Measurements and analysis of multiuser MIMO-OFDM channels in campus environment

This paper describes a channel measurement campaign undertaken on the Macquarie University (MQ) campus, Sydney, Australia, based on a multiuser multiple-input multiple-output orthogonal frequency division multiplexing (MU-MIMO-OFDM) system, developed by Commonwealth Scientific and Industrial Research Organisation (CSIRO) and installed in MQ campus. The MU-MIMO-OFDM system consists of a central node with a twelve-element antenna array and up to six remote nodes each with a single antenna. This paper reports on the analysis of user spatial correlation and the measured MU-MIMO-OFDM system capacity for different scenarios in a campus environment. It was found that channels of users concentrated in a local area with limited scattering can be highly correlated, and thus careful user selection is needed when supporting multiple users in such a scenario by the system. Our results also indicate that a significant portion of the theoretical sum-rate predicted under i.i.d. Rayleigh channels can be achieved in various realistic environments, despite differences observed between the measured channels and the theoretical i.i.d. channels.