Graduate Project Presentation

TCET.797.01

Presented By – Braj Raj Singh

Telecommunication Engineering Technology

Efficient Data Aggregation from polling points

in Wireless Sensor Network

Background-

Existing System-A number of approaches exploiting sink mobility for data collection in wireless sensor networks have been proposed in recent years.

• In single hop communication, we can minimize energy consumption, however, at the expense of high data delivery delay.

• In the second solution, this delay is low but the energy consumption due to multi hop communication is rather high.

Proposed System-

Our proposed protocol aims at minimizing the overall network overhead and energy expenditure associated with the multi hop data retrieval process while also ensuring balanced energy consumption among sensor nodes and prolonged network lifetime. This is achieved through building cluster structures consisted of member nodes that route their measured data to their assigned cluster head (CH). Clustering has proven to be an effective approach for organizing the network in the above context. Besides achieving energy efficiency, clustering also reduces channel contention and packet collisions, resulting in improved network throughput under high load.

WIRELESS SENSOR NETWORK (WSN)

1

Wireless Sensor Network

A Collection of Spatially Distributed Organized autonomous sensor nodes that collects data from its surrounding.The Wireless sensor network is a combination of wireless sensing and data networking that consists of protocols and algorithms with self-organizing capabilities and can be used in safety-critical or highly reliable applications

Important Characteristics-

• Scalability and Reliability• Self-Configurability• Flexible Topology Changes

• Self-organized

• No wired infrastructure

• Potential multi-hop routes

• Ability to withstand in harsh environmental conditional

Applications of WSN-

The Military Applications

The Medical Applications

Environmental Monitoring

Target tracking Industrial

Application Infrastructureand protection

application

Topology of Wireless Sensor Network

• Point to point (Peer to Peer) topology- In this type of network topology nodes are involved in direct node-to-node communication without going through centralized communication hub. Each peer is able to work as either client or server.

• Star topology- In star topology, each node must communicate through a centralized connected hub. Information cannot be directly routed through node-to-node .The centralized hub works as server and connecting nodes works as clients.

• Tree based topology- In a tree based topology, the centralized node functions as root node. A root node has a central hub that is one step down in hierarchy. This lower level then forms a star based network, which is why a tree network is also called hybrid network.

• Meshed Network topology- Mesh networks have a self-healing property because it allows data to hop from node to node. This type of network is very complex as compared to other topologies and is more cost effective.

Architecture of Wireless Sensor Network

Wireless sensor network composed of two distinct layers

• Sensor and Networking layers• Distributed Service layer

Key component of Sensor Network-

1. Sensor Nodes (SN)

2. Cluster Head (CH)

3. Mobile Collector (MS)

4. Rendezvous Nodes /Polling Points

5. Base Station

1.Sensor Node

Processing Unit

(microcontroller/microprocessor)

Sensing Unit (A/D convertor)

Power supply (battery)

Communication Unit (radio trans-receiver)

PowerSupply

Microcontroller

AnalogtoDigital

Convertor

S1 S2

ExternalMemory

Transreceiver

2. Cluster Head ( CH)

In wireless sensor network, small group of sensor node formed a cluster and each cluster has a coordinator referred Cluster head (CH). Cluster head selection has impact on network lifetime. Cluster Head should be reachable in a single hop from their cluster members.

Primary function of Cluster head –

Aggregate data from respective sensor node and transferred to remote processing element.

Localization of network traffic. CH implement network management

strategy to enhance network operation and prolong the battery life.

Reduce the rate of energy consumption by schedule activity activities in the cluster so sensor node can switch to low power sleep mode

3. Mobile collector

Mobile Collector

Data Collector (Sink) can be classified in two category-

Static Collector- Network sink nodes are on fixed position; either close or inside the sensing region that makes network simpler to control.

Mobile Collector-The Mobile Collector (MC) moving through the network deployment region can collect data from the static sensor nodes over a single hop radio link when approaching within the radio range of the sensor nodes or with limited hop transfers if the sensor nodes are located further.

Mobility pattern of Data collector-a) Randomb) Predictable (their movement pattern is known before hand)c) Controlled (their movement is actively controlled in real time)

4. Polling Points /Rendezvous Nodes-

• Polling points guarantee connectivity of sensor clusters with Mobile collector. Their selection largely determines network lifetime.

• Polling points are selected among candidate Sensor node typically located in the periphery of the sensor island and lie within the range of mobile collector.

• Suitable polling points are those that remain within the Mobile collector range for• relatively long time, in relatively short distance from the sink's trajectory and have

sufficient energy supplies.

Polling Point

Sink Trajectory

5. Base Station

The base stations are one or more components of the WSN with more computationalenergy and communication resources. They act as a gateway between sensor nodes and the end user as they typically forward data from the wireless sensor network on to a server.

