6 Conclusion

After having briefly described electromagnetic waves we presented the various mechanisms of propagation (reflection, transmission, diffraction , scattering etc) as well as the properties of the channel (attenuation, variability, selectivity). The selectivity of the channel is defined starting from parameters deduced from the average delay profile (average delay, delay spread, delay interval and delay window, correlation bandwidth). These various parameters make it possible to characterise the propagation medium necessary for the definition and deployment of the communicating objects.

In the last part are presented the various models for the deployment of the mobile systems and communicating objects in various environments (rural, mountainous, suburban, urban, interior of buildings ) and various types of cell (macrocell, small cell, microcell and pico- cell ) by primarily limiting us to the models with narrow band . Moreover, more details concerning these various models can be obtained in the literature [LAGRANGE, 2000]. The broadband models such as path models (COST 207, ATDMA [RACE, 1994]. IUT-R, CSELT), representation models (model of channel recorded in deterministic propagation) and geometrical models were not approached.