Energy efficient and QoS based routing protocol for wireless sensor networks

The increasing demand for real-time applications in Wireless Sensor Networks (WSNs) has made the Quality of Service (QoS) based communication protocols an interesting and hot research topic. Satisfying Quality of Service (QoS) requirements (e.g. bandwidth and delay constraints) for the different QoS based applications of WSNs raises significant challenges. More precisely, the networking protocols need to cope up with energy constraints, while providing precise QoS guarantee. Therefore, enabling QoS applications in sensor networks requires energy and QoS awareness in different layers of the protocol stack. In many of these applications (such as multimedia applications, or real-time and mission critical applications), the network traffic is mixed of delay sensitive and delay tolerant traffic. Hence, QoS routing becomes an important issue. In this paper, we propose an Energy Efficient and QoS aware multipath routing protocol (abbreviated shortly as EQSR) that maximizes the network lifetime through balancing energy consumption across multiple nodes, uses the concept of service differentiation to allow delay sensitive traffic to reach the sink node within an acceptable delay, reduces the end to end delay through spreading out the traffic across multiple paths, and increases the throughput through introducing data redundancy. EQSR uses the residual energy, node available buffer size, and Signal-to-Noise Ratio (SNR) to predict the best next hop through the paths construction phase. Based on the concept of service differentiation, EQSR protocol employs a queuing model to handle both real-time and non-real-time traffic.     

An efficient Dynamic Addressing based routing protocol for Underwater Wireless Sensor Networks

Underwater Wireless Sensor Networks (UWSNs) are different in many aspects as compared to terrestrial sensor networks. Other than long propagation delays and high error probability, continuous node movement makes it hard to manage the location information of sensor nodes. Determining the location of every node is a major issue as nodes can move continuously with the water currents. In order to handle the problem of large propagation delays and unreliable link quality, many algorithms have been proposed and some of them provide good solutions for these issues, but continuous node movements still need attention. In order to handle the problem of node mobility, we proposed a Hop-by-Hop Dynamic Addressing Based (H2-DAB) routing protocol, where every node in the network will be assigned a routable address in a quick and efficient way without requiring an explicit configuration or any dimensional location information. It helps to provide an option where nodes can communicate without any centralized infrastructure, also a mechanism is available where nodes can come and leave the network without having any serious effect on the rest of the network. Simulation results show that H2-DAB can manage easily during the quick routing changes where node movements are very frequent yet require little or no overhead in order to complete its tasks.     

无线传感器网络的QoS体系结构

不同于传统互联网,作为涵盖了数据感知、处理和传输的复杂任务型网络,无线传感器网络面向应用的特点给服务质量(QoS)研究带来了许多新的挑战,需要针对QoS体系结构以及QoS指标间复杂关系的系统工作.文中首先提出了无线传感器网络中QoS指标的分层模型以及相应的规范化描述,然后分析了QoS指标的映射关系,最后提出了一个层次化的QpS体系结构,希望为无线传感器网络中QoS保障技术的系统性研究提供参考.     

A reliable QoS aware routing protocol with slot assignment for mobile ad hoc networks

A mobile ad hoc network (MANET) is a collection of mobile hosts that form a temporary network on the fly without using any fixed infrastructure. Recently, the explosive growth in the use of real-time applications on mobile devices has resulted in new challenges to the design of protocols for MANETs. Chief among these challenges to enable real-time applications for MANETs is incorporating support for quality of service (QoS), such as bandwidth constraints. However, MANETs having a high ratio of topology change make routing especially unstable; making stability is an important challenge, especially for routing having a quality of service provision. In this paper, we propose a reliable multi-path QoS routing (RMQR) protocol with a slot assignment scheme. In this scheme, we examine the QoS routing problem associated with searching for a reliable multi-path (or uni-path) QoS route from a source node to a destination node in a MANET. This route must also satisfy certain bandwidth requirements. We determine the route expiration time between two connected mobile nodes using global positioning system (GPS). Then, two parameters, the route expiration time and the number of hops, are used to select a routing path with low latency and high stability. Simulation results show that the proposed RMQR protocol have some outstanding properties when compared with Lin's [Lin C-R. On-demand QoS routing in multihop mobile networks. In: Proceedings of the twentieth annual joint conference of the IEEE computer and communications societies (INFOCOM), vol. 3(22–26), 2001, p. 1735–44], Liao's [Liao W-H, Tseng Y-C, Wang S-L, Sheu J-P. A multi-path QoS routing protocol in a wireless mobile Ad Hoc network. Telecommunication Systems 2002;19(3–4):329–47], and Chen's [Chen Y-S, Tseng Y-C, Sheu J-P, Kuo P-H. An on-demand, link-state, multi-path QoS routing in a wireless mobile Ad-Hoc network. Computer Communications 204;27(1):27–40] protocols.     

