Sink Mobility in
Wireless Sensor Networks
CSI 5148
Andres Solis Montero
Data Gathering
Introduction
Overview
Sink Mobility
Problem
References
Introduction
Solutions
Questions
• Is a fundamental task in Wireless Sensor Networks (WSNs),
here its function is to send sensor
readings from sources to sinks nodes.
Sink Mobility in Wireless Sensor Networks
Andres Solis Montero
1/23
Energy Consumption
Introduction
Overview
Sink Mobility
Problem
References
Problem
Solutions
Questions
• Sensors near the sink deplete their battery power
faster than those far apart due to the heavy traffic of
relaying messages.
- When a sink’s neighbours deplete
their battery power, farther away
nodes may still have more than
90% of their initial energy -
Ingelrest et al., (2004)
Luo and Hubaux, (2005)
Olariu and Stojmenovic, (2006)
Vincze et al., (2007)
Sink Mobility in Wireless Sensor Networks
Andres Solis Montero
2/23
Energy Consumption
Introduction
Overview
Sink Mobility
Problem
References
Problem
Solutions
Questions
• Sink isolation, network failure.
• Energy holes, degraded
network performance.
• Manually replace/recharge
sensor batteries is often
infeasible.
It is desired to minimize and balance energy usage among sensors.
Sink Mobility in Wireless Sensor Networks
Andres Solis Montero
3/23
Power-aware Routing
Introduction
Overview
Sink Mobility
Problem
References
Solutions ?
Questions
Solutions
Power Aware
Non Uniform
Sink Mobility
•Longer network life time.
•Balances energy consumption.
Singh et al., (1998)
Stojmenovic and Lin, (2001)
Buragohain et al., (2005)
Sink Mobility in Wireless Sensor Networks
Limitation:
Critical nodes are not
avoidable.
Andres Solis Montero
4/23
No uniform node distribution
Introduction
Overview
Sink Mobility
Problem
References
Solutions ?
Questions
Solutions
Power Aware
Non Uniform
Sink Mobility
•Mitigates message relay load.
•Increases network lifetime.
Stojmenovic et al., (2005)
Lian et al., (2006)
Wu et al., (2008).
Sink Mobility in Wireless Sensor Networks
Limitation:
Reduces coverage which
is the basis of any sensor
network.
Andres Solis Montero
5/23
Sink Mobility
Introduction
Overview
Sink Mobility
Problem
References
Solutions ?
Questions
Solutions
Power Aware
Non Uniform
Sink Mobility
•Improves network lifetime,
without bringing negative
impacts mentioned in the other
approaches.
•Network coverage preserved.
•There are no ‘critical’ nodes
around a sink due to its
mobility.
Akkaya et al., (2005);
Luo and Hubaux, (2005);
Vincze et al., (2007);
Banerjee et al., (2008);
Basagni et al., (2008);
Hashish and Karmouch, (2008);
Friedmann and Boukhatem, (2009)
Sink Mobility in Wireless Sensor Networks
Andres Solis Montero
6/23
Sink Mobility
Introduction
Taxonomy
Sink Mobility
Delay Tolerant WSN
References
Taxonomy
Questions
Data Gathering in
delay-tolerant WSN
•
•
Habitat monitoring.
Water quality Monitoring.
Sink Mobility in Wireless Sensor Networks
Real Time WSN
Data Gathering in
real-time WSN
•
•
Battlefield surveillance.
Forest fire detection.
Andres Solis Montero
7/23
Delay Tolerant WSN approaches
Taxonomy
Taxonomy
Sink Mobility
Delay Tolerant WSN
Direct Contact
References
Rendezvous based
Real Time WSN
Questions
Direct Contact
Data Collection
Stochastic
Introduction
TSP
Rendezvous based
Data Collection
Label Covering
Sink Tours
Sinks visit (possibly at slow speed)
all data sources and obtain data directly from
them.
Fixed Track
Tree-Based
RP Selection Methods
Sinks may visit only a few selected
rendezvous points (RPs).
Kansal et al. (2004)
Xing et al. (2008), (2007)
Shah et al. (2003); Gu et al. (2005);
Nesamony et al. (2007); Sugihara and Gupta. (2008).
Sink Mobility in Wireless Sensor Networks
Clustering
Andres Solis Montero
8/23
Delay Tolerant WSN approaches
Direct Contact data Collection
TSP
Taxonomy
Sink Mobility
Delay Tolerant WSN
Direct Contact
References
Rendezvous based
Real Time WSN
Questions
•Eliminates the message relay
overhead of sensors, and thus
optimizes their energy savings.
