Capacity Bounds for Peak-Constrained Multiantenna Wideband Channels

Bounds are derived on the noncoherent capacity of a very general class of multiple-input multiple-output fading channels that are selective in time and frequency as well as correlated in space. The bounds apply to peak-constrained inputs; they are explicit in the channel's scattering function, are useful for a large range of bandwidth, and allow one to coarsely identify the capacity-optimal combination of bandwidth and number of transmit antennas. Furthermore, a closed-form expression is obtained for the rst-order Taylor series expansion of capacity in the limit of innite bandwidth. From this expression, it is concluded that in the wideband regime: (i) it is optimal to use only one transmit antenna when the channel is spatially uncorrelated; (ii) rank-one statistical beamforming is optimal if the channel is spatially correlated; and (iii) spatial correlation, be it at the transmitter, the receiver, or both, is benecial.

• Type: Journal
• Year: 2008
• Where: CORR
• Authors: Ulrich G. Schuster, Giuseppe Durisi, Helmut Bölcskei, H. Vincent Poor
• Keywords: CORR 2008, Education, Multiple-input Multiple-output, Noncoherent Capacity, Peak-constrained Inputs