Fayzah Al Shammari 7 Nov,2011 CSI 5148 Wireless Ad Hoc Networking Project Presentation

 Introduction:  The Problem Statement  Location Service Classification Flooding based(Doubling Circle Update) Quorum-based  Localized Distance-Sensitive Service Discovery  Conclusion  References  Questions and Answers.

 Sensor and actuator networks consist of wireless hosts that operate independently with no fixed infrastructure or centralized control.  Node mobility causes frequent unpredictable topological changes  the task of finding and maintaining routes (routing) is nontrivial.  A number of protocols for achieving efficient routing have been proposed.

 The sensor use currently available and inaccurate information on the location of destination and route immediately toward that location, in the hope that the position information would become more accurate as the message approaches region containing destination.

1) The sensor initiates Destination search messages. 2) The destination initiates Path creation messages, upon receiving the first copy of the search messages. 3) The sensor initiates Data traffic messages upon receiving reply from destination containing its exact location.

 Short messages do not have the real information (to be forwarded to destination) as part of them.  Location update, destination search and path creation messages are short messages.  Long messages have the real information as part of them.  Data traffic messages are long messages.

 Component 1: Location update and Actuator search ( survey them )  Component 2: Routing to a destination whose position is known. (Satisfactory localized solutions are already proposed such as GFG)

 mobile actuators  location update messages.  Static sensors  search messages to learn latest position of actuators.  the cost  success rate of finding target actuator.  many ad hoc networks location service (LS) algorithms can be applied directly.

Location service Flooding- based ProactiveReactive Quorum- based FlatHierarchical Home- based FlatHierarchical

Location ServiceProactiveReactive Actuator UpdateFlooding some areas or the entire network periodically. normally does not have Update Actuator Searchdirected to those areas, and it is sufficient that first receiver nodes in the areas respond OR NO actuator search is needed. if a sensor cannot find fresh location of a target actuator, it floods the network with a search message AlgorithmsDoubling circle update, Direction based update, geographic- Routing based update Request Zone Search, Expanding Ring search.

each actuator propagates its location information within circles C(i) of increasing radii 2 R for i = 1, 2, 3,... Each of these circles is associated with a refreshment timer.  Actuator Update: 1. Whenever the timer expires (time-based policy), the actuator broadcasts a location update message within the corresponding circle. 2. whenever the actuator moves outside a circle C(t) for some t (distance- based policy), it broadcasts its location to all the nodes located within a circle of radius 2 t+1 R centered at its current position.  Actuator search (or direct routing to it) then follows these circles of last updates. Sensors (source or intermediate sensors) forward a search message toward the last reported position of target actuator, which since the last report may have moved within the circle of some radius. As the message moves closer to target actuator, its position information becomes more precise, and sensors are able to direct the message toward center of circles with twice smaller radius than previously, until target actuator is eventually reached.

Doubling Circle Update Amouris, Papavassiliou, Li, 1999 S D D’D’ D”D”

Location service Flooding- based ProactiveReactive Quorum- based FlatHierarchical Home- based FlatHierarchical

 Stojmenovic et al. presented this approach.  Update: Each node distributes its current position along a “column” in the network.  Search (wants to discover the location of another node) it searches along a “row” in the network. This row intersects the columns of all the other nodes, thus ensuring discovery.

[Stojmenovic 1999, with Liu and Jia 2006, 2007]

 Less communication overhead compared with flooding based approach as no potentially network wide flooding is used But 1. Location update and search has to cross the entire network. 2. Network boundary has to be included to guarantee intersection. 3. Suffering from large storage load if all node are collinear along column, every node has to store every other’s location.

 Actors offer movement-assisted services to sensor nodes and/or to their monitored environment. They remain static and move only upon request.  The Sensor (Service Consumer)should be able to discover the Actuator (Service Provider).

 Closest service selection(that each service consumer discovers the closest service provider)or nearby (that each service consumer discovers a service provider that is at most twice as far as the closest.  It is a primary concern for energy saving and timely response.

 The service directory (location of all service providers) are distributed in a localized planar structure information mesh by using: 1. Quorum like update/search 2. Blocking rule  The Service discovery is done by a cross lookup, restricted within a mesh cell or the aggregation of several mesh cells.

A B

 A node receiving information from multiple service providers forwards only the information of the closest one.  Adding update deletions for asynchronous networks.

A B

No update beyond blocks Search confined within home mesh

 A new localized position based algorithm: 1. generate constant per node storage load. 2. Requires NO pre-knowledge of the network. 3. Guarantees nearby (closest) service selection with very high probability > 99% (resp., > 96%) at considerably low message cost.

Location service Flooding- based ProactiveReactive Quorum- based FlatHierarchical Home- based FlatHierarchical

 Actuator update: Each actuator selects a home region(a point/ geographic area ) that is known to others, and proactively sends location updates to nodes located in or closest to that region.  Actuator Search: sensors send search messages toward home region of the actuator, and the messages may possibly be redirected from there to current location of the actuator.

 The Two different approaches for routing.  The LS classification.  Each of the LS algorithms has its own advantages and dis advantages.  Need to more algorithms like iMesh.

 Stojmenovic, Ivan; Nayak, Amiya. Wireless Sensor and Actuator Networks : Algorithms and Protocols for Scalable Coordination and Data Communication.Hoboken, NJ, USA: Wiley, p 209.  Stojmenovic, Position based routing in ad hoc networks, IEEE Communications Magazine, Vol. 40, No. 7, July  Basagni, Stefano (Editor); Conti, Marco (Editor); Giordano, Silvia (Editor). Mobile Ad Hoc Networking. Hoboken, NJ, USA: Wiley,  Li X, Santoro N, Stojmenovic I. “Localized distance-sensitive service discovery in wireless sensor and actor networks”. IEEE Trans Comput 2009;58(9):1275– 1288  K.N. Amouris, S. Papavassiliou, and M. Li. “A position based multi-zone routing protocol for wide area mobile ad-hoc networks”. In Proceedings of the 49th IEEE Vehicular Technology Conference (VTC), pages 1365– 1369,  I. Stojmenovic, D. Liu, and X. Jia. “A scalable quorum based location  service in ad hoc and sensor networks”. International Journal  of Communication Networks and Distributed Systems, 1(1):71–94,  2008.

 Doubling Circle Update is a proactive flooding based algorithm where each actuator propagates its location information within circles C(i) of increasing radii 2 R for i = 1, 2, 3,..., What is the weakness of this algorithm?

 As a large update circle may contain all the network nodes, location update may possibly convert to flooding, leading to large amount of message overhead and limited scalability.

imesh is a Localized Distance-Sensitive Service Discovery protocol. Explain What does the Distance- sensitive imply and Why does it crucial in the Wireless Sensors Actuators Network?

 Distance-Sensitive means that each service consumer discovers the closest service provider or nearby (that is at most twice as far as the closest).  Distance-Sensitive is crucial as it is a primary concern for energy saving and timely response.

 In the iMesh algorithm, the blocking rule defines as following: A node receiving information from multiple service providers forwards only the information of the closest one, apply this rule on the following complete mesh where a,b,c,d,e,f,g nodes are service providers (actuators) and u,v,w nodes are service consumers (sensors)?

g e F