G EOGRAPHIC R OUTING P ROTOCOLS IN W IRELESS S ENSOR N ETWORKS F OCUS ON R EAL T IME R OUTING AND P ROTOCOLS S UPPORTING M OBILITY Imane BENKHELIFA Research Associate, CERIST, Algeria 1 st year PhD Student, USTHB, Algeria

O UTLINE Routing Protocols Cliassification of Routing Protocols Geographic Protocols QoS Routing Protocols MultiPath Protocols Routing Protocols supporting Mobility Routing Protocols with Localization Errors 2

R OUTING P ROTOCOL Design Constraints for routing in WSN: Autonomy : nodes make decisions Energy Efficiency: Prolonging network life time while maintaining a good grade of connectivity Scalability: works with a large amount of nodes Resilience: if some nodes stop operating, an alternative route should be discovered Device heterogeneity: the use of nodes with different processors, transceivers, power units or sensing components Mobility Adaptability: supports the mobility of nodes (sinks, events…) 3

R OUTING P ROTOCOL Additional constraints for certain applications such as “ Emergency Response ”: Stateless Architecture: it does not require routing table  minimum memory Soft Real-time: minimum delay QoS Routing and Congestion Management : avoids congestion, re-routes packets, minimum control overhead Traffic Load Balance: multi path, concurrent routes Localized behavior: only delay changes will be sent to neighbors 4

O UTLINE Routing Protocols Cliassification of Routing Protocols Geographic Protocols QoS Routing Protocols MultiPath Protocols Routing Protocols supporting Mobility Routing Protocols with Localization Errors 5

C LASSIFICATION RoutingNetwork StructureFlatDD,SPIN,RR,MCFAHierarchicTEEN,LEACH,TTDDGeographicSPEED,GOAFR,GEER Protocol operations NegociationSPINQueryDD,RumorQoSSAR,SPEED,MMSPEEDMulti-PathBraided, N to 1CoherenceRumor 6

O UTLINE Routing Protocols Cliassification of Routing Protocols Geographic Protocols QoS Routing Protocols MultiPath Protocols Routing Protocols supporting Mobility Routing Protocols with Localization Errors 7

G EOGRAPHIC R OUTING IN WSN 8 Motivations of Using Geographic Routing Approach in WSNs Simplicity: simple calculations Stateless: memory conservation Autonomy : nodes make decisions Energy Efficiency: prolonging network life time while maintaining a good grade of connectivity Scalability: works with a large amount of nodes

G EOGRAPHIC R OUTING IN WSN Forwarding techniques in geographic routing are: Compass routing(C), GRS(G), MFR(M) and NFP(N) 9

G EOGRAPHIC R OUTING IN WSN Greedy Algorithms: choosing among neighbors the nearest to the sink (the Euclidian distance is a metric of choosing), the process repeats until the packet reaches the final destination, 10

G EOGRAPHIC R OUTING IN WSN Drawback: if the current holder has no neighbors closer to the destination than itself !!!!! 11

G EOGRAPHIC R OUTING IN WSN GAF (Geographic Adaptive Fidelity): Forms a virtual grid of the covered area Three node states: Discovery, Active and Sleep Each node associates itself with a cell in the grid based on its location Nodes associated with the same cell are equivalent Some nodes in an area are kept sleeping to conserve energy Nodes change state from sleeping to active for load balancing 12

G EOGRAPHIC R OUTING IN WSN GAF Advantages: Increase the lifetime of the network significantly Considered to be hierarchical protocol Each sub-region is a cluster Representative node is a cluster head GAF Disadvantages: Does not perform any data aggregation Not very scalable Overhead of forming the grid Only the active nodes sense and report data  data accuracy is not very high 13

O UTLINE Routing Protocols Cliassification of Routing Protocols Geographic Protocols QoS Routing Protocols MultiPath Protocols Routing Protocols supporting Mobility Routing Protocols with Localization Errors 14

