The capacity of multipath MIMO channels with uninformed transmitters

This paper considers the Shannon capacity of a space and time dispersive Multiple-Input Multiple-Output (MIMO) channel with multidimensional modulation. We assume a nonfading environment, and an unknown channel at the transmitter but known at the receiver. It is shown that the power allocation achieving capacity corresponds to a uniform power distribution among transmit antenna groups sharing the same signal subspace, determined by the space-time modulation format. Numerical results show that the capacity increases with the number of signal propagation paths, and also with the number of antennas.