Energy Efficient Routing Protocols In Wireless Sensor Network: A Survey

Najm-us-Sama

Department of Computer Sciences and Information, Al-Jouf University, Jouf, KSA

Abstract- A wireless sensor network is a special kind of ad-hoc network with distributed sensing and processing capability. A wireless sensor network can be used in a wide range of applications such as environmental monitoring, in-plant robotic control, smart homes, military surveillance, industrial applications, forests, habitat monitoring, farmlands and precision agriculture. Due to their potential applications, such networks have particular features imposed by resource restrictions, such as low computational power, reduced bandwidth and especially the limited power source.

Due to some unique characteristics a wireless sensor network differs from other networks. The most important feature is energy efficiency. A sensor node has a finite battery power and it is often unattainable to recharge the node's battery. Routing protocols for wireless sensor networks are responsible for maintaining the routes in the network and have to ensure reliable multi-hop communication. Thus, the routing protocol for a wireless sensor network should be as energy efficient as possible. In this paper, we give a review of energy efficient routing protocols for Wireless Sensor Network and compare their main objectives and strengthens. The routing Protocols are classified on the basis of network architecture and network objectives. Network objectives are further classified into primary and secondary objectives.

Keywords— Wireless Sensor Network, Routing Protocols, Energy Efficiency.

  1. Introduction

A wireless sensor network (WSN) consists of sensing devices with an inbuilt capability to communicate with other nodes through small transceivers. These sensors are distributed in the sensor field to monitor targeted area. The number of sensor nodes in a network may vary and a large sensor network exists with thousands of nodes in it. Usually some of the nodes in wireless sensor network are used as sensors which may act as a source that generates data. This data reaches to the sink either in a mutihop fashion or in a single hop fashion if the source is a neighbor of the sink. Each node in a WSN is equipped with a radio transceiver, a small microprocessor, an energy source or a battery and some other electronics components. The cost of sensor nodes varies with specification of resources such as memory size, computational speed and bandwidth. The WSNs may be used in a variety of everyday life activities or services such as environmental monitoring, in-plant robotic control, smart homes, military surveillance, industrial applications, forests, habitat monitoring, farmlands and precision agriculture.

Routing is the main element for WSNs and the primary design goals and challenges for routing protocols are scalability, reliability, lifetime, QoS and energy efficiency. The ways in which routing protocols work make them suitable for certain applications.

Energy efficiency is very important for routing protocol because routing protocol is responsible for maintaining the routes in the network and have to ensure reliable multi-hop communication. Various energy-efficient routing protocols have been designed and developed for WSNs in order to support efficient data delivery to their destination. Thus, each energy-efficient routing protocol may have specific characteristics depending on the application and network architecture. The main contribution of this paper is to provide an exhaustive survey on the energy-efficient routing protocols for WSNs.

This paper classified the energy efficient routing protocols based on the architecture and objectives of WSNs as shown in figure 1. Then the objectives are further classified into primary and secondary. In this survey, wediscuss all those routing protocols whose primary objectives are energy efficiency with a different secondaryobjective. The proposed survey presents the comparison of different routing protocols for WSNs shown in TAble 1.

In Section II we describe the related work about energy efficient routing protocolservays till 2013. Section III describes energy efficient routing protocol and their comparison. Section IV concludes the paper.

  1. Related Work

There is a large number of current works, as well as efforts that are on the go, for the development of routing protocols in WSNs. These protocols are developed based on the application needs and the architecture of the network. However, there are factors that should be taken into consideration when developing routing protocols for WSNs. The most important factor is the energy efficiency of the sensors that directly affects the extension of the lifetime of the network. There are several surveys in the literature on routing protocols in WSNs and an attempt is made to present below and discuss the existing differences between them and our work.

The authors make an extensive survey on design issues and techniques for WSNs. They depict the proposed protocols for all the layers of the network stack and the physical constraints of sensor nodes. The possible applications of sensor networks are discussed, but the paper does not make a classification for such routing [1]. In [2], the authors presents a survey on routing protocols in WSNs. The proposed survey classifies the routing techniques, based on the network structure, into three categories: flat, hierarchical, and location-based routing protocols. In addition to, these protocols are classified into multipath-based, query-based, negotiation based, and QoS-based routing techniques depending on the protocol operation. This survey exhibits a good number of energy efficient routing protocols that have been developed for WSNs. It describesthe limited energy supply, limited computing power and limited bandwidth of the wireless links connecting sensor nodes and also presents the Routing Challenges and Design Issues of WSNs. Also, the design tradeoffs between energy and communication overhead savings in some of the routing model, as well as the pros and cons of each routing technique are spotlighted.

