Distributed scattering in radio channels and its contribution to MIMO channel capacity

A well accepted radio channel model approximates the radio channel impulse response by a superposition of a finite number of propagation paths. Wideband radio channel measurements can be approximated using concentrated propagation paths with an accuracy of close to 100% down to only 30% or less, depending on the scenario. For this reason it has been proposed to extend the data model by an additional component describing the distributed scattering (dense multipath component, DMC) of the radio channel. The model for the DMC is parameterized by three parameters, a base delay, the coherence bandwidth or delay-spread, and the attenuation factor of the dense multipath component. It is shown in this paper that the distributed scattering contributes significantly to the capacity of the MIMO-wideband radio channel. In fact it can be observed in channel sounding measurements that the distributed scattering can contribute more to the channel capacity than the concentrated propagation paths.