Design and Development of an Energy-Efficient Node Address Assignment Algorithm for Large Scale Wireless Sensor Networks

1. Introduction:

Tremendous advancement in the field of wireless communication, microelectronics and IC fabrication have led the development of tiny sensors with sensing, computation and communication capabilities. These sensor nodes deployed densely close to the physical environment, organized into a network (WSN) collaboratively perform some distributive task. These sensor nodes can sense, measure and gather information from environment (temperature, pressure or humidity etc.) and transmit the sensed data to the sink (or user) where the specific application resides[1][2][3]. Sensor nodes are devices contains the four main components showing in figure 1 that includes:

A sensing (one or more sensor) and actuation unit. A processing unit (limited computing capability compared to traditional computer) A communication unit(short range) A power unit (battery)

Figure1: Typical sensor node

A wide variety of applications of WSN are possible. These may be categorized as event detection, tracking and monitoring. Usually WSN have been used in high-end application such as radiation and nuclear-threat detection systems, weapon sensors for ship, biomedical application, habitat sensing and seismic monitoring. In recent times, sensor networks are used in networked biological and chemical sensors for national security application [1]. Furthermore, it can be applicable to direct consumer application. Existing and potentials applications of sensor networks include, among others, military sensing, physical security, air traffic control. traffic surveillance, video surveillance, industrial and manufacturing automation, distributed robotics, weather

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sensing, environment monitoring, national border monitoring, building and structure monitoring, vehicle tracing and detection, tracking and monitoring doctors and patients inside a hospital, elderly assistance, automated meter reading, precision agriculture, forest fire detection etc.

Example of a typical wireless sensor network is shown in following figure 2:

Figure 2: Typical Wireless sensor network

Individual sensors can do very little of their task but large number of sensors can be harmonized into a planned network to carry out a big sensing task. Sensors are mainly battery-powered, and when deployed they remain in the subject area unattended for long time. Battery can hardly be re-energized or replaced in case of power drain-out. So sensors are instinctively constrained by energy. They do not transmit signal to a very long distance to reach a remote sink, rather they form a multi hop communication scenario with their short range radio equipments to conserve energy and transmitting data each time to the immediate neighbors and thus fusing it into the entire network.

Node Address assignment ensure the identity of a sensor node in the network so that sensors communicate with its sink and vice versa. In fact, most of the routing protocols need a network wide unique sensor node address in order to exchange data among sensor nodes. Node addresses are also required for some administrative task such as configuring and monitoring of individual nodes, downloading binary code to sensor nodes etc. But, Due to energy constraint and particular

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data reporting manners of sensor nodes, address assignment problem for sensor network is notably different from that of for traditional network. For example, the Berkeley Motes have a default fixed packet size of 36 bytes. Suppose the MAC address of 48 bits is applied and packets carry only the source and destination node IDs in their header. It results in an effective payload of, at most, (36 -12) =24 bytes which is less than 70% of packets size [12]. In IEEE 802.15.4, the frame length is limited to 127 byte due to its low bit rate [14]. 32 bits (4 bytes) IPv4 or 128 bits (16bytes) IPv6 addresses are impractical because they have 20 bytes and 40 bytes of overhead respectively.Moreover, sensor nodes are deployed randomly in remote and mainly unattended. So, fault tolerance and scalability is very important for node address assignment. Here, Fault tolerance is the correct address assignment even though various fault such as duplicate assignment of the same address, assigning multiple addresses to the same node or address loss happen. Scalability refers to the ability to adapt the address assignment in case of topology change or a number of nodes added in the network.

The rest of the proposal is organized as follows: In Sec. 2, brief reviews of the existing node address assignment techniques used in wireless sensor networks are discussed. In section 3, open issues are highlighted. Then, in section 4-8, sequentially describes the problem statement and significance, scope, objectives of the research, methodology used in this research and expected outcome of the research.

2. Related Works:

The main task of Wireless Sensor Network (WSN) nodes are to sense and collect data from a target domain, process the data and transmit the information back to the specific sites where the underlying application resides. Thus the communication paradigm is mainly many- to-one that is source node to sink node. There is infrequent need to communicate between two distant nodes. Moreover, since the payload length in the data packet is usually small, it wastes bandwidth and power if the data are encapsulated in a TCP/UDP/IP packet. Thus, customized network protocols are adopted instead of TCP/IP to save the communication overhead and energy consumption.

There are several mechanism proposed for node addressing problem. Dynamic host configuration protocol (DHCP) [4] commonly used for automatically address assignment to internet host. However this is a state full approach and suffers from heavy control overhead which is not fit for wireless sensor network.

Muneeb Ali et al [5], proposed a cluster based locally unique address assignment scheme for sensor networks. Nodes are grouped into some disjoint clusters and nodes in the same cluster are given local addresses that are unique within the cluster. Address reuse is possible among different

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clusters. Each cluster is assigned a unique address, and clusters are arranged logically in some hierarchy. When nodes communicate within a cluster, they use their local addresses, but when they communicate amongst clusters, cluster ID is appended with the local addresses. If all cluster IDs along with the local address are combined together for a node, a network wide unique address of that node is generated. However this scheme assumes that cluster formation process is completed at network boot time and those clusters are conserved. This is not applicable when the cluster is changed dynamically like the protocol LEACH [6].

