In a non-partitioned ad-hoc network, there exists at least
one path for a node to communicate with any other node. So
theoretically, any node can reach any other node through a
random forwarding path. However, the power consumption
along different paths varies, due to its dependence on
variations of distance between directly communicating
nodes and noise interference levels. The greater the values
these parameters hold, the larger amount of power is
demanded to transmit. Minimum total transmission energy,
such as MTPR, focuses on end-to-end energy efficiency.
Generally, the route selected by conserving energy is the
shortest distance path or minimum hop path. Even though
some nodes may be dissipating more energy due to
dynamics of link characteristics such as distance or error
rate, the end-to-end shortest path naturally leads to
conservation of energy in transmission.
The majority of energy efficient routing protocols for
MANET try to reduce energy consumption by means of an
energy efficient routing metric, used in routing table
computation instead of the minimum-hop metric. This way,
a routing protocol can easily introduce energy efficiency in
its packet forwarding. These protocols try either to route
data through the path with maximum energy bottleneck, or
to minimize the end-to-end transmission energy for packets,
or a weighted combination of both. A first approach for
energy-efficient routing is known as MTPR. That
mechanism uses a simple energy metric, represented by the
total energy consumed to forward the information along the
route. This way, MTPR reduces the overall transmission
power consumed per packet, but it does not directly affect
the lifetime of each node (because it does not take into
account the available energy of network nodes). However,
minimizing transmission energy only differs from shortesthop
routing if nodes can adjust transmission power levels, so
that multiple short hops are more advantageous, from an
energy point of view, than a single long hop. In 802.11 we
do not have access to this capability, so that, in a fixed
transmission power context, this metric corresponds to a
Shortest Path routing.
In a non-partitioned ad-hoc network, there exists at leastone path for a node to communicate with any other node. Sotheoretically, any node can reach any other node through arandom forwarding path. However, the power consumptionalong different paths varies, due to its dependence onvariations of distance between directly communicatingnodes and noise interference levels. The greater the valuesthese parameters hold, the larger amount of power isdemanded to transmit. Minimum total transmission energy,such as MTPR, focuses on end-to-end energy efficiency.Generally, the route selected by conserving energy is theshortest distance path or minimum hop path. Even thoughsome nodes may be dissipating more energy due todynamics of link characteristics such as distance or errorrate, the end-to-end shortest path naturally leads toconservation of energy in transmission.The majority of energy efficient routing protocols forMANET try to reduce energy consumption by means of anenergy efficient routing metric, used in routing tablecomputation instead of the minimum-hop metric. This way,a routing protocol can easily introduce energy efficiency inits packet forwarding. These protocols try either to routedata through the path with maximum energy bottleneck, orto minimize the end-to-end transmission energy for packets,or a weighted combination of both. A first approach forenergy-efficient routing is known as MTPR. Thatmechanism uses a simple energy metric, represented by thetotal energy consumed to forward the information along theroute. This way, MTPR reduces the overall transmissionpower consumed per packet, but it does not directly affectthe lifetime of each node (because it does not take intoaccount the available energy of network nodes). However,minimizing transmission energy only differs from shortesthoprouting if nodes can adjust transmission power levels, sothat multiple short hops are more advantageous, from anenergy point of view, than a single long hop. In 802.11 wedo not have access to this capability, so that, in a fixedtransmission power context, this metric corresponds to aShortest Path routing.
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