  We analyze an uplink of a fast flat fading MIMO-CDMA channel in the case
where the data symbol vector for each user follows an arbitrary distribution.
The spectral efficiency of the channel with CSI at the receiver is evaluated
analytically with the replica method. The main result is that the hierarchical
decoupling principle holds in the MIMO-CDMA channel, i.e., the MIMO-CDMA
channel is decoupled into a bank of single-user MIMO channels in the many-user
limit, and each single-user MIMO channel is further decoupled into a bank of
scalar Gaussian channels in the many-antenna limit for a fading model with a
limited number of scatterers.