Q O S R OUTING P ROTOCOLS IN WSN 15 Motivations of Using QoS Routing Approach in WSNs Ensure Quality of Service in terms of : Delay Bandwith Energy Load Balancing

Q O S R OUTING P ROTOCOLS IN WSN SPEED: Aims to reduce the End-to-End deadline miss ratio Supposes that E2E Deadlines are proportional to the distance between the source and the destination using feed-back control Guarantees deadline by maintaining a packet delivery speed across the network. Velocity = Distance (s,d) / required deadline 16

Q O S R OUTING P ROTOCOLS IN WSN SPEED: The forwarding nodes are calculated from the neighbor nodes having to be at least k distance closer to the destination If no speed matches, a neighborhood feed-back determines whether to drop the packet or to re-route it 17 S FD R K

O UTLINE Routing Protocols Cliassification of Routing Protocols Geographic Protocols QoS Routing Protocols MultiPath Protocols Routing Protocols supporting Mobility Routing Protocols with Localization Errors 18

M ULTI P ATH G EOGRAPHIC R OUTING IN WSN Motivations of Using Multipath Routing Approach in WSNs Reliability and Fault-Tolerance Load Balancing and Bandwidth Aggregation QoS Improvement 19

M ULTI P ATH G EOGRAPHIC R OUTING IN WSN MMSPEED (Multi path Multi SPEED): Introduces multiple speed levels (layers) to guarantee timeliness packet delivery Each packet is assigned to a speed layer and then placed in a queue High priority before low priority Source determines for each packet the speed regarding the destination and its specific E2E deadline If an intermediate node perceives that this packet cannot meet its specific deadline, the intermediate selects another speed layer Reliability is guaranteed by controlling active paths and sending multiple copies 20

M ULTI P ATH G EOGRAPHIC R OUTING IN WSN MMSPEED (Multi path Multi SPEED): 21 A B C D = distance A-C – distance B-C distance A-B distance B-C destination Geographic progress that can be made towards the destination by selecting node B as the next forwarder

M ULTI P ATH G EOGRAPHIC R OUTING IN WSN Challenges: The main disadvantage lies in the cost of maintaining the paths. This cost comprises in memory resources and network overhead  so not suitable for networks critically by their reduced batteries. However, they become necessary when reliability is a strong requirement 22

O UTLINE Routing Protocols Cliassification of Routing Protocols Geographic Protocols QoS Routing Protocols MultiPath Protocols Routing Protocols supporting Mobility Routing Protocols with Localization Errors 23

R OUTING P ROTOCOLS SUPPORTING M OBILITY IN WSN Motivations of Using Routing Approach in WSNs with mobile sinks Mobile sinks prolong the networks lifetime Load Balancing and Bandwidth Aggregation QoS Improvement 24

R OUTING P ROTOCOLS SUPPORTING M OBILITY IN WSN TTDD (Two Tier Data Dissemination): Static sensors vs Mobile sinks Each active source creates a grid over the static network with grid points acting as dissemination nodes. A mobile sink sends out a locally controlled flood that discovers its nearest dissemination point. 25   D S

R OUTING P ROTOCOLS SUPPORTING M OBILITY IN WSN ALURP (Adaptive Local Update-based Routing Protocol): The adaptive area is constructed as the circle (VC, D vc,sink ). 26 DN VC Area B Area A DN A DN B

R OUTING P ROTOCOLS SUPPORTING M OBILITY IN WSN Problem: When the sink moves toward the VC, the DN still keep the previous location of the sink and therefore will send the packet to a wrong place, because sink informs only the new area about its new location. 27 Solution: Inform the former adaptive area but not the current adaptive area to flush the topology information of the sink.