基于蚁群算法的能量有效的传感器网络可靠路由协议

针对传统的多路径方法在网络生存时间方面表现的不足,提出了一种基于蚁群算法的新方法.该方法在路径选择时不仅考虑了路径的最优性也即最小跳数,而且还把节点的剩余能量作为路径选择的依据.在发送数据时,基于概率选择其中的一条路径,避免始终使用一条路径传送数据以防止该路径上的节点能量耗尽,网络中各节点比较均衡地消耗能量.因此,该方法有效的延长了网络生存时间.最后,基于TOSSIM的仿真结果表明,该方法与已有的不相交多路径方法和缠绕方法相比,网络可靠性较高,网络生存时间较长.     

A mobility aware protocol synthesis for efficient routing in ad hoc mobile networks

In mobile ad hoc networks (MANETs), the mobility of the nodes is a complicating factor that significantly affects the effectiveness and performance of the routing protocols. Our work builds upon recent results on the effect of node mobility on the performance of available routing strategies (i.e., path-based, using support) and proposes a protocol framework that exploits the usually different mobility rates of the nodes by adapting the routing strategy during execution. We introduce a metric for the relative mobility of the nodes, according to which the nodes are classified into mobility classes. These mobility classes determine, for any pair of origin and destination, the routing technique that best corresponds to their mobility properties. Moreover, special care is taken for nodes remaining almost stationary or moving with high (relative) speeds. Our key design goal is to limit the necessary implementation changes required to incorporate existing routing protocols into our framework. We provide extensive evaluation of the proposed framework, using a well-known simulator (NS2). Our first findings demonstrate that the proposed framework improves, in certain cases, the performance of existing routing protocols.     

An efficient bow-based on-demand QoS routing protocol for MIMO ad hoc networks

The multiple inputs multiple output (MIMO) architecture supports smart antennas and MIMO links is now a popular technique for exploiting the multi-path, spatial multiplexing, and diversity gain to provide high spectral efficiencies and performance improvement in wireless ad hoc networks. In this work, we propose a new multi-path on demand quality-of-service (QoS) routing architecture, looked like a bow and called as bow structure, in MIMO ad hoc networks. A bow-based MIMO ad hoc networks routing protocol, named as BowQR, is also proposed to support QoS requirement and to improve the transmission efficiency. Each bow structure is composed of rate-links and/or range-links on demand to provide multi-path routing and satisfy the bandwidth requirement. Two types of transmission links, the rate-link and range-link, exploit the spatial multiplexing and spatial diversity to provide extremely high spectral efficiencies and increase the transmission range. Finally, the simulation results show that our BowQR protocol achieves the performance improvements in throughput, success rate, and average latency.     

利用能效优化的WSN自组织位置感知协议

针对无线传感器网络存在能耗和投递率等约束问题,提出了一种利用能效优化的自组织位置感知协议(EESLP).首先,根据主干锚节点的位置感知将网络构建成树结构;然后,利用拓扑控制优化网络的拓扑结构来维持网络的连通性和覆盖范围;接着,在路径选择过程中加入节能机制,均衡网络负载;最后,利用自组织方式最小化消息传输和接收次数,降低消息复杂度,减少协议开销.仿真实验结果表明,该协议具有良好的能量效率,相比其他几种能量感知协议,该协议具有更高的包投递率和更低的能耗,有效延长了网络寿命.     