The authors in [3] classifies the routing protocole into data-centric, hierarchical and location-based. This survey presents routing protocols for WSNs but it does not take energy efficient routing protocols into consideration. In [4], authors dicsusses algorithms which are classified in two classes that take into consideration the energy-aware broadcast/multicast problem. The algorithms are classified in the MEB/MEM (minimum energy broadcast/multicast) problem and the MLB/MLM (maximum lifetime broadcast/multicast) problem in wireless ad hoc networks. Minimizing the total transmission power consumption of all nodes involved in the multicast session and maximizing the operation time until the battery depletion of the first node involved in the multicast session are the two main energy-aware metrics that are considered. The survey in [5], classifies the problems into three different categories: internal platform and underlying operating system, communication protocol stack, network services, provisioning, and deployment. But the paper neither discusses the energy efficient routing protocols developed on WSNs nor provides a detailed comparison of the protocols.

In [6], the authors present a survey in which the protocols are classified into duty-cycling, data-driven and mobility based. Proposed survey provide observations about the different approaches to energy management and highlight that the energy consumption of the radio is much higher than the energy consumption due to data sampling or data processing. But, many real applications have shown the power consumption of the sensor is similar to, or even greater than, the power needed by the radio. The survey deduced that the sampling phase may need a long time, especially compared to the time needed for communications, so that the energy consumption of the sensor itself can be very high as well. This survey focused on the energy consumption based on the hardware components of a typical sensor node. And discussed the architecture and power breakdown as the solution to reduce power consumption in wireless sensor networks. In [7], presents the design issues of WSNs and classification of routing protocols. Also discussed a few routing protocols based on their characteristics and the mechanisms they use in order to extend the network lifetime without providing details on each of the described protocols. But the proposed surveydoes not present a direct comparison of the discussed protocols.

The challenges in the designing of the energy-efficient Medium Access Control (MAC) protocols for the WSNs are presented in [8]. Furthermore, it describes few MAC protocols for the WSNs emphasizing their strengths and weaknesses. However, the proposed survey neither discusses the energy-efficient routing protocols developed on WSNs nor provides a detailed comparison of the protocols. In [9] the authors presents few energy-efficient routing techniques for Wireless Multimedia Sensor Networks (WMSNs) and highlight the performance issues of each strategy. They summarize that the design challenges of routing protocols for WMSNs followed of the weaknesses of current techniques designed for non-multimedia data transmission. Further, they classify recent routing protocols for WMSNs. This proposed survey discusses some issues on energy efficiency in WSNs and it is mostly based on the energy efficient techniques combining QoS Assurance for WMSNs. The authors in [10] classified energy efficient routing protocols into four main schemes: Network Structure, Communication Model, Topology Based and Reliable Routing. The proposed paper provide an analytical survey on energy efficient routing protocols for WSNs. As compared to other routing protocoles the hierarchical routing protocol is more energy-efficient. In [11] the authors discussed Secure Energy-Efficient Hierarchical Routing Protocols in WSNs and compare them in terms of security, performance and efficiency. The paper also discussed Security issues for WSNs and their solutions.

Although, there is a good number of surveys in wirelss sensor network but this servay provides energy efficient routing protocols in WSNs and presents the comparison between them. The proposed work will help the readers to pick the most suitable energy efficient routing protocol for their network.

  1. Energy Efficient Routing Protocole's

Wireless sensor network is a great favor to wireless technology which can be used in various critical applications, making it more well-known in emerging technologies which we use in our day to day life. Even though it has several advantages, it has some disadvantages like limited communication bandwidth, energy consumption etc. Many energy effcient routing protocoles are developed to minimize energy consumption since energy resource is the major life factor for a node. We presents some of energy efficient routing protocols which will help the readers to choose the most appropriate energy efficient routing protocol for their network.

The author in [12] proposed an enhancement of LEACH-C protocol, instead of using constant round time usage of adaptive variable round time method provides a multi-hop communication between distance nodes to base station. To evenly distributes the energy load among the sensor nodes and use the multi hop approach for the CHs an EEICCP (Energy efficient inter cluster coordination) protocol has been proposed. EEICCP has shown exceptional improvement over already existing LEACH and HCR protocols in terms of reliability and stability [13]. For energy conservation the authors proposed Equalized Cluster Head Election Routing Protocol (ECHERP). In order to extend the network lifetime ECHERP calculates the combinations of nodes that can be chosen as cluster heads by using the Gaussian elimination algorithm. This protocol improves network energy efficiency as compared against other well-known protocols[14]. The authors proposed a heuristic neighbor selection mechanism in WSNs that uses the geographic routing mechanism combined with the QoS requirements to provide multiobjectiveQoS routing (MQoSR) protocole for different application requirements. The QoS routing problem is formulated as link, and path-based metrics. The link-based metrics are devided in terms of reliability, distance to sink, energy and delay, and the path-based metrics are partitioned in terms of end-to-end delay, network lifetime and reliability of data transmission. MQoSR protocol outperforms the other routing protocols in terms of reliable data transmission, time data delivery, and routing overhead[15].

