Performance of Channel Inversion Schemes for Multi-User OFDMA

A novel multi-user diversity scheme for OFDMA (orthogonal frequency division multiplexing access) is described which alleviates the need of feedback and provides substantial improvements in non-cooperative environments. The algorithm exploits the reciprocity of the channel and enables a user to send reliably data at a prescribed rate knowing only its channel. Moreover, analytical expressions of the cell spectral efficiency are derived in the asymptotic regime (high number of carriers) for two filter types: matched filter and optimum filter. Discussions are also provided for various channel models