In this paper, we study the space-time multiple access framework proposed in  for the MIMO forward link transmission, in a multipath-rich environment. The primary goal is to achieve high bandwidth efficiency employing multicarrier modulation, while the number of user-channels, rather than the individual's data rate, is to be maximized. In the proposed framework, we focus on a single spreading period, in which the data from different users are multiplexed using the space-time-frequency-diagonal (STFD) spreading sequences. It is shown that spectral efficiency of N users/Hz/sec could be achieved, where N is the number of transmit and receive antenna elements. Simulations results indicate that frequency diversity gain can be obtained with only linear-processing at the receiver.