idle listening. Also, they can overcome the overhearing problem, thus have better energy efficiency. Enabling concurrent intra-cluster communications using a single radio channel is a key issue in TDMA MAC protocols. Using orthogonal frequency channels or different Code Division Multiple Access codes for different adjacent clusters can solve the problem at the expense of cost. In this paper, we propose a new distributed slot allocation protocol called  Coordinated   Time   Slot   Allocation (CTSA) that can reduce collisions significantly using a single radio channel. We use simulations to study the effects of different system parameters on the performance of our proposed protocol. Simulation results show that applying CTSA over clustering protocols can significantly reduce collisions. It also shows fast convergence for our proposed CTSA protocol. In this paper we apply our CTSA scheme to the Low Energy Adaptive Clustering Hierarchy protocol which forms the basis for many cluster based routing protocols. CTSA is also compared with the SRSA algorithm proposed by Wu and Biswas (Wirel Netw 13(5):691–703, 2007) by means of simulation.     

Dynamic clustering approach based on wireless sensor networks genetic algorithm for IoT applications

Energy is vital parameter for communication in Internet of Things (IoT) applications via Wireless Sensor Networks (WSN). Genetic algorithms with dynamic clustering approach are supposed to be very effective technique in conserving energy during the process of network planning and designing for IoT. Dynamic clustering recognizes the cluster head (CH) with higher energy for the data transmission in the network. In this paper, various applications, like smart transportation, smart grid, and smart cities, are discussed to establish that implementation of dynamic clustering computing-based IoT can support real-world applications in an efficient way. In the proposed approach, the dynamic clustering-based methodology and frame relay nodes (RN) are improved to elect the most preferred sensor node (SN) amidst the nodes in cluster. For this purpose, a Genetic Analysis approach is used. The simulations demonstrate that the proposed technique overcomes the dynamic clustering relay node (DCRN) clustering algorithm in terms of slot utilization, throughput and standard deviation in data transmission.

     

Trusted Neighbors Based Secured Routing Scheme in Wireless Sensor Networks Using Agents

In Wireless Sensor Network (WSN) applications, nodes are deployed in public domains that are prone to be attacked by various types of attacks wherein the data confidentiality, integrity and authentication are compromised. In this paper, we propose Agent based SEcured Routing using Trusted neighbors (ASERT) in WSN. ASERT selects trustworthy neighbors and establishes secured routes using software agents. ASERT operates in following phases. (1) Defining Safeguard Agency (SA) and Routing Agency (RA), both consisting of static and mobile agents and a knowledge base. (2) Identification of trustworthy neighbor nodes by SA with trust model that consists of probability and Message Authentication Codes (MAC) model. (3) Probability model estimates the trustworthy channel and trustworthy nodes whereas MAC model ensures them. (4) MAC’s are dynamically computed by agents by generating the keys with the help of Random Oracle Extractor (ROE). (5) RA establishes secured routes from source to the sink node using agents. (6) Agents effectively identify possible security threats on wireless channel and node. (7) An improvement in packet delivery ratio, packet delivery latency, route maintenance overhead, memory overhead and energy consumption is achieved in ASERT as compared to two protocols, namely, Bio-inspired Trust and Reputation model in WSN (BTRM-WSN) using ant colony based approach and Ambient Trust Sensor Routing that uses trust combined with location information for routing.     

SEPFL routing protocol based on fuzzy logic control to extend the lifetime and throughput of the wireless sensor network

In this paper a new protocol using fuzzy logic control has been proposed. The protocol is based on Stable Election Protocol (SEP). Fuzzy logic control based on three variables, distance of nodes form base station, density of nodes and the battery level of nodes along with the traditional threshold values used in SEP are used to enhance the process of cluster head election in the existing SEP protocol and improve the lifetime and throughput of the Wireless Sensor Network. The result of the simulation which has been done in MATLAB simulator indicates that Stable Election Protocol based on fuzzy logic is more energy efficient and improves the lifetime and throughput of the network by 73.2 and 68.54 % respectively comparing with the existing SEP protocol.     

MIMO链路Ad Hoc网络中线程化的拓扑未知多址接入协议

针对MIMO链路Ad Hoc网络,提出了支持MIMO的线程化拓扑未知多址接入协议(MIMO-T-TTMA).MIMO-T-TTMA将时间扩展多址接入(TSMA)协议和时分多址接入(TDMA)协议以时间交替的方式相结合,进而为网络中节点分配时隙.在MIMO-T-TTMA中,每个节点被分配了若干时隙,每个分配时隙中,节点通过交互请求发送/允许发送(RTS/CTS)分组来确定发送使用的数据流数,而当RTS/CTS交互失败或者当前时隙为未分配时隙时,节点仍依一定的概率发送一个数据流,以提高网络的吞吐量.为了评估协议的性能,推导了MIMO-T-TTMA的吞吐量.数值结果表明,与已有的协议相比,MIMO-T-TTMA在节点度较大时具有较高的吞吐量,并且,吞吐量随节点度的变化比较平稳,因此,MIMO-T-TTMA适用于拓扑常发生剧烈变化的Ad Hoc网络.     