Pal Chaudhuri et al. in [7] proposed a global unique method of address allocation named TreeCast. In this technique, nodes are organized in a tree structure. Sink node is the root of the tree. The parent address and a random address combine to a child’s address, and the parent address is a prefix address. Figure 3 shows an example of node address assignment by using TreeCast.

Figure 3: Address allocation by TreeCast.

However, its addressing scheme is only optimized for a single sink node. To support multiple sink nodes, the algorithm requires multiple addresses per node, each of which is originated from individual sink node.

Uddin et. al in [8] proposed another global addressing technique for wireless adhoc network based on hierarchical numbering. This technique is similar to TreeCast but utilizing the address bit more efficiently. In TreeCast, the address size is increasing as depth of the tree increases. Unlike this, here first tree is constructed then a post order traversal of the tree is made from sink.And a unique number is assigned in each node. Sink initiate the traversal, so it get the highest number. It can be shown that , for network size N, log2 [N] bit is enough for assigning unique address to each node. Figure 4, shows an example of hierarchical numbering.

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However, if the network topology changes, the algorithm need to execute again and the entire node address will be changed.

Figure 4: Address allocation by Hierarchical numbering. The ZigBee[9] standard adopts a fully decentralize addressing scheme called DAAM (Distributed address assignment mechanism) which employs an algorithm C-skip (child skip) where addresses are assigned with a parent-child relationship that forms a symmetrical tree.16 bits are used as a node address. In this mechanism, the router or coordinator should have priory knowledge about the maximum number of children that a parent node can have (Cm), the maximum depth of the network (Lm) and the maximum number of child routers of a parent node (Rm). C-skip(d) is an offset that a parent node distributes address to child node. The calculation of C-skip(d) is :

C-skip(d) = 1+ Cm × (Lm − d − 1), if Rm = 1

(1+Cm−Rm−Cm×RmLm−d−1 ) --------------------- (1)-------------------------------------- ,otherwise.

(1 – Rm )

Where d is the network depth.

The child node address is assigned by the following equation:An = Aparent + Cskip(d) × Rm + n, 1 ≤ n ≤ Cm, ------------------------------------------- (2)And child router address is assigned by:An = A parent + (n-1) * Cskip(d) + 1 ; --------------------------------------------(3)

An example of ZigBee address assignment is shown in figure 5 where Cm =4, Rm = 4 and Lm =3:

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Figure 5: An address assignment example is ZigBee network.

The address assignment in ZigBee is very efficient due to its fully distributive nature which imposes a very low overhead cost. However it is inflexible because it is static. Moreover, it suffers from some problem like address wasting, room shortage, and route detour [10]. If a node already used up its address segment, it cannot accept any new node to join though a chunk of free address is available to other nodes. In addition, C-skip scales only up to depth 5.

In [11] a token based scheme is proposed where a special node is assigned to a token holder, which takes in charge of address allocation to new node. However, every node in the networks should keep track of the latest address of the holder.

Jialiu Lin et al in [12] proposed a variable length field-wide unique ID scheme where first construct a overlay binary tree and each position of tree was mapped to a unique ID and assigned to a node. However it does not minimize the control overhead.Jun Zhan et al in [13] also proposed a variable length dynamic addressing (VLDA) based on network traffic distribution. VLDA assigns shorter address to busy node and longer address to idle nodes and thus obtain the energy efficiency.However, if the traffic pattern altered or network topology changed frequently, these methods suffer from heavy control overhead.

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3. Open Issues:

Node address assignment in wireless sensor networks has attracted a lot to the researchers in the recent years and introduced unique challenge compared to mobile ad hoc network and traditional wired network due to its specialized characteristics like energy constrain and data communication paradigm .Many important issues need to be examined regarding address assignment such as address space length, fixed or variable, storage cost of allocation table, locally unique addresses or globally unique addresses, address reusing, network partition and merge supporting, and security consideration.

The most important research issue is that develop an energy efficient , scalable, self organized and fault tolerant node address assignment algorithm for large scale wireless sensor network.

In addition, there is a need to develop QoS aware addressing algorithm which can ensure guaranteed delay for real time applications. Currently, there is very little research that looks at handling QoS requirements in a very energy constrained environment like WSNs.

Moreover, sometimes a sensor node needs to communicate with the outside network like internet. So a node addressing technique that Integrate Wireless Sensor Network with Internet also an interesting area to explore.

Addressing mechanisms are susceptible to a number of attacks. Ensuring network integrity, mitigating DoS attacks, “Man-in-the-middle” attacks is also an important research issue for node address assignment in wireless sensor network.

