Capacity of line-of-sight MIMO channels

We establish an upper bound on the informationtheoretic capacity of line-of-sight (LOS) multiantenna channels with arbitrary antenna arrangements and identify array structures that, properly configured, 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 arrays as a function of the SNR. At low- and high-SNR specifically, the configured arrays revert to simpler structures and become capacity-achieving.H. Do and N. Lee are supported by the Samsung Research Funding & Incubation Center of Samsung Electronics under Project SRFC-IT1702-04. Prof. Lozano is supported by the European Research Council under the H2020 Framework Programme/ERC grant agreement 694974, and by MINECO’s Projects RTI2018-102112 and RTI2018-101040