A random allocation scheme for SDMA systems is proposed with a goal of more efficient dynamic allocation. Based on theoreti cal analysis and derivation, the blocking probability of the proposed scheme is calculated and compared with those of the first duplicate (FD) and duplicate last (DL) schemes with different state-independent probabilities (p,) of acquring a dupicate channel successfully and 5 resources; moreover, a more realistic performance analysis of the random scheme is made with state-dependent p, in the SDMA/CDMA environment. The results show that the random scheme has a similar allocation performace to the FD and DL schemes, but is simpler than them in computation and scheduling.