Optimum power allocation for multiuser OFDM with arbitrary signal constellations

Lozano Solsona, Angel; Tulino, Antonia M.; Verdú, Sergio

doi:http://dx.doi.org/10.1109/TCOMM.2008.060211

Optimum power allocation for multiuser OFDM with arbitrary signal constellations

Citation

Lozano A, Tulino A M, Verdu S. Optimum power allocation for multiuser OFDM with arbitrary signal constellations. IEEE Transactions on Communications. 2008; 56(5): 828-837. DOI 10.1109/TCOMM.2008.060211

Abstract

This paper formulates power allocation policies that maximize the region of mutual informations/nachievable in multiuser downlink OFDM channels. Arbitrary partitioning of/nthe available tones among users and arbitrary modulation formats, possibly different for/nevery user, are considered. Two distinct policies are derived, respectively for slow fading/nchannels tracked instantaneously by the transmitter and for fast fading channels known/nonly statistically thereby. With instantaneous channel tracking, the solution adopts the/nform of a multiuser mercury/waterfilling procedure that generalizes the single-user mercury//nwaterfilling introduced in [1, 2]. With only statistical channel information, in contrast,/nthe mercury/waterfilling interpretation is lost. For both policies, a number of limiting/nregimes are explored and illustrative examples are provided.