Takashi Yamada Noritake Miyoshi Yoshihito Sakai Hideaki Kimura Makoto Tsubokawa Multilevel Transmission System Using Multiple LDs and Block Receiving Technique. 5524-5527 2008 GLOBECOM http://dx.doi.org/10.1109/GLOCOM.2008.ECP.1055 conf/globecom/2008 db/conf/globecom/globecom2008.html#YamadaMSKT08