![Page 1: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/1.jpg)
COMMUNICATING VIA FIREFLIES: GEOGRAPHIC
ROUTING ON DUTY-CYCLED SENSORS
S. NATH, P. B. GIBBONS IPSN 2007
![Page 2: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/2.jpg)
Model• A sensor network.• Time is divided into discrete epochs.• At each epoch, each node decides to
sleep or wake up according to some decentralized sleep scheduling protocol.
• Only awake nodes can sense, process and communicate.
• A node can communicate only with its awake neighbors.
![Page 3: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/3.jpg)
Assumptions• Each node knows its geographic
location.• Nodes are loosely time synchronized.• The deployment of sensor nodes is
dense.
![Page 4: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/4.jpg)
Problem• Designing a sleep
scheduling algorithm for sensor nodes which ensures good routing performance.
• Analyzing the expected increase in routing latency as the number of awake nodes decreases.
![Page 5: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/5.jpg)
Motivation• Why Sleep Scheduling ?
– To reduce energy consumption.– And thus increase network lifetime.
• An inefficient sleep scheduling algorithm can result in disconnected networks and increase routing load 10 times.
![Page 6: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/6.jpg)
Related Work• Routing
– Greedy– For obstacles:
• Face • Hull
• Opportunistic Routing– For link failures.– For duty-cycled networks.
![Page 7: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/7.jpg)
Sleep Scheduling
Point/Spatial Coverage Node/Network Coverage
![Page 8: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/8.jpg)
Sleep Scheduling
Point/Spatial Coverage Node/Network Coverage
![Page 9: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/9.jpg)
Geographic Routing• All nodes awake.
![Page 10: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/10.jpg)
Geographic Routing• All nodes awake.
![Page 11: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/11.jpg)
Geographic Routing• All nodes awake.
![Page 12: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/12.jpg)
Geographic Routing• All nodes awake.
![Page 13: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/13.jpg)
Geographic Routing• When some nodes are sleeping
![Page 14: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/14.jpg)
Geographic Routing• When some nodes are sleeping
![Page 15: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/15.jpg)
Geographic Routing• When some nodes are sleeping
![Page 16: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/16.jpg)
Geographic Routing• When some nodes are sleeping
Forward message to best awake neighbor even if the message is going in wrong direction.
![Page 17: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/17.jpg)
Geographic Routing• When some nodes are sleeping
Forward message to best awake neighbor even if the message is going in wrong direction.
![Page 18: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/18.jpg)
Connected K-Neighborhood (CKN)
• The aim of the sleep scheduling algorithm is to ensure that:– Each node (sleeping or awake) has at least k
(given) awake neighbors at all epochs.– All the awake neighbors form a connected
network.– The number of awake nodes in each epoch
is minimized.– In each epoch, a different set of nodes are
awake.
![Page 19: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/19.jpg)
Connected K-Neighborhood (CKN)
• Formulated the problem as an optimization problem
• Proved that it is NP-complete.• Gave an approximate algorithm that is
within logarithmic factor of optimal.• The algorithm is distributed with low
communication, computation and memory costs.
![Page 20: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/20.jpg)
Algorithm
![Page 21: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/21.jpg)
Algorithm
These ranks are assigned so that neighbors can coordinate among themselves to decide which nodes will go to sleep.
![Page 22: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/22.jpg)
Algorithm
If the degree of node is <k , the node has to remain awake all the time.
![Page 23: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/23.jpg)
Algorithm
A node decides to sleep if its neighbors with lesser rank satisfy the two conditions.
![Page 24: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/24.jpg)
Example for k=2• 6 nodes , k=2
![Page 25: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/25.jpg)
Example for k=2• Ranks are generated by a random
generator.
1
23
45
6
![Page 26: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/26.jpg)
Example for k=2
1
23
45
6C = {1,5}
![Page 27: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/27.jpg)
Example for k=2
1
23
45
6C = {1,5}
C = {}
C = {1} C = {1,2}
C = {1,3}
C = {1,4}
![Page 28: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/28.jpg)
1
23
45
6C = {1,5}
C = {}
C = {1} C = {1,2}
C = {1,3}
C = {1,4}
Example for k=2
![Page 29: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/29.jpg)
1
23
45
6C = {1,5}
C = {}
C = {1} C = {1,2}
C = {1,3}
C = {1,4}
Example for k=2
![Page 30: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/30.jpg)
1
23
45
6C = {1,5}
C = {}
C = {1} C = {1,2}
C = {1,3}
C = {1,4}
• Nodes 3,4 and 5 cannot sleep because Condition 2 on C is not satisfied.
Example for k=2
![Page 31: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/31.jpg)
Another Example for k=2• Same graph, but with
different ranks.
6
24
35
1
![Page 32: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/32.jpg)
Another Example for k=2
6
24
35
1C = {}
C = {1,2,3,4,5}
C = {} C = {2,3}
C = {}
C = {1,3}
![Page 33: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/33.jpg)
Another Example for k=2
6
24
35
1C = {}
C = {1,2,3,4,5}
C = {} C = {2,3}
C = {}
C = {1,3}
![Page 34: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/34.jpg)
Another Example for k=2
6
24
35
1C = {}
C = {1,2,3,4,5}
C = {} C = {2,3}
C = {}
C = {1,3}
![Page 35: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/35.jpg)
Another Example for k=2
6
24
35
1C = {}
C = {1,2,3,4,5}
C = {} C = {2,3}
C = {}
C = {1,3}
Nodes 4 and 5 cannot sleep because Condition 1 on C is not satisfied.
![Page 36: COMMUNICATING VIA FIREFLIES: GEOGRAPHIC ROUTING ON DUTY-CYCLED SENSORS S. NATH, P. B. GIBBONS IPSN 2007](https://reader036.vdocument.in/reader036/viewer/2022062600/5a4d1bc87f8b9ab0599d5ac7/html5/thumbnails/36.jpg)
Theoretical Analysis• Only the greedy forwarding part is
analyzed.• A lower bound on OPT and upper bound
on CKN is used to prove that :– |CKN| <= O(ln n) |OPT|
• They show that the probability of greedy forwarding making negative progress decreases exponentially with the increase in number of neighbors.