一种基于模糊逻辑与状态感知的MANET路由协议

移动自组网络(MANET)是一种多跳无中心自组无线网络,其中,负载和能量是2个重要的路由优化指标。由于在路由过程中它们会动态变化,所以,很难用具体数值完整描述。为此,引入模糊集与模糊逻辑的思想,提出了一种基于模糊逻辑与状态感知的路由协议(FLSAR),给出结合负载和能量的综合路由指标,使整个网络中负载和能量能更均匀地分布。NS2仿真结果表明:本协议能较好地提高吞吐量和延长网络生存时间。     

无线传感器网络能量自调Q路由算法

无线传感器是一种非常微小、精密的,内嵌微处理器的设备,其特点在于当传感器在区域内布点后,这些节点不能再充电;所以在无线传感器网络设计中,能量的开销及网络负载平衡是首先应考虑的因素.提出了一种能量自调式Q路由算法(Q routing with energy and position awareness).使用开放的模拟器OMNET ,比较了QREA协议与传统的路由协议一完全位置路由(geographical routing)的性能.通过实验得出了一个近优化的路由模型.     

无线传感器网络S-MAC协议的改进

在无线传感器网络中,基于竞争的S-MAC协议存在无法使节点的活动时间根据通信负载动态变化以及节点休眠带来的延迟问题.本文结合T-MAC协议和D-MAC协议,提出了自己针对这些问题的改进方法.仿真结果证明,提出的改进方法不仅能够使节点的活动时间适应通信负载的动态变化,还能够极大地减少节点休眠带来的延迟.     

基于事件区域的无线传感器网络能量感知路由

根据无线传感器网络实际应用特点,提出了事件区域传输模型.并在该模型上提出一种能量感知路由ABEA(Event-Area Based Energy Aware Routing).ABEA在事件区域的边缘选择一个能量较高的节点作为根节点,事件区域内的其它源节点以这个节点为根,以跳数和节点剩余能量为权值形成一个数据融合树.根节点将事件区域内片断数据融合计算生成事件信息,事件信息沿着能量感知的路径传送到Sink节点.仿真结果表明,ABEA具有较小的能量消耗及传输延时,并使网络能量消耗均衡.     

Wireless Sensor Network transport protocol: A critical review

The transport protocols for Wireless Sensor Network (WSN) play vital role in achieving the high performance together with longevity of the network. The researchers are continuously contributing in developing new transport layer protocols based on different principles and architectures enabling different combinations of technical features. The uniqueness of each new protocol more or less lies in these functional features, which can be commonly classified based on their proficiencies in fulfilling congestion control, reliability support, and prioritization. The performance of these protocols has been evaluated using dissimilar set of experimental/simulation parameters, thus there is no well defined benchmark for experimental/simulation settings. The researchers working in this area have to compare the performance of the new protocol with the existing protocols to prove that new protocol is better. However, one of the major challenges faced by the researchers is investigating the performance of all the existing protocols, which have been tested in different simulation environments. This leads the significance of having a well-defined benchmark for the experimental/simulation settings. If the future researchers simulate their protocols according to a standard set of simulation/experimental settings, the performance of those protocols can be directly compared with each other just using the published simulation results. This article offers a twofold contribution to support researchers working in the area of WSN transport protocol design. First, we extensively review the technical features of existing transport protocols and suggest a generic framework for a WSN transport protocol, which offers a strong groundwork for the new researchers to identify the open research issues. Second we analyse the experimental settings, focused application areas and the addressed performance criteria of existing protocols; thus suggest a benchmark of experimental/simulation settings for evaluating prospective transport protocols.     

Group-Based Trust Management Scheme for Clustered Wireless Sensor Networks

Traditional trust management schemes developed for wired and wireless ad hoc networks are not well suited for sensor networks due to their higher consumption of resources such as memory and power. In this work, we propose a new lightweight group-based trust management scheme (GTMS) for wireless sensor networks, which employs clustering. Our approach reduces the cost of trust evaluation. Also, theoretical as well as simulation results show that our scheme demands less memory, energy, and communication overheads as compared to the current state-of-the-art trust management schemes and it is more suitable for large-scale sensor networks. Furthermore, GTMS also enables us to detect and prevent malicious, selfish, and faulty nodes.     