For a reactive homogeneous WSNs the author's proposed a HEER (Hybrid Energy Efficient Reactive) protocol. In HEER, the selection of cluster Head(CH) is based on the ratio of remaining energy of node and average energy of network. Results show that prposedprotocole prolonged the network lifetime and significantly increased stability period[16]. Multipath Energy-Efficient data Routing Protocol for wireless sensor networks (EERP) is proposed in [17]. In EERP, a node bases its routing decision on two metrics: state and cost function. For all its neighbours concerned with minimum cost function each node searches its Neighbours Information Table. EERP protocol balances the energy consumption and achieves an apparent improvement on the network lifetime.For an optimal number of cluster head selection the authors divide a large sensor field into rectangular clusters in [18]. For efficient communication between cluster heads and a base station the rectangular clusters are further grouped into zones. The proposed routing protocol outperforms in large areas in comparison with the LEACH, MH-LEACH, and SEP routing protocols. The authors proposed an energy efficient routing protocol, named (energy-efficient depth-based routing protocol) EEDBR for UWSNs. Simulation shows that EEDBR contributes to the performance improvements in terms of the network lifetime, energy consumption, and end-to-end delay [19].

For three level heterogeneous wireless sensor network the authors proposed a Centralized Energy Efficient Clustering (CEEC) routing protocol. In the proposed CEEC, whole network area is divided into three equal regions, in which nodes with same power are placed in same region [20]. To utilize physical distance as a routing metric and to balance energy consumption among sensors the authors proposed in R-ERP2R (Reliable Energy-efficient Routing Protocol [21]. To provide reliability and the residual energy of the forwarding nodes to extend network lifetime, during the selection of forwarding nodes the link quality towards the forwarding nodes is also considered. The results show that R-ERP2R performs better in UWSNs.

To extend the network lifetime the author in [22] proposed a cluster based dynamic and energy efficient routing scheme with optimal transmission range (DEOR) for wireless sensor networks. In DEOR, nodes are classified in different ranks depending on the nature of their power consumption in terms of both direct communication to the Base Station and optimal transmission range. From simulation a better outcome has been observed. For energy efficiency the authors EEHCRP (Energy-Efficient Hierarchical Clustering Routing Protocol), a protocol for wireless sensor networks. The network is devided into annular rings by using various power levels at base station. From the results it is observed that the performance of EEHCRP is better in terms of energy consumption of CH, number of clusters and lifetime of network compared with LEACH[23].

