Capacity and positioning in dense scattering environments

We study the capacity scaling of a system where a source communicates to a destination with the help of several scatterers. Capacity expressions accounting for physical characteristics of the environment (topology, frequency band...) are provided and an asymptotic analysis is performed for an increasing size of the dense scattering environment. The capacity is shown to reach a saturation level in the asymptotic regime, suggesting a capacity-delay trade-off. Moreover the saturation point depends on the positioning of scatterers, in particular in wide band systems where topology impacts capacity in terms of both pathloss and delays. Waiting very long for retransmissions from an infinite number of scatterers is not worth and a few well located scatterers around source and destination lead to better performances than more scatterers uniformly distributed on a square area between source and destination.