CLUSTERING MECHANISM2

Clustering

Clustering is a process of logical grouping of similar sensors to achieve load balancing and network scalability . Clustering is an effective approach for organizing the network that reduces channel contention, packet collision and improved network throughput under high load.

ClusterHead

MobileSink

DataAggrega on

ClusterHeadElec on

ClusterForma on

SensorNodes

SensoryData

Clusterforma onandDataCollec onapproachbyMobileSinkfromSensorNodes

Clustering Objectives

Support Network Scalability

Decrease energy consumption through data aggregation

Limits data transmission (load balancing)

Facilitate the reusability of the resources

Conserve communication bandwidth

Cluster Head and gateway nodes can form a virtual backbone for inter-

cluster routing

Cluster structure gives the impression of a smaller and more stable

network

Improve network lifetime

Reduce network traffic and the contention for the channel

Data aggregation and updates take place in CHs

Types of Clustering

Cluster Communication

Clustering support network scalability and reduces energy consumption through efficient data aggregation. It can localize the route setup with in the cluster and thus reduce the size of routing table that help to stabilize network topology. Cluster communication can be classified as-

CH

CH

CH

BaseSta on

Intra-cluster

Inter-cluster

BaseSta on

SensorNodesDeployedinaRegion

Sensorinforma onforwardingwithoutclustering–SinglehopMechanism

BaseSta on

SensorNodesDeployedinaRegion

Sensorinforma onforwardingwithoutclustering–Mul -hopMechanism

SensorNodes

BaseSta on

SensorNodesDeployedinaRegion

Sensorinforma onforwardingwithclustering–SinglehopMechanism

ClusterForma on

ClusterHead

SensorNodes

BaseSta on

SensorNodesDeployedinaRegion

Sensorinforma onforwardingwithclustering–Mul -hopMechanism

ClusterForma on

ClusterHead

SensorNodes

ROUTING 3

Routing

Routing has two main function- Route Discovery and Packet forwarding .

The major requirements of a routing protocol-

• Minimum route acquisition delay

• Quick route reconfiguration in the case of path breaks.

• Loop-free routing

• Distributed routing protocol

• Low control over-head

• Scalability with network size

• QoS support as demanded by the application

• Support of time-sensitive traffic and

• Security and privacy

Types of Routing -

Rou ngProtocol

Flat Hierarchic

Proac ve Reac ve

DSDV AODV/DSR

Proactive Vs. Reactive-

Proactive (Table Driven) Reactive (On- Demand)

Route from each node to every other node in the network

Routes from Source to Destination only

Routes are ready to use instantaneously Routes constructed when needed, higher connection setup delay

Periodic route-update packets Route update when necessary

Changes to network topology immediately propagated

Changes to network topology not propagated immediately

Large routing tables Small or No routing tables

AODV Routing Protocol

Reactive or on Demand

Uses bi-directional links

Route discovery cycle used for route based on requirement

Sequence numbers used for loop prevention and as route freshness criteria

Provides unicast and multicast communication

Maintain Active routes.

Whenever routes are not used -> get expired->Discarded

– Reduces stale routes

– Reduces need for route maintenance

AODV Routing Table

In AODV each node maintain a routing table this routing table contains information about reaching destination nodes .The routing table field includes- Destination IP address, destination sequence number, valid destination sequence number flag, Network interface, hop count, next hop, precursor list and life time which is normally route expiration or deletion time

AODV Route Discovery Mechanism

In AODV protocol when a node willing to send a packet to some Destination .It checks its routing table to determine if it has a current route to the destination-

• If Yes, forwards the packet to next hop node• If No, it initiates a route discovery process

❒ Route discovery process begins with the creation of a Route Request (RREQ) packet -> source node

RREQ- route request-RREQ contain most recent sequence number of the destination. RREQ is broadcasted when a node needs to discover a route to its destination. As this message propagate through a network intermediate nodes use it to update their routing table.

❒ Packet also contains broadcast ID number, Broadcast ID gets incremented each time a source node uses RREQ• Broadcast ID and source IP address form a unique identifier for the RREQ❒ Broadcasting is done via Flooding

Route Request Propagation ( RREQ)

Propagation of Route Reply (RREP) message-

When a RREQ reaches a destination node the destination route is made available by Unicast a RREP back to the source route. A node generate RREP if it has an active route to destination. As RREP propagate back to the source node, intermediate nodes update their routing table.

