A survey on positioning based energy efficient wireless sensor network

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1 A survey on positioning based energy efficient wireless sensor network (Received 17 September, 2016 Accepted 02 October, 2016) Robin Chadha M.TECH scholar, DAVIET Jalandhar, India ABSTRACT Wireless Sensor Network (WSN) is an automated environment of thousands of wireless sensors whose parallel working leads to the accomplishment of specific application. In WSN, each node have the capability of sensing, processing and propagating the sensed data to other nodes. The energy consumed in propagating the sensed information across the whole network directly depends on the positioning of sensor nodes. Positioning of nodes is a research area which gathers lot of attention from the researchers. Multiple algorithms and techniques were developed earlier to determine the individual and relative positions of wireless sensors in the WSN. Moreover efficiency of routing protocols also increases by proper positioning of nodes. In this paper, a review on various position based techniques and routing protocols is presented which are used for sensing the location of sensor nodes in 2D & 3D WSN and discuss some open research issues in WSN for future. Keywords WSN, 2D, 3D, Power consumption 1. INTRODUCTION Wireless sensor networks shown in fig 1 consist of self-governing sensors which are used to monitor physical conditions of an environment. Due to advancement in technology, small size and low cost sensors Love kumar Assistant Professor, DAVIET Jalandhar, India er.lovekumar@gmail.com are designed and deployed in very large numbers to gather the informations specially in applications where presence of humans is not possible. Like in, battlefield surveillance, mines and forests where survival of human being is too difficult. Positioning of nodes plays a crucial role in the overall performance of a WSN. Processing of positioning information is classified into multiple techniques such as centralized positioning technique, distributed positioning technique, cluster based positioning technique etc. Fig 1 WIRELESS SENSOR NETWORK In distributed positioning technique[1], the information sensed by sensors is processed by the sensor itself whereas in centralized positioning technique, sink node is the processing element and all other nodes send 7

2 their information to the sink node. Moreover a hybrid technique called clustering has higher efficiency in terms of energy efficiency in comparison to centralized and distributed positioning techniques. Centralized techniques[1,2] approximates the position of each wireless sensor with respect to a server or a Base Station (BS) in WSN, while in distributed positioning technique, node communicate with each other to get their position in the network and processes information in a collaborative, distributed way. In clustering technique, wireless sensor network is partitioned into multiple clusters and Each cluster is having separate sink node which has the capability of sensing and processing the gathered information in a cluster. In addition to above mentioned techniques, the influence of 2D and 3D positioning methods of sensor nodes can also effect the performance of WSN. are disturbed in 3D WSNs as nodes are placed at different heights with respect to ground levels in it as shown in fig 3. Variation in height of sensors in the network is an important aspect which differentiates 2D from 3D WSN. Fig 3 3D-WSN Underwater sensor networks[3,4] is an example of 3-dimensional WSN as nodes are positioned at different heights from the ocean s ground level. Climate monitoring and better weather forecasting can be performed by setting up a 3-dimensional network in the atmosphere. Certain network parameters like traffic congestion, data routing, coverage, network topology, clustering, etc. can be efficiently improved with proper positioning of wireless sensor nodes. 1.1 WSN performance parameters Fig 2 2D-WSN In 2D WSN networks, all nodes are placed at zero height or at equal height with respect to ground level so that communication between them should be 2 dimensional as shown in fig 2. However, these assumptions There are various performance based parameters which are taken into consideration while setting up a WSN. Some of these parameters are: Operational environmental Condition 8

3 Techniques should be designed by taking into consideration that where they are applicable, which means whether these can be work for interior, exterior, underwater and underground networks. Techniques in which GPS equipped nodes are used may not work in interior, underground and underwater locations as they will require line of sight contact with GPS satellites to find their location. Severe environmental and climatic conditions might also disturb the accuracy of localization techniques used. Many of the algorithms cannot work efficiently in directional networks, as there are numerous obstructions for nodes present in the network Average energy consumption The localization techniques designed for the WSN must possess high efficiency of energy usage for extending node lifetime and better performance levels[5]. This is because when the energy level of a wireless sensor reaches below a certain threshold limit, it will not be able to perform its operations properly, which leads to degradation of the network performance Data Acquirement The amount of energy consumed throughout the acquisition of sensor data depend on the type of monitoring being performed and type of application for which monitoring is performed. The applications which contains mobile nodes, consumes more Energy as compared to nodes which are static[11]. This is because location of mobile nodes changes frequently due to their mobility so they will have to update their location time to time, while static nodes search their positional coordinates only during network formation Processing The energy consumption in processing of information is higher, if we use distributed data processing techniques than centralized data processing technique in a wireless sensor network[2]. The reason behind this is every sensor in the distributed network consist of processing proficiencies that include location estimation & data processing where as these proficiencies are only available with Base Station or Clusterhead in centralized network and all the remaining nodes simply sends their data to the base station or cluster head for processing Data Communication Most of the researchers concluded in their work that communication between nodes of WSN consumes quite large energy as compared to data sensing and processing. The transmission distance between source and sink node and selection of route on the basis of hop count also varies the energy consumption value of sensor nodes for internode as well as internetwork communication; hence the total energy consumption varies with properly placed sensor nodes and by proper selection of route between them. Otherwise, short distance communication between sensor nodes will be more desirable than long distance communication Data integration and reliability Data integration and reliability is the foremost issue which has fascinated a lot researchers in the field of WSN[11]. Employment of network parameter such as like traffic congestion, data routing, coverage, network topology, clustering, etc. 9

