Chapter 15: Ad-Hoc Networks

Patrick Tortelier, France T l com R&D,

France

1 Introduction

Just as the Greeks had felt the need to encapsulate their notion of a human being as ˜an animal which lives in a polis ( zoon politikon ) , in the same way one could define current mankind as the only animal which communicates with its like at distances much greater than those that its senses can achieve “ hearing, seeing, sense of smell (soon to be possible) etc. Thus, if one limits oneself only to technologies of wireless communication, one can note that if the first systems transmitted speech only, present day and more especially future systems will make it possible to see the interlocutor (transmission of animated images).

There is also a scheme of communication where source and recipient are the same person at two different moments: for example when we note the hour and the place of an appointment, a telephone number to be recalled, a list of tasks to be carried out i.e. all kinds of personal data which we need to available for future use. Personal numerical assistants help us in this task.

A last point is that, even if multimedia traffic is today rather asymmetrical (the flow towards the user being greater than that emitted by the user ), multiplication of the means of creation of numerical content (images, sound, videos ) or of their replication(hacking) and the development of the peer to peer networks change this situation.

A consequence of that is that we are surrounded by an increasing number of increasingly sophisticated objects, which are supposed to make our personal life simpler, more lucid or more creative, so that technologies, which yesterday were reserved for laboratories, can be seen today in our living rooms. One finds a PC in every home, often a printer, personal assistants, CD engravers, DVD readers, and kits of satellite reception . All these objects require a number of cables, either to feed them on the sector, or to interconnect them or to the network, and one finds oneself quickly in the midst of a forest of not very aesthetic cables.