A Survey on Opportunistic Routing Protocols for Wireless Sensor Networks
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paper_title: Routing in Wireless Sensor Networks

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Wireless sensor networks are formed by small sensor nodes communicating over wireless links without using a fixed network infrastructure. Sensor nodes have a limited transmission range, and their processing and storage capabilities as well as their energy resources are also limited. Routing protocols for wireless sensor networks have to ensure reliable multi-hop communication under these conditions. We describe design challenges for routing protocols in sensor networks and illustrate the key techniques to achieve desired characteristics, such as energy efficiency and delivery guarantees. We give a survey of state-of-the-art routing techniques with a focus on geographic routing, a paradigm that enables a reactive message-efficient routing without prior route discovery or knowledge of the network topology. Different geographic routing strategies are described as well as beaconless routing techniques. We also show the physical layer impact on routing and outline further research directions.
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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: Energy-Efficient Opportunistic Routing in Wireless Sensor Networks

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Opportunistic routing, has been shown to improve the network throughput, by allowing nodes that overhear the transmission and closer to the destination to participate in forwarding packets, i.e., in forwarder list. The nodes in forwarder list are prioritized and the lower priority forwarder will discard the packet if the packet has been forwarded by a higher priority forwarder. One challenging problem is to select and prioritize forwarder list such that a certain network performance is optimized. In this paper, we focus on selecting and prioritizing forwarder list to minimize energy consumption by all nodes. We study both cases where the transmission power of each node is fixed or dynamically adjustable. We present an energy-efficient opportunistic routing strategy, denoted as EEOR. Our extensive simulations in TOSSIM show that our protocol EEOR performs better than the well-known ExOR protocol (when adapted in sensor networks) in terms of the energy consumption, the packet loss ratio, and the average delivery delay.
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paper_title: Opportunistic routing for wireless ad hoc and sensor networks: Present and future directions

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Opportunistic routing has recently attracted much attention as it is considered a promising direction for improving the performance of wireless ad hoc and sensor networks. With opportunistic routing, intermediate nodes collaborate on packet forwarding in a localized and consistent manner. Opportunistic routing greatly increases transmission reliability and network throughput by taking advantage of the broadcast nature of the wireless medium. In this article we first illustrate the basic idea behind opportunistic routing, and then categorize current research work based on different criteria. We illustrate how different protocols work, and discuss their merits and drawbacks. Finally, we point out potential issues and future directions in opportunistic routing for wireless ad hoc and sensor networks.
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paper_title: a high-throughput path metric for multi-hop wireless routing

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This paper presents the expected transmission count metric (ETX), which finds high-throughput paths on multi-hop wireless networks. ETX minimizes the expected total number of packet transmissions (including retransmissions) required to successfully deliver a packet to the ultimate destination. The ETX metric incorporates the effects of link loss ratios, asymmetry in the loss ratios between the two directions of each link, and interference among the successive links of a path. In contrast, the minimum hop-count metric chooses arbitrarily among the different paths of the same minimum length, regardless of the often large differences in throughput among those paths, and ignoring the possibility that a longer path might offer higher throughput.This paper describes the design and implementation of ETX as a metric for the DSDV and DSR routing protocols, as well as modifications to DSDV and DSR which allow them to use ETX. Measurements taken from a 29-node 802.11b test-bed demonstrate the poor performance of minimum hop-count, illustrate the causes of that poor performance, and confirm that ETX improves performance. For long paths the throughput improvement is often a factor of two or more, suggesting that ETX will become more useful as networks grow larger and paths become longer.
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Title: A Survey on Opportunistic Routing Protocols for Wireless Sensor Networks

Section 1: Introduction
Description 1: This section introduces wireless sensor networks (WSNs), their applications, the challenges in designing routing protocols, and the concept of Opportunistic Routing (OR) in WSNs.

Section 2: Literature Survey
Description 2: This section provides a brief survey on different opportunistic routing protocols, discussing specific examples and key ideas.

Section 3: Geographic Random Forwarding (GeRaF) for Ad Hoc and Sensor Networks
Description 3: This section discusses the Geographic Random Forwarding scheme and its approach towards multihop performance in ad hoc and sensor networks.

Section 4: ExOR: Opportunistic Multi-Hop Routing for Wireless Networks
Description 4: This section covers ExOR, the first practical implementation of Opportunistic Routing, highlighting its mechanism and drawbacks.

Section 5: Minimum Transmission Scheme (MTS)
Description 5: This section explains the MTS algorithm proposed for selecting forwarding lists to minimize expected transmission rates under ideal ACK conditions.

Section 6: Simple, Practical, and Effective Opportunistic Routing for Short-Haul Multi-Hop Wireless Networks
Description 6: This section describes an effective opportunistic routing scheme for short-haul multi-hop wireless networks, focusing on reducing packet duplication and increasing throughput.

Section 7: Spectrum Aware Opportunistic Routing in Cognitive Radio Networks
Description 7: This section discusses Spectrum Aware Opportunistic Routing (SAOR) for cognitive radio networks, emphasizing metrics for optimal link transmission and Quality of Service (QoS) guarantees.

Section 8: Energy-Efficient Opportunistic Routing in Wireless Sensor Networks
Description 8: This section explains the Energy Efficient Opportunistic Routing (EEOR) protocol, which aims to minimize energy consumption and improve network performance in WSNs.

Section 9: A Trusted Opportunistic Routing Algorithm for VANET
Description 9: This section covers a trusted opportunistic routing algorithm designed for vehicular ad hoc networks (VANETs), focusing on security and trust mechanisms.

Section 10: Social Relation Opportunistic Routing (SROR) for MANETs
Description 10: This section proposes the SROR protocol for Mobile Adhoc Networks (MANETs), considering social relations, mobility patterns, and social profiles for routing decisions.

Section 11: Opportunistic Routing Algorithm for Relay Node Selection in Wireless Sensor Networks
Description 11: This section discusses an algorithm for relay node selection in WSNs, focusing on energy savings and network lifetime improvement.

Section 12: Conclusion and Future Directions
Description 12: This section concludes the survey, summarizing the advantages of opportunistic routing in WSNs, and discusses potential future directions, particularly in energy-saving techniques.