Two Tier Cluster Based Data Aggregation (TTCDA) for Efficient Bandwidth Utilization in Wireless Sensor Network

Wireless Sensor Networks are often used for monitoring and control applications where sensor nodes collect data and send it to the sink. Direct transmission of data packets to the sink from nodes in the network causes increased communication costs in terms of energy, network lifetime and bandwidth utilization. In this context, this paper proposes Two Tier Cluster-based Data Aggregation (TTCDA) algorithm for the randomly distributed nodes in the network to minimize computation and communication cost. The TTCDA effectively considers the packet and data aggregation using additive and divisible aggregation functions at cluster head and sink. The aggregation functions are applied according to spatial and temporal correlation of packets and data generated by each node. It also prevents transmission of redundant data by improving energy consumption and bandwidth utilization as compared with state-of-the-art solution. The performance of the algorithm is validated using examples and simulations. Also, it is seen that packet aggregation in TTCDA is better for the bandwidth utilization as it reduces average energy consumption by 3.13 % as compared to data aggregation.     

A sub-nanosecond Synchronized MAC – PHY cross-layer design for Wireless Sensor Networks

In this paper, we present a Wireless Sensor node implementation which aims at solving two major issues in Wireless Sensor Networks. This solution provides nanosecond-scale synchronization between nodes and high data-rate transmission thanks to cross-layer design and the time-domain properties of UltraWide Band (UWB) modulation schemes. The high data rate is achieved through a specific implementation of a IR-UWB physical layer. Specific algorithms are also implanted into the MAC and physical layers and form a cross-layered synchronization protocol for deterministic Wireless Sensor Networks named WiDeCS (Wireless Deterministic Clock Synchronization). This protocol propagates master time reference to nodes of a cluster tree network. WiDeCS Cross layered scheme is possible thanks to flag signals rising in the physical layer. These signals, owing to the UWB time domain properties, capture precise timestamps of transmission and reception. Hardware level simulations show a clock synchronization precision of 2 ns with a 2 GHz bandwidth signal, and an ASIC demonstrator shows 374 ps synchronization precision and 677 ps of standard deviation with the same bandwidth. In this paper, the physical layer implementation is detailed, and the cross-layered WiDeCS scheme is demonstrated.     

Throughput analysis for interference limited TDMA and TDMA/CDMA wireless ad hoc networks

The node throughput, which is defined as the total rate received at each node, is evaluated for the interference limited TDMA and TDMA/CDMA wireless ad hoc networks. In the TDMA wireless ad hoc network, there is only one transmission link connected to each node in the same time slot, whereas in the TDMA/CDMA wireless ad hoc network there are multiple transmission links connected to each node in the same time slot. We first derive the node throughput for these two wireless ad hoc networks and then make a comparison of the node throughput between them. The theoretical results and simulation results both reveal that the TDMA wireless ad hoc network outperforms the TDMA/CDMA wireless ad hoc network in the node throughput. Copyright © 2008 John Wiley & Sons, Ltd.     

A Dynamic Backup Path Management Method for TDMA Based WiMAX Client WMNs

This paper proposes a backup path management method for time division multiple access (TDMA) based client wireless mesh networks (WMNs). In a TDMA based client WMN, as links/nodes fail or as nodes perform handover and as flows enter and leave the network, the paths between various nodes change as well as the bandwidth available along these paths. In these networks, to support the quality of service requirements of flows, backup paths with the required bandwidth need to be established dynamically. Some methods are proposed in the literature to establish backup paths which handle link/node failures and node handover in ad hoc networks, but none of these methods can provide backup paths with the required bandwidth dynamically. To address that issue, the present paper proposes a backup path management method which is adaptive to both topological changes and traffic changes in a network. Each node along the current path between a source and a destination finds backup paths with the required bandwidth in order to handle failure of the link to its downstream node and its own failure or handover. Nodes use two-hop neighborhood information and slots status information of two-hop neighbors to establish backup paths. We prove that the number of backup paths available when a node N searches for backup paths to handle its own failure are more than the number of backup paths available when some other node searches for the backup paths for the failure of node N. Performance of the proposed method is compared with the performance of a naive path management (NPM) method in which always the source establishes backup paths whenever a link/node fails or a node performs handover, and also with the performance of a backup path management method proposed in the literature. The proposed method significantly outperforms the NPM method and the method selected from the literature. For example, when the speed of the mobile nodes is 50 m/s, the packet delivery ratio with the proposed method is 63 % more than the NPM method and 35 % more than the method selected from the literature.     