R OUTING P ROTOCOLS SUPPORTING M OBILITY IN WSN ALURP Advantages: Saves energy and keeps communication with sensors and sink thanks to the adaptive area. The destination area can be expressed by its radius R. 28

R OUTING P ROTOCOLS SUPPORTING M OBILITY IN WSN ALURP Drawbacks: How to inform only the former adaptive area but not the current adaptive area ????? DN may excessively consume energy, because source always sends data to the DN instead of the sink, which can be a bottleneck !!!!!! If the destination area is too small and sink changes frequently its position  too much of energy consumption by sensors to update routes !!!!! 29

R OUTING P ROTOCOLS SUPPORTING M OBILITY IN WSN Energy-Efficient Routing in MWSN using Mobility Prediction : Mobile sink estimates and tracks its state (location, velocity, acceleration) from noisy measurements with a kalman filter. The source predicts the location of the mobile sink The state of the predictor is updated by receiving STATE- UPDATE from the mobile sink. The STATE-UPDATE is only sent when the Euclidean norm of the error between the predicted state and the estimated state by Kalman Filter exceeds a pre-defined threshold. 30

R OUTING P ROTOCOLS SUPPORTING M OBILITY IN WSN The STATE-UPDATE and DATA messages are forwarded in a multi hop fashion Uses greedy forwarding. 31

ELASTIC : A -A node uses greedy forwarding -The mobile sink broadcasts its new position every 1 m -Each node listens to the transmission of his successor and detects the change of the sink position and changes it for its next transmission - The process repeats until the source node B R OUTING P ROTOCOLS SUPPORTING M OBILITY IN WSN 32

O UTLINE Routing Protocols Cliassification of Routing Protocols Geographic Protocols QoS Routing Protocols MultiPath Protocols Routing Protocols supporting Mobility Routing Protocols with Localization Errors 33

R OUTING P ROTOCOLS WITH L OCALIZATION E RRORS Motivations of Using Routing protocols with Localization Errors Nodes’ positions are not always accurate If the packet contains a wrong position, the packet will not reach its destination QoS Improvement by introducing localization errors in routing decisions 34

R OUTING P ROTOCOLS WITH L OCALIZATION E RRORS ELLIPSE The region is defined by an ellipse  source position, sink position, distance between them, an ellipse factor “ l ”. All nodes in the ellipse region and those who receive msg, forward it with a probability “ p ”. Neighbors of source and sink always forward msg even if they are out of the ellipse. 35

R OUTING P ROTOCOLS WITH L OCALIZATION E RRORS ELLIPSE Assumptions: probability “ p ” defines a sub-set of nodes which will relay msg towards destination before deployment, all the sensors know the ellipse factor and destination position before sending, the source includes its position (x s, y s ) when sensor “ u ” receives a msg, it checks whether it is inside the ellipse by the following formula: D su + D ud <= l.d where l : ellipse factor, d: distance between source and sink 36

R OUTING P ROTOCOLS WITH L OCALIZATION E RRORS Localization error management in ELLIPSE: When the source is not accurately located, because it’s an important parameter to define the ellipse: all neighbors of the source have to forward msg (to relay nodes) even if they are outside the ellipse. 37

R OUTING P ROTOCOLS WITH L OCALIZATION E RRORS Localization error management in ELLIPSE: Problem: to how many hops?? If h=1  all 1-hop neighbors are relay nodes  Solution: the minimal number of hops to reach sensors close to S is the ceiling of [/r]. To avoid dropping msg: h>= [/r] +1 Problem: when the node’s position is not accurate, because it cannot determine if it is inside the ellipse  it cannot determine if it is a relay node.  Solution: each potential relay node can calculate its probability to be inside the ellipse P A = A A / ² A ….where A A is the intersection of the circle of A and the ellipse 38

R OUTING P ROTOCOLS WITH L OCALIZATION E RRORS Summary: Managing Localization error leads to significant energy consumption Suitable to mobile network because there’s no need to know neighbors position Drawbacks: Does not focus on the broadcasting strategy inside the ellipse !!! Why choosing Ellipse as a region and not other region form??? 39

S UMMARY ProtocolCategory Greedy ForwardingGeographic GAFGeographic SPEEDQoS-based MMSPEEDMultiPath-based & QoS-based TTDD, ALURP, EERMP, ELASTICGeographic supporting Mobility ELLIPSEGeographic with localization error 40

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