A Survey of QoS Based Routing Protocols for Wireless Sensor Networks
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paper_title: Habitat monitoring: application driver for wireless communications technology

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As new fabrication and integration technologies reduce the cost and size of micro-sensors and wireless interfaces, it becomes feasible to deploy densely distributed wireless networks of sensors and actuators. These systems promise to revolutionize biological, earth, and environmental monitoring applications, providing data at granularities unrealizable by other means. In addition to the challenges of miniaturization, new system architectures and new network algorithms must be developed to transform the vast quantity of raw sensor data into a manageable stream of high-level data. To address this, we propose a tiered system architecture in which data collected at numerous, inexpensive sensor nodes is filtered by local processing on its way through to larger, more capable and more expensive nodes.We briefly describe Habitat monitoring as our motivating application and introduce initial system building blocks designed to support this application. The remainder of the paper presents details of our experimental platform.
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paper_title: Routing Techniques in Wireless Sensor Networks: A Survey

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Wireless sensor networks consist of small nodes with sensing, computation, and wireless communications capabilities. Many routing, power management, and data dissemination protocols have been specifically designed for WSNs where energy awareness is an essential design issue. Routing protocols in WSNs might differ depending on the application and network architecture. In this article we present a survey of state-of-the-art routing techniques in WSNs. We first outline the design challenges for routing protocols in WSNs followed by a comprehensive survey of routing techniques. Overall, the routing techniques are classified into three categories based on the underlying network structure: flit, hierarchical, and location-based routing. Furthermore, these protocols can be classified into multipath-based, query-based, negotiation-based, QoS-based, and coherent-based depending on the protocol operation. We study the design trade-offs between energy and communication overhead savings in every routing paradigm. We also highlight the advantages and performance issues of each routing technique. The article concludes with possible future research areas.
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paper_title: Energy aware routing for low energy ad hoc sensor networks

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The recent interest in sensor networks has led to a number of routing schemes that use the limited resources available at sensor nodes more efficiently. These schemes typically try to find the minimum energy path to optimize energy usage at a node. In this paper we take the view that always using lowest energy paths may not be optimal from the point of view of network lifetime and long-term connectivity. To optimize these measures, we propose a new scheme called energy aware routing that uses sub-optimal paths occasionally to provide substantial gains. Simulation results are also presented that show increase in network lifetimes of up to 40% over comparable schemes like directed diffusion routing. Nodes also burn energy in a more equitable way across the network ensuring a more graceful degradation of service with time.
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paper_title: Highly-resilient, energy-efficient multipath routing in wireless sensor networks

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Previously proposed sensor network data dissemination schemes require periodic low-rate flooding of data in order to allow recovery from failure. We consider constructing two kinds of multipaths to enable energy efficient recovery from failure of the shortest path between source and sink. Disjoint multipath has been studied in the literature. We propose a novel braided multipath scheme, which results in several partially disjoint multipath schemes. We find that braided multipaths are a viable alternative for energy-efficient recovery from isolated and patterned failures.
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paper_title: Service Differentiation in Sensor Networks

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Abstract Recent technological advances have made it possible to havelarge wireless ad-hoc networks of small devices. The primepurpose of such sensor networks is to disseminate informationabout the environmentthey sense. We observethat informationprovidedmayhavedifferent levelsof importanceandarguethatthe sensor networks should be willing to spend more resourcesin disseminating packets carrying more important information.In this paper, weintroducethe conceptof servicedifferenti-ationasapplicabletosensornetworks,highlightitsfundamentaldifferences with normal data networks and deﬁne the relevantmetrics. Variousmechanismswhichmay provideservicescom-patible with the packet priority levels are proposed. We evalu-ate one of the proposedmethod , Adaptive Forwarding Scheme(AFS) and show that our scheme provides the desired levels ofservice. Keywords SensorNetworks,ServiceDifferentiation, AdaptiveForwardingScheme 1. Introduction Technologicaladvanceshavemade it feasible to havesmall de-vices with computation, communication and sensing capabili-ties [1, 2, 3]. These devices run on batteries and thus their ca-pabilities are limited by the available energy. A sensornetworkconsistingofalargenumberofsuchnodescanbeusefulinkeep-ing track of various activities in a givenregion. However, oper-ations performed in such a sensor network have to be energy-efﬁcient becauseof the energy constraints of its nodes.In a sensor network, sensors would sensesome data, pack-etize it and send the packet to a monitor node along a path con-sisting of multiple wireless hops. Researchers have come upwith schemes to provide the functionality required to performthese operations efﬁciently. For routing the data to the moni-tor node, schemeslike Directed Diffusion [4] and Power-awarerouting [5] have been proposed. Clustering schemes [6, 7, 8]group the nodesinto clusters for network management[7]. Lo-cation dissemination schemes [9, 10] provide the sensors withinformation about their locations. Simple and efﬁcient operat-ing system like tinyOS [3] have been designed for these smallnodes. All these works focus on cutting down on the energyrequirements of a sensor network, while providing the minimalfunctionality for the network to operate.We observe that in sensor networks different data packetsmight have different importance.For example, if a temperaturesensorinaforest,senses60Fonanormalspringday,thevalueis
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paper_title: A survey on routing protocols for wireless sensor networks