Direct Contact
Data Collection
Stochastic
Introduction
Limitation:
•It has a large data collection
latency for slow moving sinks.
Label Covering
Sink Tours
Sinks visit (possibly at slow speed)
all data sources and obtain data directly from
them.
Shah et al. (2003); Gu et al. (2005);
Nesamony et al. (2007); Sugihara and Gupta. (2008).
Sink Mobility in Wireless Sensor Networks
Concern:
•Find best sink trajectory that
covers all sensors minimizing
data collection delay.
Andres Solis Montero
9/23
Stochastic
Direct Contact data collection
Introduction
Taxonomy
Sink Mobility
Delay Tolerant WSN
Direct Contact
References
Rendezvous based
Real Time WSN
Questions
•Each sensor buffers their measurements and
waits for a sink (beacon).
•Sinks move randomly sending beacons and
collect data from encountered sensors in
communication range.
•Data is carried by the sink to access point.
Shah et al. (2003);
Limitations:
•It has a large data collection latency for
slow moving sinks.
•Constant channel monitoring (beacons)
is energy expensive.
If a sink moves along a regular path, sensors can
predict their arrival after learning their pattern. Chakrabarti et al. (2003);
Sink Mobility in Wireless Sensor Networks
Andres Solis Montero
10/23
TSP Tour for data collection
Direct Contact data collection
Introduction
Taxonomy
Sink Mobility
Delay Tolerant WSN
Direct Contact
References
Rendezvous based
Real Time WSN
Questions
•Equivalent NP- complete Travel Salesman Problem.
•Traveling Salesman with Neighbourhood (TSPN)
All locations are known.
First determine visiting order of the disks.
TSP order of the disks. Constrains may apply
(energy level, buffer overflow...).
For each disk, a representative points is selected.
(center, closest point to starting point, random...)
Algorithm computes the optimum path according
the order. B = min(|AB|+|BC|) adjacent edges.
Limitations:
•It has a large data collection latency for
slow moving sinks.
•TSP – NP complete problem.
Sink Mobility in Wireless Sensor Networks
Nesamony et al. (2006, 2007);
Andres Solis Montero
11/23
Label-covering tour data collection
Direct Contact data collection
Introduction
Taxonomy
Sink Mobility
Delay Tolerant WSN
Direct Contact
References
Rendezvous based
Real Time WSN
Questions
•All locations are known. No need to visit all nodes once.
•Complete graph is made with sensors and
initial positions.
•Edges have a cost (Euclidean distance) and
labels of all nodes (transmission radius) they
intersect.
•Minimum set of edges that can collect data from
all nodes.
Sugihara and Gupta (2007, 2008)
Proved to have better performance than TSP solutions
with large transmission radius.
Limitations:
•It has a large data collection latency for slow moving sinks.
•Minimum label problem is NP hard.
•No restrictions are applied to the algorithm (energy level, buffer overflow...).
Sink Mobility in Wireless Sensor Networks
Andres Solis Montero
12/23
Delay Tolerant WSN approaches
Rendezvous based data Collection
Sink Mobility in Wireless Sensor Networks
Sink Mobility
Delay Tolerant WSN
Direct Contact
References
Rendezvous based
Real Time WSN
Rendezvous based
Data Collection
•Reduces time and data
collection latency.
Concern:
•Trade-off of energy
consumption and time delay.
Taxonomy
Questions
•Avoids long travel distances.
Limitation:
•More energy consumption
because of multi hop data
communication.
Introduction
Fixed Track
Tree-Based
Clustering
RP Selection Methods
Sinks may visit only a few selected
rendezvous points (RPs).
Kansal et al. (2004)
Xing et al. (2008), (2007)
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RP selection by fixed Track.
Rendezvous based data Collection
Introduction
Taxonomy
Sink Mobility
Delay Tolerant WSN
Direct Contact
References
Rendezvous based
Real Time WSN
Questions
•Sink moves through straight lines (fixed track)
broadcasting beacon messages initially.
•Sensors build a MST using hop counts.
Their resend the min count received.
•The roots are the RPs.
• Sink motion can be slow or temporarily stop
in critical data delivery places.
• Each sensor belongs to only one tree.
Limitation:
•More energy consumption because of multihop
data communication.
•Find better fixed track and MST configuration to balance time
and message load.
Sink Mobility in Wireless Sensor Networks
Andres Solis Montero
Kansal et al. (2004)
Xing et al. (2008), (2007)
14/23
RP selection by Reporting Tree
Rendezvous based data Collection
Introduction
Taxonomy
Sink Mobility
Delay Tolerant WSN
Direct Contact
References
Rendezvous based
Real Time WSN
Questions
Greedy algorithm with constrained Reporting Tree path
rooted at BS.