Figure 1:Classsification of Energy Efficient routing protocols in WSNs

Table 1. Comparison Table of Energy Efficient Routing Protocols in WSNs

Year / Authors / Homogenous/ Hetrogenous / Title / Literature / Strengthens / Objective / Architecture
2013 / N. Thangadurai
and
R.Dhanasekaran / Hetrogenous / VR-LEACH / [12] /
  1. This protocol can be used for larger geographical region with less energy consumption and less cluster head death.
  2. By using NS2 simulator the results show the improvement of overall network efficiency by comparing with existing protocols.
/
  1. Enhancement of LEACH-C protocol.
  2. Minimize energy consumption.
  3. Design energy efficient routing protocole.
/ Hierarchical Based Routing
2013 / ShalliRani,
JyoteeshMalhotra
And
Rajneesh Talwar / Hetrogenous / EEICCP / [13] /
  1. Evenly distributes the energy load among the sensor nodes
  2. EEICCP use the multi hop approach for the CHs which is an optimal solution as copmared to direct transmission.
  3. In terms of reliability and stability EEICCP has shown remarkable improvement over already existing LEACH and HCR protocols .
/
  1. Design an energy efficient inter cluster coordination protocol
  2. To achive longevity and scalability of the network.
/ Hierarchical Based Routing
2013 / Stefanos A. Nikolidakis, DionisisKandris, Dimitrios D. Vergados and Christos Douligeris / Hetrogenous / ECHERP / [14] / Performance analysis shows the effectiveness of ECHERP in terms of energy coservation and network lifetime. /
  1. Energy conservation through balanced clustering.
  2. To extend the network lifetime.
/ Hierarchical Based Routing
2013 / Hind Alwan
And
AnjaliAgarwal / Homogenous / MQoSR / [15] /
  1. Due to optimum path selection process, the achieved data delivery ratio is always above the required one.
  2. MQoSR protocol is able to achieve the delay requirements and relibale data transmission.
  3. Enhanced network lifetime through efficient utalization of energy.
/
  1. To design Quality-of-service (QoS) aware routing protocol in wireless networks.
  2. Relibality and Data Delivery
  3. Maximum Lifetime
  4. Energy efficient routing
/ Location Based Routing
2013 / N. Javaid,
S. N. Mohammad, K. Latif, U. Qasim,
Z. A. Khan,
And M. A. Khan / Homogenous / HEER / [16] /
  1. Prolonged the network lifetime
  2. Significantly increased stability period.
/
  1. To develop a protocol for a reactive homogeneous WSNs.
  2. Energy conservation
/ Hierarchical Based Routing
2013 / SamraBoulfekhar
And
Mohammed Benmohammed / Homogenous / EERP / [17] /
  1. EERP proposed distributed multipath search algorithm to discover multiple paths between the sink and source nodes.
  2. It minimizes and balances the energy consumption well among all sensor nodes.
  3. EERP protocole achieves an improvement on the network lifetime.
/
  1. To maximize netowrk lifetime and connectivity.
  2. Designing of Multipath routing protocole instead of single path routing protocole.
/ Flate Based Routing
2012 / Shalli Rani1, JyoteeshMalhotra, And
Rajneesh Talwar / Hetrogenous / AZR-LEACH / [18] /
  1. AZR-LEACH routing protocol works efficiently in large as well as small areas.
  2. Optimal number of cluster head selection.
  3. Efficient communication between cluster heads and a base station.
  4. It outperforms in large areas in comparison with the LEACH, MH-LEACH, and SEP routing protocols.
/
  1. To design energy efficient routing Potocole
  2. Efficient cluster heads selection
  3. Network stability and Throughput
  4. Minimize Energy consumption
  5. Network lifetime
/ Hierarchical Based Routing
2012 / AbdulWahid
and
Dongkyun Kim / Homogenous / EEDBR / [19] /
  1. In EEDBR the remaining energy of sensor nodes is taken into account in order to improve the network lifetime.
  2. Using NS2 simulation, it observed that EEDBR contributes to the performance improvements in terms of the network lifetime, energy consumption, and end-to-end delay.
/
  1. To design network/routing protocols for Underwater Wireless Sensor Networks UWSNs.
  2. Achieve enenrgy efficiency in unpleasant underwater environment.
/ Flate Based Routing
2012 / M. Aslam, T. Shah, N. Javaid, A. Rahim, Z. Rahman
And
Z. A. Khan / Hetrogenous / CEEC / [20] /
  1. CEEC has maximum throughput and network lifetime.
  2. Is very efficient in successful data delivery.
  3. CEEC is about 40%, 70%, 70%, 100% better in stability as compare to DEEC, SEP, E-SEP and LECAH respectively.
  4. CEEC provides optimal number of CHs for every round.
/
  1. To design energy efficeint routing protocole for heterogeneous wireless sensor network.
  2. To find out optimal number of CHs.
/ Hierarchical Based Routing
2012 / Abdul Wahid, Sungwon Lee
and
Dongkyun Kim / Homogenous / R-ERP2R / [21] /
  1. R-ERP2R is compared against a well-known routing protocol (i.e. depth-based routing) in terms of network lifetime, energy consumption, end-to-end delay and delivery ratio using the NS-2 simulator.
  2. It improves the end-to-end delay from 35% to 67% in random topologies and 38% to 71% in grid topologies against ERP2R.
  3. The delivery ratio of R-ERP2R is 12% to 22% more than ERP2R in random topologies and 7% to 19% in grid topologies
/
  1. To design a routing protocol for successful data transmissions between sensors and the sink in underwater wireless sensor networks (UWSNs)
  2. Reliability
  3. Energy efficiency
  4. Maximum lifetime
/ Flate Based Routing
2012 / MdGolamMurshed,
and
Alastair R. Allen / Heterogeneous / DEOR / [22] / Energy Efficient Dynamic Routing Protocol have better outcome as compared to one of the multihop routing strategies. /
  1. To minimize the oveall energy consumption.
  2. To enhance the network lifespane.
  3. Designing a pawer-aware routing protocole.
/ Hierarchical Based Routing
2012 / Diwakar
Meenakshi,
And
Sushil Kumar / Hetrogenous / EEHCRP / [23] / The results are obtained in terms of three metrics, lifetime of the network, and number of clusters and energy consumption of clusters heads. From the results of simulation, it is observed that the performance of EEHCRP is better in terms of energy consumption of CH, number of clusters and lifetime of network compared with LEACH. / To develope a routing protocole which efficiently utilized sensor nodes energy to maintain a prolonged network lifetime. / Hierarchical Based Routing
  1. Conclusions

Routing protocols for wireless sensor networks are responsible for maintaining the routes in the network and have to ensure reliable multi-hop communication. Thus, the routing protocol for a wireless sensor network should be as energy efficient as possible. In this paper we provides an analytical survey emphasizing on the energy-efficient routing protocols in WSNs and compare their main objectives and strengthens. The proposed survey focused on the energyefficient routing protocols in WSNs that can provide directions to the readers on how to choose the most suitable energy efficient routing protocol for their network.