Low end‐to‐end delay fuzzy networking protocol for mobile wireless sensing

Because of the practical limitations of the energy and processing capabilities, the deployment of many Wireless Sensor Networks (WSN) is facing two main challenges of increasing network lifetime and reducing End to End Delay (EED) which become critical when the nodes are mobile and use non‐rechargeable energy sources. One way to help to extend network lifetime is using fuzzy logic in a form of artificial intelligence. To this end we propose a new routing protocol for using mobile WSNs, which holds the nodes in an equal level of energy and decreases energy dissipation of the network. An optimum path is selected based on the cost of each node to increase network lifetime. In order to lessen EED, we also attempt to design a novel zoning‐scheme for the network area. In this scheme, zonation is dynamic and works based on the Data Link (DL) position. The simulation result shows a significant improvement in lifetime and EED by proposed protocol compared with existing protocols. Copyright © 2016 John Wiley & Sons, Ltd.     

Efficient Patient Care Through Wireless Body Area Networks—Enhanced Technique for Handling Emergency Situations with Better Quality of Service

Wireless body area networks (WBAN) is a wireless network of sensors placed in and around the human body for monitoring the patient conditions remotely. The goal of WBAN networks is to report the patient condition to the monitoring system with maximum reliability and minimum delay and deliver the life critical data in the emergency situation with utmost priority. The proposed MAC protocol is aimed at delivery of emergency packets with maximum reliability and minimum delay through the introduction of mini slots in the beacon enabled superframe for exclusive transmission of the same. To improve the packet delivery ratio of the normal packets and decrease the energy consumption of the low data rate nodes, a packet rate based scheduled slot allocation is added to this protocol. Extensive simulations show that the proposed protocol is able to achieve nearly 98% packet delivery ratio and less than 100 ms delay for emergency packets. By varying the number of allocated scheduled slots based on the packet rate of the nodes, the proposed protocol has shown improved performance in the packet delivery ratio (93%) of normal packets as compared to IEEE 802.15.6 (85%), also the energy consumption of low data rate nodes has decreased by 64%. The results show that the proposed protocol is successful in realizing much better delay and packet delivery values for emergency and normal packets.     

基于运动预测的水下传感器网络MAC协议

 在海洋环境的影响下,水下无线传感器网络(UWSN)节点始终处于运动状态;UWSN采用声信号通信,缓慢的节点移动也会造成UWSN现有的多址接入技术(MAC)协议冲突避免机制失效。该文建立了水下节点的运动模型,基于AR运动预测模型减小水下节点的时空不确定性对于MAC协议的影响,提高发送信息在预约时隙到达的概率。仿真结果表明,采用AR(5)预测可以减小74.8%的时延探测误差。提出了基于预测的预约MAC协议：P-MAC。NS-2仿真结果表明该协议在海浪运动场景下能提高收包成功率(PRR)10%-15%。     

一种利用信道侦听的动态TDMA协议

针对TDMA网络节点间业务量不均匀时,会造成信道资源严重浪费的情况,提出了一种利用信道侦听的CS-TDMA协议。该协议在TDMA协议的基础上,节点通过接收到各节点的数据包数量估算相应节点的业务量大小。当某节点时隙剩余时,向其统计中业务量最大的一个节点发送ATS信息,通知该节点占用剩余时隙发送数据,直至时隙结束。仿真结果表明,CS-TDMA协议较TDMA协议在传输时延、吞吐量、数据接收率上均有所提高,尤其在节点间业务量大小不均匀时,时延性能提升更加明显。     

Toward In-Band Self-Organization in Energy-Efficient MAC Protocols for Sensor Networks

This paper presents a self-organizing medium access control (MAC) protocol framework for distributed sensor networks with arbitrary mesh topologies. The novelty of the proposed In-band self-organized MAC (ISOMAC) protocol lies in its in-band control mechanism for exchanging time-division multiple access (TDMA) slot information with distributed MAC scheduling. A fixed-length bitmap vector is used in each packet header for exchanging relative slot timing information across immediate and up to two-hop neighbors. It is shown that, by avoiding explicit timing information exchange, ISOMAC can work without networkwide time synchronization, which can be prohibitive for severely cost-constrained sensor nodes in very large networks. A slot-clustering effect, caused by in-band bitmap constraints, enables ISOMAC to offer better spatial channel reuse compared to traditional distributed TDMA protocols. ISOMAC employs a partial node wake-up and header-only transmission strategy to adjust energy expenditure based on the instantaneous nodal data rate. Both analytical and simulation models have been developed for characterizing the proposed protocol. Results demonstrate that, with in-band bitmap vectors of moderate length, ISOMAC converges reasonably quickly, that is, approximately within a four to eight TDMA frame duration. Also, if the bitmap header duration is restricted within 10 percent of packet duration, then the energy penalty of the in-band information is quite negligible. It is also shown that ISOMAC can be implemented in the presence of network time synchronization, although its performance without synchronization is just marginally worse than that with synchronization.