Energy-Efficient Shortest Path Self-Stabilizing Multicast Protocol for Mobile Ad Hoc Networks Ganesh...
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Transcript of Energy-Efficient Shortest Path Self-Stabilizing Multicast Protocol for Mobile Ad Hoc Networks Ganesh...
Energy-Efficient Shortest Path Self-Stabilizing Multicast
Protocol for Mobile Ad Hoc Networks
Ganesh [email protected]
Outline
Introduction Goals System Model Cost metric Simulation & Implementation Conclusion
Introduction
Mobile Ad Hoc Networks (MANETs) No infrastructure Limited transmission range Energy constrained
Multicasting in MANETs Why multicast as opposed to multiple
unicast? Less number of messages Less energy spent
Introduction
Issues in MANET Multicasting Dynamic Topology Energy constrained Possible solution – flooding
Suffers from redundant rebroadcast Increase in collision and contention Energy inefficient
Tree or Mesh Structure Examples: MAODV, ODMRP etc.
Shortest Path Self-Stabilizing ProtocolSS-SPST
Shortest path spanning tree from root Pro active tree construction Tree includes both multicast group and non-group nodes
Faults Change in topology caused by mobility
SS-SPST is self-stabilizing Converge to a global legitimate state from an illegitimate
state Fault-tolerant solution
SS-SPST is distributed Uses only local knowledge
Self-Stabilization Properties
Convergence Closure
Inter-communication Share memory Message passing
Beaconing Time complexity
Rounds Round definition in a lossy medium
A round is defined to be the time period in which each node in the system receives at least one beacon message from each of its neighbors and performs computation based on the information it has received.
SS-SPST Cost metric
Multicast tree is constructed to optimize the cost metric
Currently hop count is the cost metric
Goal: To optimize energy An energy-efficient cost metric is required
to minimize total energy consumption
Wireless Multicast Advantage
X
Y
Z
PXZ
PXY
PXZ > PXY
Motivation - example
R
1 2
NG
NG
NG
X
Total discard energy = 3 * Reception energy
Problem Statement
Propose energy-efficient cost metric Simulation based performance
comparison with MAODV and ODMRP Comparison of different cost metrics
MAODV & ODMRP
MAODV properties Tree based On-demand Route request and route reply phase
ODMRP properties Mesh based On-demand Many routes to the receivers
System Model - Assumptions
Unique identification Periodic beaconing Soft-state neighbors Cost metric computation Dynamic transmission range Active mode Single source multicasting
Energy Model
ETx = Eelec . K + Eamp . K . d2
ERx = Eelec . K
Eelec = Fixed energy
Eamp = Amplification energy
K = Number of bits d = distance
SS-SPST - Algorithm If (root)
Dist-to-root = 0Parent = -1
elseDist-to-root = Shortest
distance to root through any
neighbor node ‘i’
Parent = i
R
1 2
NG
NG
NG
X
SS-SPST An Example
SS-SPST An Example
R
1 2
NG
XNG
NG
Round 1
Round 2
Round 3
Motivation - example
R
1 2
NG
NG
NG
X
Total discard energy = 3 * Reception energy
Cost metric Hop count
Cij = 1 Transmission Energy
Cij = Tij
Transmission Energy based on farthest node Cij = (Tij + R) if j is the farthest
node from i = R otherwise
Cost metric
Transmission Energy based on farthest node with discard energy
Cij = (Tij+R+Li) if j is the farthest node from i
= R otherwise
Li = R * (#neighborsi - #tree childreni)
An Example
0
1
6 2
345
7
8 9
120.1
120.02
75.27
75.37
120.36
120.04
120.56
120.06
200.03
120.45 120.34
75.48 75.49
Hop count metric – SS-SPST
Stabilization time = 3 rounds
Energy consumed / bit = 5.95 micro J
0
1
6 2
345
7
8 9
1
1
1
1
1
1
1
1 1
Round 1
Round 2
Round 3
Transmission Energy metric – SS-SPST-T
Stabilization time = 4 rounds
Energy consumed / bit = 4.72 micro J
0
1
6 2
345
7
8 9
1.492
1.49
0.617
1.4909
1.491
4.051
1.5
0.619 0.6199
Round 1
Round 2
Round 3
0.618Round 4
Max Transmission Energy metric – SS-SPST-F
Stabilization time = 5 rounds
Energy consumed / bit = 3.392 micro J
0
1
6 2
345
7
8 9
0.05
0.05
0.617
0.05
0.05
4.101
1.55
0.05 0.05
Round 1
Round 2
Round 3
Round 40.05
Round 5
1.542
Max Transmission Energy + Discard Energy metric – SS-SPST-E
Stabilization time = 5 rounds
Energy consumed / bit = 3.29 micro J
0
1
6 2
345
7
8 9
0.05
0.05
0.657
0.05
0.05
4.101
1.55
0.05 0.05
Round 1
Round 2
Round 3
Round 4
0.05
Round 5
1.542
Summary
Metric # rounds Energy in micro J
SS-SPST 3 5.9512
SS-SPST-T 4 4.7279
SS-SPST-F 5 3.3922
SS-SPST-E 5 3.2959
Simulation Environment
Simulator - NS-2 Simulation area - 750 x 750 Simulation time - 1800 seconds # nodes - 50 Traffic rate – 64 Kbps # group nodes - 20
Performance Metrics
Packet delivery ratio #pkts received/#pkts transmitted
Energy consumed per packet delivered Total energy consumption/pkts
received End-to-end delay
Total delay per packet/#received nodes
Unavailability ratio Service interrupt time/simulation
time
Energy Spent – Different cost metrics
Packet Delivery Ratio – Different cost metrics
Unavailability Ratio – Different cost metrics
Packet Delivery Ratio – Different protocols
Energy Spent – Different protocols
Control Byte Overhead – Different protocols
Delay – Different protocols
Implementation
To check the correctness of the protocols
Implementation testing with 3 laptops working in ad hoc mode
Emulation – mobility, energy and bit error rate
Implementation
UtilityClasses
PacketListener
Event Handler
SS-SPST
Packet Handler
Send Receive
Conclusion & Future work
Energy saving using proposed cost metric
Cost of saving energy Nodes operating in sleep mode Testing real implementation with
many nodes
Questions?
Thank you!