4 should not violate the accessibility, reliability and trustworthiness of data in WSN. Sensor network must introduce effective security and error control protocols to save the network data from illegal access or malicious attacks. This will ensures the reliable delivery of data over noisy and error prone environment. networks as each node is communicating directly with the sink node. 2. CLASSIFICATION OF POSITIONING TECHNIQUES Multiple localization schemes has been introduced by the WSN research community to specify the necessity for location information which enhances significance of sensed data in WSN[6]. Mostly, these techniques are categorized on the basis of positioning and processing capabilities of WSN. These capabilities are limited to single node which can be a server in case of centralized network or cluster heads in a clustered networks. In distributed networks, every node has processing and positioning capabilities. Moreover, these schemes are also classified on the basis of the estimation of location of unknown sensor nodes (fixed or dynamic) with respect to already localized nodes, usually called Anchor node. These techniques are considered as Anchor-dependent or Anchor free techniques. 2.1 Centralized positioning In this technique, the whole computation of network data and positioning of nodes is dependent on a single node called central sensor node or sink or base station. This sink node is provided with large amount of energy for positioning, communication and computation. The role of other nodes is just to transfer their data to the sink node for processing. Centralized localization techniques[9,10] works efficiently in small Fig 4 Centralized WSN The accuracy of centralized technique in smaller WSN networks is higher as compared to large WSN networks, because of the high computational energy available to the Base Station and accessibility of global information in the network. The network based on centralized technique uses star topology for positioning purpose. The Base Station (BS) computes the position of each node once during network setup in case of static network. But it has to compute locations of nodes more frequently in case of mobile nodes network which results in high consumption of energy in this case. Due to dependence on single node, the whole network downs if the sink node fails which decreases reliability of this technique. With increase in number of hops/nodes, there is an increase in number of errors and delays. This is because sensor nodes has to depend on more number of nodes to transfer their data to the Base Station (BS). Some of centralized positioning techniques are simulated annealing, least square approximation method, MDS-MAP etc. 2.2 Distributed positioning In Distributed localization technique, 10

5 whole computational load is equally distributed between all the sensor node. This means that instead of sending data to a central location which performs all the computing, the nodes themself process information in a collaborative, distributed way[7][10]. Every sensor node is deployed to estimate its location individually. These techniques are based on highly flexible algorithms and has high computational efficiency for large scale networks[8]. the capability of processing the information sensed by other sensors of that cluster. Fig 6 Clustered WSN Fig 5 Distributed WSN This algorithm generally employs inter node communication for estimating the position of the sensor nodes. Mesh topology is used in distributed localization technique in which each node has a link with every other nodes directly without using any centralized unit. If any node fails, is affects the working of network minimally. In large networks, It is usually hard to implement distributed algorithm. Some of distributed positioning techniques are relaxation based techniques, beacon based techniques, error propagation aware positioning technique. 2.3 Clustering based positioning In clustering based localization [8], the whole wireless sensor network is divided into multiple clusters and and each cluster is having with separate sink node which have The communication between different clusters is basically performed by cluster heads. The cluster head is basically sink node of that particular cluster which have the capacity to process the information sensed by different sensors of that clusters. Clustering provides a way to reduce quick energy reduction from sensor network and is energy efficient as compared to centralized and distributed techniques. Certain clustering techniques used now a days are LEACH, HEED, T-LEACH and EECS etc. 2.4 Anchor based positioning In this technique, the position of the unknown node (static or dynamic) is determined with respect to anchor nodes[10]. The anchor nodes are nodes who already knows their location in the network by using positioning system known as GPS receiver. Presence of anchor nodes increases 11

