Multilayer Orthogonal Beamforming for Priority-Guaranteed Wireless Communications
To utilize the benefits of cellular systems, wireless Machine-To-Machine (M2M) communications over cellular systems are being widely considered. In order to support efficient spectrum sharing between M2M devices and normal mobile users, in this paper, the authors propose a Multilayer Orthogonal BeamForming (MOBF) scheme forM2M communications over Orthogonal Frequency Division Multiple Access (OFDMA-) based cellular systems. Using MOBF, each subcarrier in OFDMA systems could be efficiently reused by both normal mobile users and machine-type devices which are organized into multiple virtual layers. The users located in higher layers (e.g., mobile users) are not to be interfered by those in lower layers (e.g., machine devices).