4. Problem Statement and Significance:

Wireless sensor networks have been gaining increasing demand in many sectors all over the world. However, there is a growing concern when the size of the network becomes large because IP-based addressing techniques are impractical and too costly due to its large packet overhead. A number of researchers have proposed solutions to the problem of energy-efficient node address assignment for large scale networks. This problem is multidimensional in the sense that a hybrid of multiple addressing techniques must be used in order to effectively solve the problem. Thus, the need for developing a novel energy-efficient node addressing scheme for large scale wireless sensor networks that incorporates multiple feature of addressing techniques.

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5. Scope:

This research will focus on only node address assignment in network layer and assumed full support will get from the other layers. In this research we will study different node address assignment algorithm or techniques used in wireless sensor network to identify opportunity for further enhancements, design an enhanced energy efficient, scalable and fault tolerant address assignment algorithm and evaluate the performance of the strategy. Also security mechanism of wireless sensor network will not consider in this specific research.

6. Research Objectives:

The major objective of this research is to develop an energy efficient node address assignment:

To identify limitations of existing node address assignment algorithms or techniques used in wireless sensor network.

To develop energy efficient node address assignment algorithm that will be suitable for large scale Wireless sensor network.

To reduce the packet and control overhead. And Comparative performance evolution of this proposed algorithm.

The major objective of this research is to develop an energy efficient node address assignment techniques that will suitable for large scale wireless sensor network. These are the sub objectives:

To develop an efficient scheme that will be reduce the packet and control overhead in the network.

To analyze the performance of the proposed techniques and benchmark with the standard method.

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7. Research Methodology:

8. Expected Outcomes:

An energy efficient scalable and fault tolerant node address assignment algorithm for large scale wireless sensor network.

Journal paper and conference paper. Master’s thesis

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Literature review on Wireless sensor network, its application and opportunity.

Study existing node address assignment algorithm used in wireless sensor network.

Identify the limitation of existing node address assignment algorithm.

Develop a new energy efficient node address assignment algorithm which overcomes the limitation

of the existing techniques.

Simulation and performance evaluation of the proposed address assignment algorithm.

Tools: NS2

9. Research Milestone:

Project Activities Aug10

Sep10

Oct10

Nov10

Dec10

Jan11

Feb11

Ma11

Apr11

May11

Jun11

Literature review on WSN, its application and opportunity.Study on existing Node address assignment techniquesComparative analysis of these algorithmDevelop a new algorithm to meet the research objectivesImplementation and simulationAnalyzing the simulation result and benchmarking Documentation and report writing

10. References:

[1] Kazem Shohraby, Daniel Minoli, Taieb Znati, Wireless Sensor Networks, technology, Protocol and Applications, John Wiley & Sons,2007

[2] R.Verdone, Dardari, Mazzini, A.Conti, Wireless Sensor and Actuator Networks; Elsevier: London, UK, 2008.

[3] Ameer Ahmed Abbasi, Mohamed Younis, A survey on clustering algorithms for wireless sensor networks, Computer Communications 30 (2007)2826–2841.

[4] R. Droms. "Dynamic Host Configuration Protocol", RFC: 2131, (March 1997).

[5] M. Ali and Z. A. Uzmi, "An Energy-Efficient Node Address Naming Scheme for Wireless Sensor Networks", IEEE International Networking and Communication Conference INCC'04, 2004.

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[6] W.Heinzelman. Application-Specific Protocol Architectures for Wire-less Networks. Ph.D. thesis, Massachusetts Institute of Technology,2000.

[7] S. P. Chaudhuri, S. Du, A. K. Saha, and D. B. Johnson, "TreeCast: a stateless addressing and routing architecture for sensor networks," in Parallel and Distributed Processing Symposium, 2004. Proceedings. 18th International, 2004, p. 221.

[8] Md. Yusuf Sarwar Uddin, Mohammad Ashiqur Rahman and Md.Mostofa Akbar, "Hierarchical Numbering Based Routing Protocol for Wireless Ad hoc Networks", Proc. of 1st International Conference on Next Generation Wireless Systems 2006 (ICNEWS06), Dhaka, pp. 345-349, January 2006.

[9] ZigBee 2006, ZigBee Alliance. http://www.zigbee.org

[10] Li-Hsing Yen ,Wei-Ting Tsai, The room shortage problem of tree-based ZigBee/IEEE802.15.4 wireless networks, Computer CommunicationsVolume 33, Issue 4, 1 March 2010, Pages 454-462.

[11]S.Kim, J.Lee, and I.Yeom, “A token-based dynamic address allocation protocol for mobile adhoc networks,” Tech. Rep., Computer Science, KAIST, Seoul, Korea, 2005.

[12] Jialiu Lin,   Yunhuai Liu ,  Lionel M.Ni,SIDA: Self-organized ID Assignment in Wireless Sensor Networks, IEEE international conference on Mobile adhoc and Sensor system(MASS), 2007

[13] Jun ZHAN, Bo YANG, Aidong MEN, Variable length dynamic addressing based on network traffic distribution in wireless sensor networks, Front. Electr. Electron.Eng. China 2010, 5(1):43–48.

[14] RFC 4944, Transmission of IPv6 packets over IEEE 802.15.4 Networks, http://tools.ietf.org/html/rfc4944

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