6 the accuracy in determining the positions of unknown nodes in the networks. But deployment of sensor nodes is very difficult task specially in unfriendly terrains and harsh environments. In these kind of locations, the sensors are deployed using air planes. Moreover some areas like underwater or underground are unreachable to GPS because of non line of sight communication between nodes and GPS satellites. So applications which are based on GPS for estimating position of anchor nodes determines inaccurate locations of unknown nodes. Due to complexity and inaccuracy in deployement of anchor nodes, many researchers are working on algorithms that are not dependent on anchor nodes for estimation of positions of unknown nodes and these techniques are called anchor free techniques. 3. Routing Protocol 3.1. Sensor Protocols for Information through Negotiation (SPIN) SPIN is basically a resource-adaptive protocol which overcomes the data overlapping problem occurs in flooding protocol. SPIN protocols family contains 2 protocols named as SPIN-PP and SPIN-EC. These protocols are based on resourceadaptive and information negotiation algorithm. They distribute information rapidly and efficiently among sensors in a WSN which enables quick query and response phenomenon among nodes. These Protocols uses a data descriptors, called meta-data for naming of their data. This meta data completely describes the information contained in their collected data. This meta-data is firstly broadcast in the whole WSN and then the whole collected data is transmitted only to the nodes who requests for that data. So negotiations are used for the elimination of the redundant data from the whole network[12]. SPIN protocols exchange data between nodes in 3 steps. Step 1. An ADV message is transmitted for the advertisement of particular metadata by the transmitter node. Step 2. A REQ message is transmitted to request the particular data by the receiver. Step 3. A DATA message that includes actual data is transmitted to the receiver. SPINPP protocol uses negotiation to remove the disintegration and intersection problem. It requires 3 times lesser energy in comparison with flooding protocol and its data distribution speed matches its theoretical value, whereas SPIN-EC s, data distribution speed is 1.5 times more than flooding Geographic and Energy-Aware Routing (GEAR) A position and energy efficiency based routing protocol named GEAR has been projected in which sensors have information about their residual energy as well as the positions[13]. Moreover sensors are also aware about residual energy of each of their neighbors. In GEAR, the sensors are already equipped with localization hardware e.g. a GPS unit for their localization information. Furthermore, the GEAR protocol uses energy aware algorithm which has two phases of broadcasting a data packet in the target region and it is totally based on localisation information of the sensors. In Phase 1, GEAR uses a localisation and energy conscious neighbor selection technique which directs the data packet to 12

7 the target region. Before directing data packets, there are 2 cases needed to be checked :- Case 1 Presence of nodes which are closer to the target region: GEAR selects a node as next hop which is closest to the destination among all nodes. Case2 When maximum nodes are quite far from target: In this case, GEAR chooses a node as next-hop node which minimizes the cost value of the network. Selection of these nodes can be updated according to their cost value. In phase 2 when the packet has reached the destination, it is spreaded in that area by using either restricted flooding method or recursive geographic forwarding. Restricted flooding performs good in case of low density sensor networks[15]. Whereas in high density sensors networks, recursive geographic flooding has higher energy efficiency than restricted flooding. So to overcome this, whole destination area is divided into four sub areas and equal copies of packets are created and forwarded in these subareas. This dividing and forwarding of data packets continues until the regions are left which contains only single node. 3.3 Directed Diffusion (DD) Directed Diffusion is a data-oriented model. A sensor generated data is named according to its attribute by attribute value pairs. Request query is generated by the node that demands the data and interest of that node is specified in that request message based on the application[13,15]. The sink node shoot up an interest query in the network for every application task. The interest cache doesn t have the information about the sink node which basically generates and transmit the interest message but it is updated with the information of one hop neighbor from which it receives the interest query. The interest cache and data cache of the nodes are updated with the interest query and data messages received within the network. On getting these messages, the nodes create a reply link named as gradient towards the one hop neighbor. Gradient link specifies about the data rate, data duration, expiration time and direction in which data is feedbacked in response to the interest message. 3.4 SPAN It is a routing protocol which is applied in a WSN with a goal to make nodes more energy efficient[11]. Span is based on sensor node s energy efficiency as wireless network interface of a node is basically the single largest consumer of energy[16]. So, it would be beneficial to switch the radio off when node is neither receiving or transmitting data. In Span protocol, sensors act as coordinator if two neighbors of a noncoordinator node cannot reach each other directly or through one or two coordinators. When it is used with a geographic forwarding protocol, each sensor advertises its status (i.e., coordinator or noncoordinator), its other coordinators and neighbours. Moreover, after receiving a packet, the coordinator transfer that packet to a node nearby to the receiver. 3.5 Threshold Sensitive Energy Efficient Sensor Network Protocol (TEEN): TEEN [11,14] is a type of hierarchical protocol, in which wireless sensors groups together into clusters. Each cluster s operation is controlled by a cluster head(ch) of that cluster. It sends collected data to the other CH s till the data delivers to the sink node. Thus, the sensor network 13

