Modeling for Geo-Routing in Multi-Hop Wireless Networks - Application and Multidisciplinary Aspects of Wireless Sensor Networks - page 147

Fig. 7.4 The 100-0% ppr transition contour for the UDG ( dotted line ) is depicted, superimposed
on the 50% ppr contour ( solid line ) for a spatially correlated shadow fading environment. Note
that the contours are not accurate or drawn to any scale

7.5 Packet Reception Probability Contour

For each and every realization of the random field x σ ( r ) such as the one shown in
Fig. 7.3b , the packet reception probability will now become an asymmetric contour
that resembles an “amoeba” in shape. This is depicted in Fig. 7.4 . We proceed to
perform simulations to establish under what circumstances the differences between
the two packet reception probability models (i.e., the “amoeba” and circularly
symmetric models) result in significantly different predictions for the performance
of geographic, position-based routing protocols.

7.6 Geographic/Position-Based Routing

In ad hoc networks, the task of finding and maintaining routes is nontrivial since
host mobility can result in unpredictable topology changes. In ad hoc networks,
“ Localized Routing Algorithms” have been proposed where nodes do not require
the complete network topological information to perform the routing task. More
precisely, nodes only require the position of itself and its one-hop neighbors, and
position of destination [ 13 ].
We assume in this project that each node has a low-power Global Positioning
System (GPS) receiver, which provides the position information of the node itself.
If GPS is not available, the distance between neighboring nodes can be estimated