paper_content:

Recent advances in wireless sensor networks have led to many new protocols specifically designed for sensor networks where energy awareness is an essential consideration. Most of the attention, however, has been given to the routing protocols since they might differ depending on the application and network architecture. This paper surveys recent routing protocols for sensor networks and presents a classification for the various approaches pursued. The three main categories explored in this paper are data-centric, hierarchical and location-based. Each routing protocol is described and discussed under the appropriate category. Moreover, protocols using contemporary methodologies such as network flow and quality of service modeling are also discussed. The paper concludes with open research issues. � 2003 Elsevier B.V. All rights reserved.
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paper_title: QoS Support in Wireless Sensor Networks : A Survey

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In this paper, we assess the state of the art of Quality of Services (QoS) support in wireless sensor networks (WSNs). Unlike traditional end-to-end multimedia applications, many non-end-to-end mission-critical applications envisioned for WSNs have brought forward new QoS requirements on the network. Further, unique characteristics of WSNs, such as extremely resource-constrained sensors, large-scale random deployment, and novel data-centric communication protocols, pose unprecedented challenges in the area of QoS support in WSNs. Thus, we first review the techniques for QoS support in traditional networks, analyze new QoS requirements in WSNs from a wide variety of applications classified by data delivery models, and propose some non-end-to-end collective QoS parameters. Next, the challenges of QoS support in this new paradigm are presented. Finally, we comment on current research efforts and identify many exciting open issues in order to stimulate more research interest in this largely unexplored area. Keywords— Wireless networks, wireless sensor networks, QoS, collective QoS
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paper_title: An efficient N-to-1 multipath routing protocol in wireless sensor networks

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A typical task in a wireless sensor network is that every sensor node senses its local environment and, upon request, sends the data of interest back to a base station. Based on this many-to-one communication pattern, we first propose a distributed N-to-1 multipath discovery protocol which distinguishes from other multipath routing protocols in that it is able to find multiple node-disjoint paths from every sensor node to the base station simultaneously in one route discovery process. Then we propose a hybrid multipath data collection scheme which combines end-to-end multipath traffic dispersion and per-hop alternate path salvaging. Our simulation results show that the proposed N-to-1 multipath discovery protocol is highly efficient and the hybrid data collection scheme based on it provides a seamlessly more reliable and more secure data collection service in wireless sensor networks
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paper_title: Energy aware routing for low energy ad hoc sensor networks

paper_content:

The recent interest in sensor networks has led to a number of routing schemes that use the limited resources available at sensor nodes more efficiently. These schemes typically try to find the minimum energy path to optimize energy usage at a node. In this paper we take the view that always using lowest energy paths may not be optimal from the point of view of network lifetime and long-term connectivity. To optimize these measures, we propose a new scheme called energy aware routing that uses sub-optimal paths occasionally to provide substantial gains. Simulation results are also presented that show increase in network lifetimes of up to 40% over comparable schemes like directed diffusion routing. Nodes also burn energy in a more equitable way across the network ensuring a more graceful degradation of service with time.
---
paper_title: Highly-resilient, energy-efficient multipath routing in wireless sensor networks

paper_content:

Previously proposed sensor network data dissemination schemes require periodic low-rate flooding of data in order to allow recovery from failure. We consider constructing two kinds of multipaths to enable energy efficient recovery from failure of the shortest path between source and sink. Disjoint multipath has been studied in the literature. We propose a novel braided multipath scheme, which results in several partially disjoint multipath schemes. We find that braided multipaths are a viable alternative for energy-efficient recovery from isolated and patterned failures.
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paper_title: Protocols for self-organization of a wireless sensor network