•Need to find a sub-path where the maximum
distance traveled by the sink is L.
(max L that can travel within D Time).
•Each edge has a weight based on their children.
• Edges are sorted according to their weight.
The biggest values <= L are selected.
• RPs are at any point of the final path.
Limitation:
•More energy consumption because of multi hop data
communication.
•Configuration L input might yield different results.
Sink Mobility in Wireless Sensor Networks
Andres Solis Montero
Xing et al. (2008), (2007)
15/23
RP selection by Clustering
Rendezvous based data Collection
Introduction
Taxonomy
Sink Mobility
Delay Tolerant WSN
Direct Contact
References
Rendezvous based
Real Time WSN
Questions
•Framework integrating several algorithms.
•K-hop clusters are constructed.
•Each cluster is a minimum hop tree rooted at its
Navigation Agent (NA) with a depth of at least
K+1 and at most 2k+1.
•A TSP tour of NA is used for the sink. They use
min hop links between clusters.
•Info is collected 1-hop of the NA (data replication,...)
Limitation:
•More energy consumption because of multi hop data
communication.
•Configuration k input might yield different results.
•k=1 direct contact data collection.
•k=kmax (n : network size) static sink scenario.
Sink Mobility in Wireless Sensor Networks
Andres Solis Montero
Rao and Biswas (2008)
16/23
Real Time WSN approaches
Taxonomy
Sink Relocation
strategies
Cluster based
Brute Force
Event-Driven
Introduction
Taxonomy
Sink Mobility
Delay Tolerant WSN
Real Time WSN
References
Sink Relocation
Questions
Data Dissemination
Data Dissemination
To mobile sinks
MILP
Tree based
Learning-based
Request zone
Periphery Tree-based
Multi hop message relay with optimal sink relocation
and routing algorithms for data dissemination to mobile sinks.
Banerjee et al. (2008), Bi et al. (2007),
Vincze et al. (2007), Bogdanov et al.,
2004.
Sink Mobility in Wireless Sensor Networks
Wu and Chen (2007), Kim et al. (2003)
Baruah et al. (2004) , Ammari and Das
(2005)
Andres Solis Montero
17/23
Real Time WSN approaches
Taxonomy
Introduction
Taxonomy
Sink Mobility
Delay Tolerant WSN
Real Time WSN
References
Sink Relocation
Questions
Data Dissemination
Concern:
•Reduce multi hop message relay with
optimal sink relocation.
Sink Relocation
strategies
•Sinks move through energy-intense
areas rather than energy-sparse areas.
Cluster based
Brute Force
Event-Driven
MILP
Periphery Tree-based
Limitation:
•More energy consumption because of
multi hop data communication.
Banerjee et al. (2008), Bi et al. (2007),
Vincze et al. (2007), Bogdanov et al.,
2004.
Sink Mobility in Wireless Sensor Networks
•Optimal multi sink placement is
NP-Complete problem.
Andres Solis Montero
18/23
Brute Force approach
Sink Relocation
Introduction
Taxonomy
Sink Mobility
Delay Tolerant WSN
Real Time WSN
References
Sink Relocation
Questions
Data Dissemination
•Sinks have a global view of the network and
run a centralized algorithm.
•Algorithm runs periodically to check if sinks
should be relocated.
•Sink relocation takes place if and only if the
new sink position reduces total cost.
•Each edge is assigned a weight based on
the remaining energy and cost of the
message transmitting.
Friedmann and Boukhatem (2009)
Sink Mobility in Wireless Sensor Networks
Limitation:
•More energy consumption because of
multi-hop data communication.
• Optimal positions NP-Complete.
Andres Solis Montero
19/23
Data Dissemination to mobile sinks
Taxonomy
•It is the problem of data routing to sinks in
the presence of sink mobility.
Introduction
Taxonomy
Sink Mobility
Delay Tolerant WSN
Real Time WSN
References
Sink Relocation
Questions
Data Dissemination
Data Dissemination
To mobile sinks
•Data dissemination with mobile sinks is a
combined problem of LOCATION and
ROUTING.
Tree based
Learning-based
Concern:
•Fast and correct delivery with trade-off energy consumption.
Request zone
Wu and Chen (2007), Kim et al. (2003)
Baruah et al. (2004) , Ammari and Das
(2005)
Limitation:
•More energy consumption because of
multi-hop data communication and sink reposition.
