E.Khan and C.Heneghan
A Closed Form Expression for the Ergodic Capacity of MIMO Systems
Multi-input Multi-output (MIMO) system are today regarded as one of the most
promising research areas in wireless communications. This is due to the fact
that MIMO channel can offer a significant capacity gain over traditional
Single-input single-output (SISO) channel. This paper presents the capacity of
an uncorrelated and correlated MIMO channel. The expression for the large system
MIMO capacity is calculated in closed form using replica analysis and Grassmann
variables. It is assumed that the receiver has perfect knowledge of the channel
but no such information is available at the transmitter. It is shown that for
large (but finite) number of antennas the capacity scales linearly with the
number of antennas. Our expression gives very good approximation of capacity
even for 2/3 antenna case. Besides this, using the same analysis we can find the
bounds on ergodic capacity when we have noisy channel estimate at the receiver
or even when there is co-channel interference (in addition to noise).