PowerAware Routing in Ad Hoc Networks

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Power-Aware Routing in Ad Hoc Networks

• Presented By
• Amr El Mougy
• Under the Supervision of
• Dr. Glen Takahara

2
What is an Ad Hoc Network?

• Wide range of applications in fields such as
  military communications, emergency services and
  home/office networking
• Sensor networks are special types of Ad Hoc
  networks

3
Characteristics and Design Issues

• No fixed infrastructure required
• Dynamically changing topology
• Physical layer limitation (and limited bandwidth
  and quality)
• Multi-hop Communications
• Limited Security
• Energy Constrained Nodes

4
Power Saving in Ad Hoc Networks

• Physical Layer
• Optimizing power on the circuit level
• Powering-off components when not
  needed
• Transmitting at minimum power level
• Data Link Layer
• Effective retransmission schemes
• Turning off nodes when not
  transmitting or receiving
• Reduce collisions whenever possible
• Network layer
• Load balancing among nodes
• Maximizing network lifetime
• Minimize total transmitted power
  among routes
• Application Layer
• Use low complexity algorithms and
  software

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Shortest Path Routing

• DSDV
• Every node keeps a routing table to all
  destinations
• Routes are available on the spot
• Sequence numbers ensures freshness of routes
• Periodic and event-triggered updates

• AODV
• Path discovery is done by flooding the network
  with RREQ packets
• Sequence numbers ensures freshness of routes
• Nodes keep routing tables only for next hop to
  destination
• DSR
• Data packets contains addresses of each node
  from source to destination
• route cache enables multi-path routing

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Power-Aware Routing Protocols
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Maximizing Energy Saving
Minimum Total Transmission Power Routing (MTPR)
Minimize the Metric e ? P(n , n )
k-1
i
i1
i1

• Builds on top of proactive or reactive protocols
  and chooses a route that will minimize e

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Maximizing Energy Saving
Power Aware Routing Optimization (PARO)

• Use of intermediate nodes to reduce overall
  transmission power
• u(d) a.d c

a
a
d
Source
c
e
b
Destination
P(a,c) P(a,b) P(b,c)

• Stojmenovic and Lins modification,
• For each originating node B (either source or
  intermediate)
• P(B,D) u(r) v(s) where D is the
  destination node

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Maximizing Energy Saving
Location-Aided Power-Aware Routing (LAPAR)

• Use of relay regions R(s,r) where
• R(s,r) i d d d i?r
• p 1/d
• LAPAR adapts well to node mobility

2
2
2
d
1
sr
ri
si
2
r
s
d
2
R(s,r)
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Maximizing Energy Saving

• A Small subset of nodes might still be overused
  leading to network partitioning

B
E
D
A
C
F
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Power-Aware Routing Protocols
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Maximizing Network Lifetime
Minimum Battery Cost Routing (MBCR)

• Residual Battery is considered
• The path with the maximum remaining battery
  capacity is chosen
• For a route j, the battery cost R is
• R ? f (c )
• where f (c ) 1/c the inverse of the
  remaining battery at time t
• Thus the path with the minimum cost is chosen
• R minR j ? A
• A Route with little remaining battery capacity
  might still be chosen

D - 1
j
t
j
i
i
i0
t
t
i
i
j
i
13
Maximizing Network Lifetime
Maximum Survivability Routing (MSR)

• Drain rate is considered instead of only
  residual battery
• The cost of the route is defined as
• C ? u ? (1/T )
• where T is the nodes remaining power divided
  by its draining rate

1/ß
1/ß
ß
ß
i
i
R
i ? R
i ? R
i
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Maximizing Network Lifetime
Min-Max Battery Cost Routing (MMBCR)

• Avoid routes with least remaining battery
  capacity
• Battery cost for route j is
• R max f (c )
• Therefore we choose the path satisfying
• R minR j ? A
• Again, drain rate can be used instead of
  remaining battery capacity

t
j
i
i
i ? route j
j
i
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Maximizing Network Lifetime
Conditional Min-Max Battery Cost Routing (CMMBCR)

• Hybrid between minimum power consumption and
  maximizing network lifetime
• Define a battery threshold ?. Let A be the set
  containing all possible routes between the source
  and destination and let Q be the set containing
  all routes where all the nodes have power above
  the threshold
• if A n Q ? ?, choose the path with minimum total
  transmission power
• Otherwise, invoke MMBR scheme

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Power-Aware Routing Protocols
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Passive Energy Saving Protocols
Basic/Adaptive Fidelity Energy-Conserving
Algorithms (BECA/AFECA)

• Both algorithms work on top of on-demand routing
  protocols
• Save up to 50 percent of the power
• Nodes transition between three states

Active
After T of inactivity
Data to send/receive
a
Data to send
After T of no traffic
l
Listening
Sleeping
After T of sleeping
s

• In AFECA the sleeping time is adjusted based on
  node density

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Passive Energy Saving Protocols
Geographical Adaptive Fidelity (GAF)

• Could be implemented on top of on-demand routing
  protocols
• Uses geographical information to prolong
  sleeping time
• Network is divided into virtual grids that can
  communicate with each other. In each grid only a
  few nodes are active
• The three states now are leader, competing and
  slave

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Power-Aware Routing Protocols
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Topology Control Protocols

• The topology of the network is adjusted by
  adjusting the transmission power to maintain
  necessary connectivity

B
A
D
C
B
A
C
D
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Summary and Conclusions

• Many challenges face Ad Hoc networks and power
  saving can be done at every layer
• Minimum hop protocols achieve certain degree of
  power saving, even so they are not designed to do
  so.
• There are mainly four classifications for
  power-aware protocols
• The choice of the routing algorithm must depend
  on the application of the system

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References

• J. Li, D. Cordes and J. Zhang, Power-Aware
  routing protocols in Ad Hoc wireless networks,
  IEEE Wireless Communication, Vol. 12, December
  2005, Pages 69-81.
• C.-K Toh, Maximum battery life routing to
  support ubiquitous mobile computing in wireless
  Ad Hoc networks, IEEE Communications Magazine,
  Vol. 39, June 2001, pages138-147.
• S. Basagni, M. Conti, S. Giordano and I.
  Stojmenovic, Mobile Ad Hoc networking, John Wiley
  and Sons Inc., 2004.

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Questions?