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We present a suite of algorithms for self-organization of wireless sensor networks in which there is a scalably large number of mainly static nodes with highly constrained energy resources. The protocols further support slow mobility by a subset of the nodes, energy-efficient routing, and formation of ad hoc subnetworks for carrying out cooperative signal processing functions among a set of the nodes.
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paper_title: Energy-aware routing in cluster-based sensor networks

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There has been a growing interest in the applications of sensor networks. Since sensors are generally constrained in on-board energy supply, efficient management of the network is crucial in extending the life of the sensor. We present a novel approach for energy-aware and context-aware routing of sensor data. The approach calls for network clustering and assigns a less-energy-constrained gateway node that acts as a centralized network manager. Based on energy usage at every sensor node and changes in the mission and the environment, the gateway sets routes for sensor data, monitors latency throughout the cluster, and arbitrates medium access among sensors. Simulation results demonstrate that our approach can achieve substantial energy saving.
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paper_title: An energy-aware QoS routing protocol for wireless sensor networks

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Recent advances in wireless sensor networks have led to many new routing protocols specifically designed for sensor networks. Almost all of these routing protocols considered energy efficiency as the ultimate objective in order to maximize the whole network lifetime. However, the introduction of video and imaging sensors has posed additional challenges. Transmission of video and imaging data requires both energy and QoS aware routing in order to ensure efficient usage of the sensors and effective access to the gathered measurements. In this paper, we propose an energy-aware QoS routing protocol, which can also run efficiently with best-effort traffic. The protocol finds a least-cost, delay-constrained path for real-time data in terms of link cost that captures nodes' energy reserve, transmission energy, error rate and other communication parameters. Moreover, throughput for non-real-time data is maximized by adjusting the service rate for both real-time and non-realtime data at sensor nodes. Simulation results have demonstrated the effectiveness of our approach.
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paper_title: SPEED: a stateless protocol for real-time communication in sensor networks

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In this paper, we present a real-time communication protocol for sensor networks, called SPEED. The protocol provides three types of real-time communication services, namely, real-time unicast, real-time area-multicast and real-time area-anycast. SPEED is specifically tailored to be a stateless, localized algorithm with minimal control overhead End-to-end soft real-time communication is achieved by maintaining a desired delivery speed across the sensor network through a novel combination of feedback control and non-deterministic geographic forwarding. SPEED is a highly efficient and scalable protocol for sensor networks where the resources of each node are scarce. Theoretical analysis, simulation experiments and a real implementation on Berkeley motes are provided to validate our claims.
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paper_title: MMSPEED: multipath Multi-SPEED protocol for QoS guarantee of reliability and. Timeliness in wireless sensor networks

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In this paper, we present a novel packet delivery mechanism called Multi-Path and Multi-SPEED Routing Protocol (MMSPEED) for probabilistic QoS guarantee in wireless sensor networks. The QoS provisioning is performed in two quality domains, namely, timeliness and reliability. Multiple QoS levels are provided in the timeliness domain by guaranteeing multiple packet delivery speed options. In the reliability domain, various reliability requirements are supported by probabilistic multipath forwarding. These mechanisms for QoS provisioning are realized in a localized way without global network information by employing localized geographic packet forwarding augmented with dynamic compensation, which compensates for local decision inaccuracies as a packet travels towards its destination. This way, MMSPEED can guarantee end-to-end requirements in a localized way, which is desirable for scalability and adaptability to large scale dynamic sensor networks. Simulation results show that MMSPEED provides QoS differentiation in both reliability and timeliness domains and, as a result, significantly improves the effective capacity of a sensor network in terms of number of flows that meet both reliability and timeliness requirements up to 50 percent (12 flows versus 18 flows).
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paper_title: Multiconstrained QoS multipath routing in wireless sensor networks

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Sensor nodes are densely deployed to accomplish various applications because of the inexpensive cost and small size. Depending on different applications, the traffic in the wireless sensor networks may be mixed with time-sensitive packets and reliability-demanding packets. Therefore, QoS routing is an important issue in wireless sensor networks. Our goal is to provide soft-QoS to different packets as path information is not readily available in wireless networks. In this paper, we utilize the multiple paths between the source and sink pairs for QoS provisioning. Unlike E2E QoS schemes, soft-QoS mapped into links on a path is provided based on local link state information. By the estimation and approximation of path quality, traditional NP-complete QoS problem can be transformed to a modest problem. The idea is to formulate the optimization problem as a probabilistic programming, then based on some approximation technique, we convert it into a deterministic linear programming, which is much easier and convenient to solve. More importantly, the resulting solution is also one to the original probabilistic programming. Simulation results demonstrate the effectiveness of our approach.
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paper_title: Message-initiated constraint-based routing for wireless ad-hoc sensor networks

