Information Technology Reference
In-Depth Information
Chapter 7
Modeling for Geo-Routing in Multi-Hop
Wireless Networks
Adnan Khan, Costas Constantinou, and Ivan Stojmenovic
Existing routing and broadcasting protocols for ad hoc networks assume an ideal
physical layer. In reality, an accurate representation of physical layer is required for
analysis and simulation of multi-hop networking in sensor and ad hoc networks. This
work describes a physically realistic model for the log-normal correlated shadow fad-
ing loss, and investigates the importance of the shadowing correlation length on
designing protocols for ad hoc and sensor networks. Nodes that are geographically
proximate often experience similar environmental shadowing effects and can have
correlated fading. This work also describes an evaluation procedure, which produces
statistically meaningful results over a large number of realizations of multi-hop net-
works. This procedure takes into account the overall path loss (shadow fading and
median path loss) based for antennas working at 2.4 GHz with heights ranging from
0.5 to 1.8 m. Finally, we analyze and compare the performance of the localized
position-based greedy algorithm used for Unit Disk Graph (UDG) and the probabi-
listic position-based greedy algorithm on the proposed model for different values of
standard deviation (s) of shadow fading to show the importance of both the shadow
fading and correlation length while designing the protocols for ad hoc networks.
7.1
Introduction
The operation, performance, and limitations of multi-hop wireless networks cannot
be understood through theory and simulations based on ever-improving models of
point-to-point radio propagation channels. This assertion is intuitively self-evident,
as the operation of a spatially extended wireless peer-to-peer network is contingent
on the spatio-temporally correlated (near) error-free operation of multiple wireless
point-to-point links that are “embedded” in the same geographical space.
It has long been recognized that the degree of realism of the radio propa-
gation environment in multi-hop networks needs to be significantly improved.
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