Route Error Message ( RERR)-

RERR is initiated by the node upstream (closer to the source) of the break• Its propagated to all the affected destinations• RERR lists all the nodes affected by the link failure -> Nodes that were using the link toroute messages (precursor nodes)• When a node receives an RERR, it marks its route to the destination as invalid -> Setting

distance to the destination as infinity in the route table❒When a source node receives an RRER, it can reinitiate the route discovery

1. Link between C and D breaks2. Node C invalidates route to D in route table3. Node C creates Route Error message• Lists all destinations that are now

unreachable• Sends to upstream neighbors

Route Maintenance Mechanism-

Node A receives RERR

• Checks whether C is its next hop on route to D

• Deletes route to D (makes distance -> infinity)

• Forwards RERR to S

Node S receives RERR

• Checks whether A is its next hop on route to D

• Deletes route to D• Rediscovers route if still needed

Importance of Sequence Number -

Sequence numbers used for route freshness and loop prevention

To prevent formation of loops• A had a route to D initially• Assume that A does not know about failure of

link C-Dbecause RERR sent by C is lostNow C performs a route discovery for D. Node Areceives the RREQ (say, via path C-E-A)• Node A will reply since A knows a route to D

via node B• Results in a loop (for instance, C-E-A-B-C )

Loop C-E-A-B-CBecause of usage of sequence number, A

will not use the route A-B-C, because thesequence numbers will be lower than what Areceives from A

DSDV Routing Protocol

The DSDV routing protocol is an enhanced version of the distributed Bellman-Ford

algorithm where each node maintain a table that contain the shortest distance and

the first node on the shortest path to every other node in the network.

Routing table updates are periodically transmitted.

To minimize the routing updates, variable sized update packets are used depending

on the number of topological changes.

Each entry in the table is marked by a sequence number which helps to distinguish

stale routes from new ones, and thereby avoiding loops.

When a route update with higher sequence number is received, the old route is

replaced. And when there are two different routes exist with same sequence number

the route with better matrix is used.

DSDV

DSDV adds two things to distance vector routing –

a) Sequence number that avoid loops

b) Damping- hold advertisement for changes of short duration

Each node periodically transmits update that includes own sequence number and

routing table update.

Node also send routing table update for important link changes.

When two to a destination received from two different neighbors –

a) Chose the one with greatest destination sequence number

b) If equal chose the smaller metric (hop count)

DSDV Table structure

Sequence Number- sequence number originated from destination number and it ensures loop freeness.

Install time –when entry was made (Used to delete stale entry from the table)

Stable Data -Pointer to a table holding information on how stable a route is. Used to damp fluctuations in network.The main advantage of DSDV protocol is this is loop free through destination sequence number and there is no latency caused by route discovery. But it has overhead issue because most routing information is never used.

Destination Next Metric Seq. Nr Install Time Stable Data

A A 0 A-550 001000 Ptr_A

B B 1 B-102 001200 Ptr_B

C B 3 C-588 001200 Ptr_C

D B 4 D-312 001200 Ptr_D

Proposed System-Mobi Cluster

MobileSinkTrajectory

BaseSta on1 BaseSta on2

MobileCollector1 MobileCollector2

Cluster

ClusterHead

SensorNodes

PollingPoint/RendezvousNode

System Flow Diagram-

Mobi-Cluster Protocol

Concept-

• Mobi-cluster protocol helps to ensures delivery of data even through multi-hop transfers from source sensor nodes located far from the mobile sink trajectories.

• Building hierarchical cluster structures comprising neighbor sensor node to increase the performance of intra-cluster data filtering and minimize the data relaying overhead.

• Emphasis is given on selecting the appropriate polling points among Sensor nodes located in the periphery of the sensor islands(so that they remain within the range of MSs for sufficient time and they buffer data from balanced-

sized groups of source SNs)

Five stages of Mobi-Cluster Protocol-

1.Cluster Head Selection2. Polling point selection3. Cluster Head attachment to Polling points4. Data Aggregation and forwarding to Polling points5. Communication between Poling point and Mobile collector(data)

ClusteringMechanism

Mobi-ClusterProtocol

2 3 4 51

Ini al3Phaseare-SetupPhase Lasttwophasesaresteadyphase

InSetupphasemobilesinkcompleteasingletripwhilebroadcas ngbeaconmessageperiodically.SensorintheNetworkusedthis‘Beacon’messagetodeterminenumberofimportantparameterforprotocolopera on

InsteadyPhasesensordatarou nelygatheredandsenttomobilesink.Thisphaseincludesreselec onofRendezvousnodesandlocalre-clustering.LocalRe-Clusteringperformedwhensomeimportantnodessufferfromenergyexhaus oncondi on

Overall Flow-diagram

Project Implementation

Simulation Procedure

Implementation is the stage of the project when the theoretical design is turned out into a working system. Thus it can be considered to be the most critical stage in achieving a successful new system and in giving the user, confidence that the new system will work and be effective.

