Impacts of Angles-of-Arrival on the Performance of Space-Constrained MIMO Antenna Array

With an infinite number of antennas deployed in the space-constrained environment, limits of the measures for the uplink multiple-input-multiple-output (MIMO) diversity system, i.e., the conditional long-term signal-power-to-interference-power ratio (
$\text{SIRP}_{c}$
) and the conditional long-term signal amplitude to the square root of the interference power ratio (
$\text{SAPR}_{c}$
) given the angles-of-arrival (AOAs) of the line-of-sight (LOS) signal components, are derived for users in correlated Ricean fading channels. The impacts of the user AOAs on these measures are discussed. Furthermore, the asymptotic user achievable spectral efficiency and bit error rate are derived using the
$\text{SIRP}_{c}$
and
$\text{SARP}_{c}$
, respectively, which indicates these performance indices vary with the AOAs of the user signals. We point out the LOS components, which dramatically change the system measure and performance with different AOAs, are sometimes beneficial. Results show by avoiding picking users located in the same direction of the antenna array, the correlated Ricean fading scenario can achieve superior performance to that of the correlated Rayleigh fading scenario.