Ashok MantravadiVenugopal V. VeeravalliHarish ViswanathanSpectral efficiency of MIMO multiaccess systems with single-user decoding.382-394200321IEEE J. Sel. Areas Commun.3https://doi.org/10.1109/JSAC.2003.809699db/journals/jsac/jsac21.html#MantravadiVV03