supervisor Dr.shiri

prepare Ahmed Altememe

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Network architectures and protocols are important aspects in the design of wireless sensor networks (WSNs).

has a big impact on the energy consumption and thus the operational lifetime of the whole network.

It requires a suite of network protocols to implement various network control and management functions.

for example, synchronization, self - configuration, medium access control, routing, data aggregation, node localization, and network security.

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A sensor network typically consists of a large number of sensor nodes densely deployed in a region of interest.

one or more data sinks or base stations that are located close to or inside the sensing region.

the sink(s) also serves as a gateway to outside networks for example Internet.

It collects data from the sensor nodes sends relevant information (or The processed data) via the Internet to the users who requested it or use the information.

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To send data to the sink, each sensor node can use single - hop long – distance.

long - distance transmission is costly in terms of energy consumption.

the energy consumed for communication is much higher Than that for sensing and computation.

For example, the energy consumed for Transferring one bit of data to a receiver at 100 m away is equal to that needed To execute 3,000 instructions .[2]

The ratio of energy consumption for communicating 1 bit over the wireless medium to that for processing the same bit could be in the range of 1,000 –10,000 [3,4] .

the energy consumed for Transmission dominates the total energy consumed for communication and the Required transmission power grows exponentially with the increase of transmission distance.

it is desired to reduce the amount of traffic and transmission distance in order to increase energy savings and prolong network lifetime.

Multihop short - distance communication is highly preferred .

a sensor node transmits its sensed data toward the sink via one or more intermediate nodes

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The architecture of a multihop network can be organized into two types:

Flat architecture.

Hierarchical architecture.

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each node plays the same role in performing a sensing task and all sensor nodes are peers

data gathering is usually accomplished by using data - centric routing

it is not feasible to assign a global identifier to each node in a sensor network.

only the sensor nodes that have the data matching the query will respond to the sink

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sensor nodes are organized into clusters.

the cluster members send their data to the cluster heads while the cluster heads serve as relays for transmitting the data to the sink.

A node with lower energy can be used to perform the sensing task.

send the sensed data to its cluster head at short distance.

This process can not only reduce the energy consumption for communication, but also balance traffic load

improve scalability when the network size grows.

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The major problem with clustering is how to select the cluster heads

there are many clustering strategies.

According to the distance between the cluster members and their cluster heads.

According to the number of tiers in the clustering hierarchy.

A sensor network can be organized into a single - tier clustering architecture or a multitier clustering architecture.

To address the clustering problem, a variety of clustering algorithms have been proposed in the literature

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WSNs are application specific.

According to different criteria.

WSNs can be classifi ed into different categories:

Static and Mobile Network.

Deterministic and Nondeterministic Network.

Static - Sink and Mobile - Sink Network.

Single - Sink and Multisink Network.

Single - Hop and Multihop Network.

Self - Reconfi gurable and Non - Self - Confi gurable Network.

Homogeneous and Heterogeneous Network.

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The application layer contains a variety of application - layer protocols to generate various sensor network applications.

The transport layer is responsible for reliable data delivery required by the application layer. (end-to-end data delivery between sensor nodes and the sink(s)) .

The network layer is responsible for routing the data from the transport layer.

The data link layer is primarily responsible for data stream multiplexing, data frame transmission and reception, medium access, and error control.

The physical layer is responsible for signal transmission and reception over a physical communication medium, including Frequency generation, signal modulation, transmission and reception, Data encryption, and so on.

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Network architectural design has a big impact on the energy consumption and thus the operational lifetime of a WSN.

sensor networks require a new suite of network protocols to perform various network control and management functions,

This chapter gave an introduction of fundamental concepts on network architectures and protocol stack for sensor networks.

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[1] Ian F. Akyildiz et al., “ A survey on sensor networks ” , IEEE Communications Magazine vol. 40 , no. 8 , Aug. 2002 , pp. 102 – 114 .

[2] G. Pottie and W. Kaiser , “ Wireless integrated sensor networks (WINS) ” , Communications of the ACM vol. 43 , no. 5 , May 2000 , pp. 51 – 58 .

[3] J. Hill , R. Szewcyk , A. Woo , D. Culler , S. Hollar ,and K. Pister , “ System architecture directions for networked sensors ” , in Proceedings of 9th International Conference on Architectural Support for Programming Languages and Operating Systems (ASPLoSIX) , Cambridge, MA , Nov. 2000, pp. 93 – 104 .

[4] W. M. Merrill , K. Sohrabi , L. Girod , J. Elson , F. Newberg , and W. Kaiser , “ Open standard development platforms for distributed sensor networks” , in Proceedings of SPIE— Unattended Ground Sensor Technologies and Applications IV (AeroSense 2002) , vol. 4743, Orlando, FL , Apr. 2002 , pp. 327 – 337 .

[5] J. N. Al - Karaki and A. E. Kamal , “ Routing techniques in wireless sensor networks: survey ” , IEEE Wireless Communications , vol. 11 , no. 6 , Dec. 2004 , pp. 6 – 28

[6] R. Rajagopalan and P. Varshney , “ Data - aggregation techniques in sensor networks:A survey ” , IEEE Communications and Surveys and Tutorials , vol. 8 , no. 4 , 4th Quarter 2006 , pp. 48 – 63 .

[7] A. A. Abbasi and M. Younis , “ A survey on clustering algorithms for wireless sensor networks ” , Computer Communications , vol. 30 , nos. 14 – 15, Oct. 2007 , pp 2826 – 2841 .

[8] G. Gupta and M. Younis , “ Load - balanced clustering of wireless sensor networks ” , Proceedings of 2003 IEEE International Conference on Communications (ICC ’ 03) Anchorage, AK , May 2003, pp. 1848 – 1852 .

[9] S. Bandyopadhyay and E. J. Coyle , “ An energy effi cient hierarchical clustering algorithm for wireless sensor networks

[10] W. Heinzelman , A. Chandrakasan , and H. Balakrishnan , “ An application - specifi c protocol architecture for wireless microsensor networks ” , IEEE Transactions on Wireless Communications , vol. 1 , no. 4 , Oct. 2002 , pp. 660 – 670 .

[11] O. Younis and S. Fahmy , “ Heed: A hybrid, energy - effi cient, distributed clustering approach for ad - hoc sensor networks ” , IEEE Transactions on Mobile Computing , vol. 3 , no. 4 , Oct. – Dec. 2004 , pp. 366 – 379 .

[12] P. Wang , C. L i, and J. Zheng , “ Distributed minimum - cost clustering protocol for underwater sensor networks (UWSNs) ” , in Proceedings of 2007 IEEE International Conference on Communications (ICC ’ 07 ), Glasgow, UK , June 2007 , pp. 3510 – 3515 .

[13] S. Banerjee and S. Khuller , “ A clustering scheme for hierarchical control in multi – hop wireless networks ” , in Proceedings of IEEE INFOCOM ’ 01 , Anchorage, AK , Apr. 2001 , pp. 1028 – 1037 .

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