Sink Mobility in Wireless Sensor Networks
Andres Solis Montero
20/23
Request Zone
Data Dissemination
Introduction
Taxonomy
Sink Mobility
Delay Tolerant WSN
Real Time WSN
References
Sink Relocation
Questions
Data Dissemination
•Sink will move from a1 to a2.
•Sink advertises by flooding with
positions a1 and a2 before it
starts moving.
•Each sensor computes the circle with diameter
d1 and d2. Then it computes the sensors in its
transmission area towards c; center of the circle with D=|a1,a2|.
•Directional routing is used from the sensor to the center of the
circle.
Limitation:
•More energy consumption because of
multi hop data communication and sink reposition.
•Needs complete coverage of nodes, routing to c is not the
expected sink position and directional routing could be a
problem.
Sink Mobility in Wireless Sensor Networks
Andres Solis Montero
Ammari and Das (2005)
21/23
Introduction
References
Sink Mobility
References
Thanks for Listening...
Questions
1.
Ivan Stojmenovic, Amiya Nayak. “Wireless Sensor and Actuator Networks:
Algorithms and Protocols for Scalable Coordination and Data Communication”
Wiley-Intercience, Chapter 6, pp. 153- 181. 2009.
2.
Shah RC, Roy S, Jain S, Brunette W. “Data MULEs: modeling
and analysis of a three-tier architecture for sparse sensor
networks”. Ad Hoc Netw 2003;1(2–3):215–233.
Chakrabarti A, Sabharwal A, Aazhang B. “Using predictable
observer mobility for power efficient design of sensor
networks”. Proceedings of the 2nd InternationalWorkshop on
Information Processing in Sensor Networks (IPSN), Volume
2634 of LNCS; 2003. pp. 129–145.
Nesamony S, Vairamuthu MK, Orlowska ME, Sadiq SW. “On
optimal route computation of mobile sink in a wireless sensor
network”. Technical Report 465. ITEE, University of
Queensland; 2006.
Sugihara R, Gupta RK. “Improving the data delivery latency in
sensor networks with controlled mobility”. Proceedings of the
4th IEEE International Conference on Distributed Computing
inSensor Systems (DCOSS), Volume 5067 of LNCS; 2008. pp.
386–399.
Kansal A, Somasundara AA, Jea DD, Srivastava MB, Estrin D.
“Intelligent fluid infrastructure for embedded networks”.
Proceedings of the 2nd International Conference on Mobile
Systems, Applications, and Services (MobiSys); 2004. pp. 111–
124.
3.
4.
5.
6.
Sink Mobility in Wireless Sensor Networks
7.
Xing G, Wang T, Jia W, Li M. “Rendezvous design algorithms for
wireless sensor networks with a mobile base station”.
Proceedings of the 9th ACM International Symposium on
Mobile Ad Hoc Networking and Computing (MobiHoc); 2008.
pp. 231–239.
8. Xing G, Wang T, Xie Z, Jia W. “Rendezvous planning in mobilityassisted wireless sensor networks”. Proceedings of the 28th
IEEE International Real-Time Systems Symposium (RTSS);
2007.pp. 311–320.
9. Rao J, Biswas S. “Joint routing and navigation protocols for
data harvesting in sensor networks”. Proceedings of the 5th
IEEE International Conference on Mobile Ad-hoc and Sensor
Systems (MASS); 2008. pp. 143–152.
10. Friedmann L, Boukhatem L. “Efficient multi-sink relocation in
wireless sensor network”. Ad Hoc & Sens Wirel Netw 2009. To
appear.
11. Ammari HM, Das SK. “Data dissemination to mobile sinks in
wireless sensor networks: an information theoretic approach”.
Proceedings of the 2nd IEEE International Conference on
Mobile Adhoc and Sensor Systems (MASS); 2005. pp. 314–321.
Andres Solis Montero
22/23
Question 1
Introduction
Question 1
Sink Mobility
Question 2
References
Delay Tolerant WSN >> Direct Data Collection >> TSP tour .
Question 3
Questions
1. In Delay Tolerant WSNs, direct data collection approaches try to minimize the
trip made by the sink visiting all sensors in the network. Knowing a min TSP tour
of ‘1,2,3,4’ ; construct a minimal path using the TSPN (Travel Salesman Problem
with Neighbourhood) algorithm.
Sink Mobility in Wireless Sensor Networks
Andres Solis Montero
Question 1
Introduction
Question 1
Sink Mobility
Question 2
References
Delay Tolerant WSN >> Direct Data Collection >> TSP tour .
