M. Chowdhury, J. Nam, A. Goldsmith

In this work, it is shown that the “energy-coherence-time” of the wireless channel in a rich scattering environment increases with an increasing number of antennas. In particular, it can be much larger than the inverse of the Doppler associated with the propagation environment. This suggests that the frequency of adapting to changes in the channel quality can be orders of magnitude higher with large antenna arrays.