Channel allocation algorithms for multi-carrier systems

Abstract

This study focuses on orthogonal channel allocation strategies, yielding multiuser diversity with a deterministic channel, for use in an N-user system with N parallel sub-channels. The techniques are applicable, for instance, in orthogonal frequency division multiple-access (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. Furthermore, we provide algorithms which perform channel allocation yielding a variable-rate with constant power and fixed-rate with variable power. We show the effect of system bandwidth (and thus sub-channel correlation) on multiuser diversity. 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.