Sink Mobility in Wireless Sensor Networks
Questions
Andres Solis Montero
Question 3
Question 1
Introduction
Question 1
Sink Mobility
Question 2
References
Delay Tolerant WSN >> Direct Data Collection >> TSP tour .
Sink Mobility in Wireless Sensor Networks
Questions
Andres Solis Montero
Question 3
Question 1
Introduction
Question 1
Sink Mobility
Question 2
References
Delay Tolerant WSN >> Direct Data Collection >> TSP tour .
Sink Mobility in Wireless Sensor Networks
Question 3
Questions
Andres Solis Montero
1/Y
Question 1
Introduction
Question 1
Sink Mobility
Question 2
References
Delay Tolerant WSN >> Direct Data Collection >> TSP tour .
Sink Mobility in Wireless Sensor Networks
Question 3
Questions
Andres Solis Montero
1/Y
Question 1
Introduction
Question 1
Sink Mobility
Question 2
References
Delay Tolerant WSN >> Direct Data Collection >> TSP tour .
Sink Mobility in Wireless Sensor Networks
Questions
Andres Solis Montero
Question 3
Question 1
Introduction
Question 1
Sink Mobility
Question 2
References
Delay Tolerant WSN >> Direct Data Collection >> TSP tour .
Sink Mobility in Wireless Sensor Networks
Questions
Andres Solis Montero
Question 3
Question 1
Introduction
Question 1
Sink Mobility
Question 2
References
Delay Tolerant WSN >> Direct Data Collection >> TSP tour .
Sink Mobility in Wireless Sensor Networks
Questions
Andres Solis Montero
Question 3
Question 1
Introduction
Question 1
Sink Mobility
Question 2
References
Delay Tolerant WSN >> Direct Data Collection >> TSP tour .
Sink Mobility in Wireless Sensor Networks
Questions
Andres Solis Montero
Question 3
Question 1
Introduction
Question 1
Sink Mobility
Question 2
References
Delay Tolerant WSN >> Direct Data Collection >> TSP tour .
Sink Mobility in Wireless Sensor Networks
Questions
Andres Solis Montero
Question 3
Question 2
Introduction
Question 1
Sink Mobility
Question 2
References
Delay Tolerant WSN >>Direct Data Collection >> Label-covering tour.
Question 3
Questions
2. Having the same sensors and sink configuration but this time without a
minimal TSP tour; would it be possible to give the shortest path using a Labelcovering tour approach? If yes, give the shortest path using such an algorithm.
Sink Mobility in Wireless Sensor Networks
Andres Solis Montero
Question 2
Introduction
Question 1
Sink Mobility
Question 2
References
Delay Tolerant WSN >>Direct Data Collection >> Label-covering tour.
Sink Mobility in Wireless Sensor Networks
Questions
Andres Solis Montero
Question 3
Question 2
Introduction
Question 1
Sink Mobility
Question 2
References
Delay Tolerant WSN >>Direct Data Collection >> Label-covering tour.
Sink Mobility in Wireless Sensor Networks
Questions
Andres Solis Montero
Question 3
Question 2
Introduction
Question 1
Sink Mobility
Question 2
References
Delay Tolerant WSN >>Direct Data Collection >> Label-covering tour.
Sink Mobility in Wireless Sensor Networks
Questions
Andres Solis Montero
Question 3
Question 3
Introduction
Question 1
Sink Mobility
Question 2
References
Real Time WSN >> Data Dissemination >> Request Zone
Question 3
Questions
3. Data dissemination to mobile sinks deals with the problem of correctly routing
data to sinks. In the Request Zone algorithm, the sink, before it starts moving,
will flood its starting and ending position. Eventually, all nodes will have that
information and they will route messages to point c. (center of the circle formed
by the diameter determined by |s,e|). The routing solution given by this
algorithm will fail in the following scenario starting from the gray node. Why? Is
it possible to correct the data delivery starting from the gray sensor using the
routing algorithm studied in class?
Sink Mobility in Wireless Sensor Networks
Andres Solis Montero
Question 3
Introduction
Question 1
Sink Mobility
Question 2
References
Real Time WSN >> Data Dissemination >> Request Zone
Sink Mobility in Wireless Sensor Networks
Questions
Andres Solis Montero
Question 3
Question 3
Introduction
Question 1
Sink Mobility
Question 2
References
Real Time WSN >> Data Dissemination >> Request Zone
Sink Mobility in Wireless Sensor Networks
Questions
Andres Solis Montero
Question 3
Sink Mobility in
Wireless Sensor Networks
THANKS !! GRACIAS!!
Andres Solis Montero