无线传感器网络的安全分簇路由协议

在无线传感器网络(WSN)中,安全问题已经成为一个重要的问题.但在现有的WSN路由协议中,很多仅考虑节能因素而没考虑安全因素,而那些专门为安全而设计的路由协议则一般开销较大算法复杂,难以在WSN中实施.为解决问题,提出了一种安全节能的分簇路由协议SEEC,它综合了安全高效的SEER路由协议以及基于剩余能量的非均匀分簇路由协议两者的优点:节点仅仅需要完成数据传感等简单功能.而由基站完全控制簇的管理和路由选择,不仅节约了节点能量,而且防止了恶意节点的攻击;另外,对节点的非均匀分簇,更进一步节约了能量.分析和仿真结果表明,方案不仅能够提供很好的安全性,而且有效地延长了网络生存时间.     

Robust Calibration for Localization in Clustered Wireless Sensor Networks

This paper presents a robust calibration procedure for clustered wireless sensor networks. Accurate calibration of between-node distances is one crucial step in localizing sensor nodes in an ad-hoc sensor network. The calibration problem is formulated as a parameter estimation problem using a linear calibration model. For reducing or eliminating the unwanted influence of measurement corruptions or outliers on parameter estimation, which may be caused by sensor or communication failures, a robust regression estimator such as the least-trimmed squares (LTS) estimator is a natural choice. Despite the availability of the FAST-LTS routine in several statistical packages (e.g., R, S-PLUS, SAS), applying it to the sensor network calibration is not a simple task. To use the FAST-LTS, one needs to input a trimming parameter, which is a function of the sensor redundancy in a network. Computing the redundancy degree and subsequently solving the LTS estimation both turn out to be computationally demanding. Our research aims at utilizing some cluster structure in a network configuration in order to do robust estimation more efficiently. We present two algorithms that compute the exact value and a lower bound of the redundancy degree, respectively, and an algorithm that computes the LTS estimation. Two examples are presented to illustrate how the proposed methods help alleviate the computational demands associated with robust estimation and thus facilitate robust calibration in a sensor network.     

An efficient joint channel assignment and QoS routing protocol for IEEE 802.11 multi-radio multi-channel wireless mesh networks

With the emerging of video, voice over IP (VoIP) and other real-time multimedia services, more and more people pay attention to quality of service (QoS) issues in terms of the bandwidth, delay and jitter, etc. As one effective way of broadband wireless access, it has become imperative for wireless mesh networks (WMNs) to provide QoS guarantee. Existing works mostly modify QoS architecture dedicated for ad hoc or sensor networks, and focus on single radio and single channel case. Meanwhile, they study the QoS routing or MAC protocol from view of isolated layer. In this paper, we propose a novel cross-layer QoS-aware routing protocol on OLSR (CLQ-OLSR) to support real-time multimedia communication by efficiently exploiting multi-radio and multi-channel method. By constructing multi-layer virtual logical mapping over physical topology, we implement two sets of routing mechanisms, physical modified OLSR protocol (M-OLSR) and logical routing, to accommodate network traffic. The proposed CLQ-OLSR is based on a distributed bandwidth estimation scheme, implemented at each node for estimating the available bandwidth on each associated channel. By piggybacking the bandwidth information in HELLO and topology control (TC) messages, each node disseminates information of topology and available bandwidth to other nodes in the whole network in an efficient way. From topology and bandwidth information, the optimized path can be identified. Finally, we conduct extensive simulation to verify the performance of CLQ-OLSR in different scenarios on QualNet platform. The results demonstrate that our proposed CLQ-OLSR outperforms single radio OLSR, multi-radio OLSR and OLSR with differentiated services (DiffServ) in terms of network aggregate throughput, end-to-end packet delivery ratio, delay and delay jitter with reasonable message overheads and hardware costs. In particular, the network aggregate throughput for CLQ-OLSR can almost be improved by 300% compared with the single radio case.     

关于无线传感器网络节能问题的研究——基于定向扩散路由协议的改进的探讨

定向扩散路由协议作为无线传感器网络的一种重要的典型网络协议,是高能源有效性协议的代表。然而它有着明显缺点,那便是在初始和更新查询阶段存在着极大的开销。文章直接针对这个问题,以节能为目的,提出引入选择节点转发的方法来改进定向扩散路由协议。最后通过模拟实验得出的结果显示改进后的定向扩散路由协议能节省能量17.8%。改进后的定向扩散路起到了很好的节能效果。