Jihoon Park Przemyslaw Pawelczak Pål Grønsund Danijela Cabric Subchannel Notching and Channel Bonding: Comparative Analysis of Opportunistic Spectrum OFDMA Designs http://arxiv.org/abs/1007.5080 2010 CoRR abs/1007.5080 db/journals/corr/corr1007.html#abs-1007-5080