Multiuser channel allocation algorithms achieving hard fairness

This work investigates the performance of combined orthogonal channel and antenna allocation algorithms in multiple-antenna multi-channel systems. In (I. Toufik et al, IEEE VTC2004) a max-min allocation algorithm is proposed for an N-user system with N parallel sub-channels. Here, we extend this algorithm to the multiple-antenna systems and compare its performance in two different transmission scenarios (spatial multiplexing and space time coding). The techniques are applicable, for instance, in MIMO systems using OFDMA systems with dynamic sub-carrier allocation. We show that multiuser diversity, and thus an increase of aggregate data rates with the size of the user population, can still be successfully achieved even under a hard fairness constraint. Moreover, multiple-antennas permit spatial multiplexing. The techniques considered here do not require phase information in the channel allocation process, which, from a practical point-of-view is particularly important for time-division duplex systems exploiting channel reciprocity.