—A single-carrier frequency-interleaved spread spectrum multiple access (SC-FI-SSMA), which we recently proposed, uses frequency-domain interleaving and MMSE-FDE to remove the uplink multi-user interference (MUI) while achieving the frequency diversity gain by assigning the orthogonal interleaving matrices to different users. However, in a multi-cell environment, the uplink capacity of SC-FI-SSMA may degrade due to the inter-cell interference. To improve the uplink bit error rate (BER) performance, transmit power control and site selection diversity techniques can be applied. In this paper, we evaluate the uplink capacity of SC-FI-SSMA to show that SC-FI-SSMA provides better uplink performance than DS-CDMA even in a multi-cell environment.