The study presented in this paper underlines the capacity increase resulting from the joint use of multicarrier (MC) adaptive modulation techniques and MC-CDMA receiver in the context of beyond 3G systems. The performance enhancement due to such near optimal rate and power adaptation decreases with diversity order. Moreover, results obtained through two different kinds of wireless channels (ETSI BRAN A and C) highlight convergence phenomena, independent of initial channel diversity order. Finally, complete single user detection (SUD) techniques are compared in tit is context of adaptive modulation.