Subband bandwidth considerations for multiple-antenna multicarrier communications

We outline guiding principles for choosing the subband bandwidth of a multicarrier system with multiple antennas. Initially, we review considerations for the choice of bandwidth in fast-fading doubly dispersive channels. We append to these considerations those relevant to the use of multiple antennas for interference rejection in the wideband regime. To weigh the benefits of narrow subbands, which permit narrowband beamforming for better interference rejection and signal gain, against the cost of a multiplicity of subbands, which is principally that of a high peak-to-average power ratio, we introduce an achievable rate metric.