The model is built upon the assumption that the probabil-

ity distribution of available destinations among the buered frames at

the Base Station (BS) is approximately the same as the probability

distribution of the trac arriving to the BS, this is, the amount of

trac directed to each MN with respect to the total trac load. This

assumption leads to a simple, but accurate, queueing model for Multi-

user MIMO systems that accounts for the impact of a nite number of

active MNs in non-saturated conditions. The model is easily applicable

to any Multi-user MIMO scenario given that the probability density

function of the post-processing SINR (Signal to Interference and Noise

Ratio) for each MN is known.