Tiangao Gou Toshiaki Koike-Akino Philip V. Orlik Improved and Opportunistic Interference Alignment Schemes for Multi-Cell Interference Channels. 1-5 2012 VTC Spring https://doi.org/10.1109/VETECS.2012.6240343 conf/vtc/2012s db/conf/vtc/vtc2012s.html#GouKO12