Routing is a challenging problem for wireless ad hoc networks, especially when the nodes are mobile and spread so widely that in most cases multiple hops are needed to route a message from one node to another. In fact, it is known that any online routing protocol has a poor performance in the worst case, in a sense that there is a distribution of nodes resulting in bad routing paths for that protocol, even if the nodes know their geographic positions and the geographic position of the destination of a message is known. The reason for that is that radio holes in the ad hoc network may require messages to take long detours in order to get to a destination, which are hard to find in an online fashion.
To answer this question, we consider a hybrid communication model. A Hybrid Communication Network has been introduced in different contexts @cite_9 @cite_13 . To the best of our knowledge, we are the first ones that consider these types of networks for the purpose of finding paths in ad hoc networks.
@cite_9 @cite_13
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In this article, some considerations are presented about the way several well-known industrial networks (based on both fieldbus and industrial Ethernet solutions) can be practically extended with wireless subnetworks that rely on popular technologies, such as IEEE 802.11 and 802.15.4. This results in hybrid networks, which are able to combine the advantages of both wired and wireless solutions. In particular, advantages and drawbacks of several interconnection techniques are highlighted and, depending on the wired networks specifically taken into account, some hybrid configurations that are able to cope in a satisfactory way with the tight timing requirements often imposed by industrial control systems are suggested. The present paper outlines features of communications via fibre optic cable, satellite transponders, microwave links and an integrated hybrid system using a mix of the above media. Hybrid communications will play a major role in all transactions of various countries and particularly in the monitoring and control of power systems. The paper also outlines the telemetry systems and sensors which need to be integrated with power distribution systems for online information flow to a central command post for preventive and corrective actions.