Adaptive MIMO Multichannel Beamforming with Cochannel Interference and Noise: Algorithm and Performance Analysis

We propose a novel low-complexity adaptive transmission scheme for multiple-input-multiple-output (MIMO) multichannel beamforming systems in the presence of cochannel interference. By measuring and exploiting the characteristics of the cochannel interference, the proposed adaptive algorithm jointly selects the active eigenmodes, the power allocation, and the modulation formats by utilizing a set of eigenvalue-based thresholds to maximize the spectral efficiency while meeting a target bit-error-rate (BER) constraint. We analyze the performance of the proposed scheme by deriving tractable expressions for the suspension probability and the error-free rate and demonstrate significant performance gains with respect to prior adaptive systems.