Link reliability analysis in ad hoc networks
Journal
Proceedings of XII telekomunikacioni forum TELFOR
Date Issued
2004
Author(s)
Cilku, Bekim
Grnarov, Aksenti
Abstract
Mobile Ad-hoc NETworks (MANET) have become more
and more popular, during the last ten years. Mobile hosts such
as notebook computers are now easily affordable and are
becoming quite common in everyday business and personal
life. At the same time, network connectivity options for use
with mobile hosts have increased dramatically, including
support for a growing number of wireless networking
products based on radio and infrared. With this type of
mobile computing equipment, there is a natural desire and
ability to share information between mobile users.
MANETs are suitable for situations where infrastructure
is either not available, not trusted, or should not be relied on
in times of emergency, like in critical mission applications,
wherein fault tolerance is of great importance. For wireless
(and wire line) networks, the network’s ability to avoid or
cope with failure is measured in three ways: reliability,
availability and survivability, all of which have long been
important areas of research [1]. Because of its importance, in
this paper we investigate the link reliability for ad hoc
networks, which can be used as important global measure of
performances of ad hoc networks. It also can be utilized to
improve localized route repairs by the means of connection
mean time to failure (MTTF) as a parameter that allows
predicting of the link expiration time (LET). Consequently
global connection repairs are more seldom necessary, since
the route maintenance routine of the routing algorithm could
create disjoint bypass routes in advance based on calculated
connection mean time between failures.
The previous work of ad hoc network reliability includes
work on calculating link expiration times (LET) as in [2],
where statistical LET in mobile ad hoc networks is reviewed.
The authors predict the probability that a link between two
nodes exists at time t2, in case the link existed at the starting
time t0. They use the random waypoint model as a basic
movement model. No forecasts about the duration of
uninterrupted link can be made, since the link may cease to
exists at time t1 with t0 < t1 < t2. In [3] prediction-based link
availability estimation is introduced, while [4] gives a
statistical derivation to forecast the average distance when the
routing node is within the scope of the two other nodes. With
these statistical calculations, the paper investigates the
possibility of predictions of the average link expiration times
and deviations for different node velocities, independent from
the nodes radio transmission ranges and the distances
between each other. In [5] a mobility prediction, which allows
the creation of new routes in advance for mobile ad hoc
networks, is introduced. The routing algorithm determines
when a node will shortly leave the proximity of another node
and can handoff the connection. Unfortunately this approach
requires data from an external global positioning system (GPS) interface to determine the position, the velocity and the
moving direction of all nodes plus a synchronized clock in all
nodes. Qin and Kunz [6] perform a prediction of link
breakage time using the mobile node's signal power strength
from the received packets. The source node can perform a pro
active route rebuild to avoid disconnection. Sadagopan at al.
[7] examine the varying of the statistics of path durations
including PDFs with parameters such as mobility model,
relative speed, number of hops and radio range. They suggest
that at moderate and high velocities the exponential
distribution with appropriate parameterizations is a good
approximation of the path duration distribution for a range of
mobility models.
In this paper a link reliability model for two hop ad hoc
networks is presented. The main motivation for this work is to
use this model for MTTF calculation for a given link, which
can be used to forecast the local route repairs. The prediction
of link breakage is made on statistical basis and accordingly
does not require additional devices like GPS or some special
features in the wireless receiver that will enable measurement
of the signal strength. The proposed model is validated
through series of simulations using NS-2 simulator and
application of proposed model is also presented.
and more popular, during the last ten years. Mobile hosts such
as notebook computers are now easily affordable and are
becoming quite common in everyday business and personal
life. At the same time, network connectivity options for use
with mobile hosts have increased dramatically, including
support for a growing number of wireless networking
products based on radio and infrared. With this type of
mobile computing equipment, there is a natural desire and
ability to share information between mobile users.
MANETs are suitable for situations where infrastructure
is either not available, not trusted, or should not be relied on
in times of emergency, like in critical mission applications,
wherein fault tolerance is of great importance. For wireless
(and wire line) networks, the network’s ability to avoid or
cope with failure is measured in three ways: reliability,
availability and survivability, all of which have long been
important areas of research [1]. Because of its importance, in
this paper we investigate the link reliability for ad hoc
networks, which can be used as important global measure of
performances of ad hoc networks. It also can be utilized to
improve localized route repairs by the means of connection
mean time to failure (MTTF) as a parameter that allows
predicting of the link expiration time (LET). Consequently
global connection repairs are more seldom necessary, since
the route maintenance routine of the routing algorithm could
create disjoint bypass routes in advance based on calculated
connection mean time between failures.
The previous work of ad hoc network reliability includes
work on calculating link expiration times (LET) as in [2],
where statistical LET in mobile ad hoc networks is reviewed.
The authors predict the probability that a link between two
nodes exists at time t2, in case the link existed at the starting
time t0. They use the random waypoint model as a basic
movement model. No forecasts about the duration of
uninterrupted link can be made, since the link may cease to
exists at time t1 with t0 < t1 < t2. In [3] prediction-based link
availability estimation is introduced, while [4] gives a
statistical derivation to forecast the average distance when the
routing node is within the scope of the two other nodes. With
these statistical calculations, the paper investigates the
possibility of predictions of the average link expiration times
and deviations for different node velocities, independent from
the nodes radio transmission ranges and the distances
between each other. In [5] a mobility prediction, which allows
the creation of new routes in advance for mobile ad hoc
networks, is introduced. The routing algorithm determines
when a node will shortly leave the proximity of another node
and can handoff the connection. Unfortunately this approach
requires data from an external global positioning system (GPS) interface to determine the position, the velocity and the
moving direction of all nodes plus a synchronized clock in all
nodes. Qin and Kunz [6] perform a prediction of link
breakage time using the mobile node's signal power strength
from the received packets. The source node can perform a pro
active route rebuild to avoid disconnection. Sadagopan at al.
[7] examine the varying of the statistics of path durations
including PDFs with parameters such as mobility model,
relative speed, number of hops and radio range. They suggest
that at moderate and high velocities the exponential
distribution with appropriate parameterizations is a good
approximation of the path duration distribution for a range of
mobility models.
In this paper a link reliability model for two hop ad hoc
networks is presented. The main motivation for this work is to
use this model for MTTF calculation for a given link, which
can be used to forecast the local route repairs. The prediction
of link breakage is made on statistical basis and accordingly
does not require additional devices like GPS or some special
features in the wireless receiver that will enable measurement
of the signal strength. The proposed model is validated
through series of simulations using NS-2 simulator and
application of proposed model is also presented.
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