The implementation stage involves careful planning, investigation of the existing system and it’s constraints on implementation, designing of methods to achieve changeover and evaluation of changeover methods. The process of putting the developed system in actual use is called system implementation.

Implementation is the final phase. It involves user training, system testing and successful running of developed system.

Simulation

NS-2 Features

It is a discrete event simulator that is object oriented C++ event scheduler is implemented in the back end OTCL is implemented in front end NS-2 can be used on UNIX as well Windows operating system(

with Cygwin)

Layered Architecture of NS-2

Simula onScenario 1 2

Setns_[newSimulator]Setnode_(0)[$ns_node]Setnode_(1)[$ns_node]

C++Implementa on

ClassMobileNode:publicNode{Friendclassposi onhandler;Public:MobileNode();}

Networkschedulerandnetworkcomponentareimplementedbyc++

LayeredArchitectureofNS2(NetworkSimulator)

Future Approach- Enhance Data Aggregation strategy (Using Remote Agent)

1. PDR2. Throughput3. Residual

Energy4. Delay

COMPARISON BASED ANALYSIS5

PDR ( Packet Delivery Ratio)-

PDR= No of packet received by destination / No of packet sent by content based source

0.00%

20.00%

40.00%

60.00%

80.00%

100.00%

AODV DSDV

PDR

AODV

DSDV

Total Energy Consumption

450

500

550

600

650

AODV DSDV

Total Energy Consumption (Kbps)

AODV

DSDV

Throughput

Throughput calculation provides information about successful data delivery from a receiver to a sender over communication stream; this communication steam can be either logical or physical link .The data transmission calculated in bits per second or kilobits per

second. For efficient network a routing protocol with higher throughput is desirable

AODV DSDV

References-

http://www.mathcs.emory.edu/~cheung/Courses/558-old/Syllabus/90-NS/4-

Wireless/intro.html

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.91.4781&rep=rep1&type=p

df

http://ww2.cs.mu.oz.au/~egemen/lncs08.pdf

http://www.computer.org/csdl/proceedings/anss/2007/2814/00/28140060-abs.html

http://dgavalas.ct.aegean.gr/en/iframe_files/papers/2009/AdHoc-NOW%272009.pdf

http://www.ijettcs.org/Volume1Issue2/IJETTCS-2012-08-23-087.pdf

http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4224182

http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=06360577

http://en.wikipedia.org/wiki/Sensor_node

http://www.me.utexas.edu/~jensen/exercises/mst_spt/mst_demo/mst1.html

http://dgavalas.ct.aegean.gr/en/iframe_files/papers/2009/Clustering-chapter.pdf

http://www.ijettcs.org/Volume1Issue2/IJETTCS-2012-08-23-087.pdf

http://www.ipcsit.com/vol6/57-E022.pdf

http://shodhganga.inflibnet.ac.in/bitstream/10603/4106/13/13_chapter%205.pdf

References-

Rendezvous Planning In Wireless Sensor Networks With Mobile ElementsGuoliang Xing, Member, IEEE, Tian Wang, Student Member, IEEE, Zhihui Xie, andWeijia Jia, Senior Member, IEEE

Sencar: An Energy-Efficient Data Gathering Mechanism For Large-Scale Multi-Hop Sensor NetworksMing Ma, Student Member, IEEE, and Yuanyuan Yang, Senior Member, IEEE

Energy-Efficient Mobile Data Collection In Wireless Sensor Networks With Delay Reduction Using Wireless CommunicationArun K. Kumar and Krishna M. Sivalingam Dept. of Computer Science and Engineering,

Mobile Element Scheduling with Dynamic DeadlinesArun A. Somasundara, Aditya Ramamoorthy, Member, IEEE, andMani B. Srivastava, Senior Member, IEEE

Adaptive Sink Mobility in Event-Driven Densely Deployed Wireless Sensor NetworksZoltán Vincze1, Dorottya Vass1, Rolland Vida1, Attila Vidács1 and András Telcs2

Optimal Speed Control of Mobile Node for Data Collection in Sensor NetworksRyo Sugihara, Student Member, IEEE, and Rajesh K. Gupta, Fellow, IEEE

Joint Mobility and Routing for Lifetime Elongation in Wireless Sensor NetworksJun Luo Jean-Pierre Hubaux

Clustering in Wireless Sensor NetworksBasilis Mamalis, Damianos Gavalas, Charalampos Konstantopoulos, and Grammati Pantziou

Prolonging the Lifetime of Wireless Sensor Networks via Unequal ClusteringStanislava Soro and Wendi B. Heinzelman

Questions