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Most existing routing mechanisms differ in routing objectives and routing strategies; however, all the existing routing protocols have in common that the routing objective and destination specification are fixed, and that the routing objective is incorporated only implicitly. We propose a general message specification mechanism to encode explicitly the routing destinations, constraints and objectives in messages, so that general-purpose instead of objective or destination specific routing strategies can be applied. Using general-purpose routing strategies while specifying quality-of-service (QoS) properties explicitly at the application layer in messages, QoS-aware strategies for individual messages are obtained. We also propose two frameworks of general-purpose routing strategies for this type of message specification.
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paper_title: Energy Constrained Multipath Routing in Wireless Sensor Networks

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This paper addresses the issue of Quality of Service (QoS) Routing to improve energy consumption in wireless sensor networks (WSNs). Building upon a previously proposed QoS provisioning benchmark model, we formulate the problem of routing sensed information in a WSN network as a path-based energy minimization problem subject to QoS routing constraints expressed in terms of reliability, delay and geo-spatial energy consumption. Using probabilistic approximations, we transform the path-based model into a link-based model and apply methods borrowed from the zero-one optimization framework to solve this problem. By comparing the performance achieved by its solution to the benchmark model, simulation results reveal that our model outperforms the benchmark model in terms of energy consumption and quality of paths used to route the sensed information.
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paper_title: Energy efficient and QoS based routing protocol for wireless sensor networks

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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. By means of simulations, we evaluate and compare the performance of our routing protocol with the MCMP (Multi-Constraint Multi-Path) routing protocol. Simulation results have shown that our protocol achieves lower average delay, more energy savings, and higher packet delivery ratio than the MCMP protocol.
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paper_title: QuESt: a QoS-based energy efficient sensor routing protocol

paper_content:

Rapid penetration of smart wireless devices and enormous growth of wireless communication technologies has already set the stage for deployment of wireless sensor networks (WSNs). While these small sensor nodes are often considered as the future of wireless communications, they also suffer from energy constraints. On the other hand, with increasing demand for real-time services in next generation wireless networks, quality-of-service (QoS)-based routing has emerged as an interesting research topic. Naturally offering some QoS-guarantee in sensor networks raises significant challenges. The network needs to cope up with battery-constraints, while providing precise QoS (end-to-end delay and bandwidth requirement) guarantee. More precisely, designing such QoS-protocols, optimizing multiple objectives, is computationally intractable. Based on the multi-objective genetic algorithm (MOGA), in this paper we propose a QoS-based energy-efficient sensor routing (QuESt) protocol that determines application-specific, near-optimal sensory-routes demand, by optimizing multiple QoS parameters, (end-to-end delay and bandwidth requirements) and energy consumption. Simulation results demonstrate that the proposed protocol is capable of discovering a set of QoS-based, near-optimal routes, even with imprecise network information. Copyright © 2007 John Wiley & Sons, Ltd.
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Title: A Survey of QoS Based Routing Protocols for Wireless Sensor Networks
Section 1: INTRODUCTION
Description 1: This section introduces the technological advances in wireless sensor networks and outlines the motivations and applications for such networks.

Section 2: THE TAXONOMY OF ROUTING PROTOCOLS
Description 2: This section categorizes and describes the various types of routing protocols specifically designed for wireless sensor networks.

Section 3: QOS ROUTING CHALLENGES
Description 3: This section discusses the various challenges encountered when designing a QoS (Quality of Service) routing protocol for wireless sensor networks.

Section 4: QOS ROUTING PROTOCOLS
Description 4: This section summarizes the existing research on QoS routing protocols, highlighting various proposals and their respective approaches.

Section 5: PERFORMANCE EVALUATION
Description 5: This section presents the simulations performed to evaluate and compare the performance of several QoS routing protocols, describing the simulation setup, performance metrics, and the results.

Section 6: CONCLUSION
Description 6: This section provides a summary of the survey, discussing the main findings, comparisons, and insights on the QoS routing protocols for wireless sensor networks.