  This work considers an uplink wireless communication system where multiple
users with multiple antennas transmit data frames over dynamic channels.
Previous studies have shown that multiple transmit and receive antennas can
substantially enhance the sum-capacity of all users when the channel is known
at the transmitter and in the case of uncorrelated transmit and receive
antennas. However, spatial correlations stemming from close proximity of
transmit antennas and channel variation between pilot and data time slots,
known as channel aging, can substantially degrade the transmission rate if they
are not properly into account. In this work, we provide an analytical framework
to concurrently exploit both of these features. Specifically, we first propose
a beamforming framework to capture spatial correlations. Then, based on random
matrix theory tools, we introduce a deterministic expression that approximates
the average sum-capacity of all users. Subsequently, we obtain the optimal
values of pilot spacing and beamforming vectors upon maximizing this
expression. Simulation results show the impacts of path loss, velocity of
mobile users and Rician factor on the resulting sum-capacity and underscore the
efficacy of our methodology compared to prior works.
