Meng Wang Daniel E. Quevedo Graham C. Goodwin Joint Data Detection and Channel Estimation for MIMO-OFDM Systems via EM Algorithm and Sphere Decoding. 2006 conf/globecom/2006 GLOBECOM http://dx.doi.org/10.1109/GLOCOM.2006.539 db/conf/globecom/globecom2006spc.html#WangQG06