8 architecture in TEEN is based on a hierarchical grouping of sensor nodes and is designed for real time sensing applications. In TEEN, the data transmission frequency is quite low i.e data transmission occurs only when nodes receive a threshold value (hard threshold) or a change in threshold value(soft threshold) from the cluster head. The limitation of TEEN protocol is that, the nodes will never communicate with each other, if the thresholds are not received, and the user is unable to retrieve data from the network at all[16]. This drawback is removed by another protocol of TEEN family named as APTEEN. APTEEN is basically a clustering-based hybrid routing protocol that allows periodical transmission of sensed data and react to any rapid variation in the value of the sensed element by propagating the corresponding values to their channel heads. The architecture of APTEEN is similar to TEEN, which is designed on the basis of model of hierarchical clustering for proper Communication in source sensors and the sink node. APTEEN offers a flexibility to user by allowing them to configure the time interval and the threshold values of the other parameters. Moreover it assures lesser energy dissipation and enhances lifetime of sensors. Different routing protocols can be used according to the requirement of application of WSN. Table 1 shows the tabular classification and comparison of multiple routing protocols with respect to multiple network efficiency based parameters. This comparison will be quite useful for the wireless sensor network developers in future. 5. Conclusion and future scope The leading challenge in the design of localization techniques and routing protocols for WSN is energy efficiency because of the rare energy resources available with the sensors. The main portion of energy is consumed during communication of nodes. So the foremost objective of all researchers while designing these techniques and routing protocol should be is to extend the lifetime of individual sensors and network as well. This paper surveys various recent localization techniques and routing protocols for WSN and shows a tabular variations in terms of classification, mobility, position awareness, power usage etc of different routing protocols. This paper also includes study of various performance metrics of WSN. 4. Comparison 14

9 REFERENCES 1. D. Estrin et.al, Localiztion in Sensor Networks, University of Califonia, Los Angeles. 2. M. A. Arshad et.al,, Classification of Localization Algorithms for Wireless Sensor Network: A Survey, 2012 International Conference on Open Source Systems and Technologies (ICOSST), pp Mariam Akbar and Nadeem Javaid Efficient Data Gathering in 3D Linear Underwater Wireless Sensor Networks Using Sink Mobility Sensors 2016, 16, WANG Yu1 et. al Three-Dimensional Ocean Sensor Networks: A Survey Science Press and Springer-Verlag Berlin Heidelberg Song Yuli1 and Zhang Hongdong Wireless Sensor Network 3-D Positioning Method on Energy Efficiency International Journal of Multimedia and Ubiquitous Engineering Vol.10, No.9 (2015), pp Samira Afzal A Review of Localization Techniques for Wireless Sensor Networks J. Basic. Appl. Sci. Res., 2(8) , Sun, C. and J.Xing, Y. Ren, Y. liu, J.Sha, J.Sun, Distributed Grid-based Localization Algorithm for Mobile Wireless Sensor Networks: Advances in Electronic Engineering, Communication and Management (1): Shu, J. and R. Zhang, L. Liu, Z. Wu, and Z. Zhou, Cluster-based 3-dimensional Localization Algorithm for Large Scale Wireless Sensor Networks: Journal of Computers, (4): Mrs.P.D.Patil1, Dr(Smt).R.S.Patil2 Distributed Localization in Wireless Ad-hoc Networks ISSN: , ISBN: , PP: Priya and Amita malik A Review on Localization Algorithms in Wireless Sensor Networks International Journal of Computer Science & Engineering Technology (IJCSET) ISSN : Vol. 5 No. 06 Jun Jamal N. Al-Karaki Ahmed E. Kamal Routing Techniques in Wireless Sensor Networks: A Survey Dept. of Electrical and Computer EngineeringIowa State University 12. Geetu and Sonia Juneja Performance Analysis of SPIN and LEACH Routing Protocol in WSN International Journal Of Computational Engineering Research (ijceronline.com) Vol. 2 Issue. 5 Issn (online) September Neha Rathi et.al A REVIEW ON ROUTING PROTOCOLS FOR APPLICATION IN WIRELESS SENSOR NETWORKS International Journal of Distributed and Parallel Systems (IJDPS) Vol.3, No.5, September Parvathi C1, Dr. Suresha2 Existing Routing Protocols for Wireless Sensor Network A study International Journal of Computational Engineering Research (IJCER) ISSN (e): ,Vol, 04 Issue, 7, July Lovepreet Kaur Energy-Efficient Routing Protocols in Wireless Sensor Networks: A Survey International Journal of Computer Applications ( ) Volume 100 No.1, August Shio Kumar Singh et al Routing Protocols in Wireless Sensor Networks A Survey International Journal of Computer Science & Engineering Survey (IJCSES) Vol.1, No.2, November