Capacity of Line-of-Sight MIMO Channels

Abstract

We establish an upper bound on the information-theoretic capacity of line-of-sight (LOS) multiantenna channels with arbitrary antenna arrangements and show that properly configured array-of-subarrays (AOSA) structures can attain, at least, 96.6% of such capacity at every signal-to-noise ratio (SNR). In the process, we determine how to configure the AOSAs as a function of the SNR. At low- and high-SNR specifically, AOSAs are seen to revert to simpler structures and to become capacity-achieving.