MIMO Two-Way Relaying Networks with Carrier Offsets

In the paper, we investigate double differential detection (DD) for a two-way relaying network using multiple antennas with unknown carrier frequency offsets. The vast majority of existing research on two-way relaying hypotheses that all devices have perfect channel knowledge and no carrier frequency offsets (CFO). However, for fast changing channels, it is hard to receive certain channel state information (CSI), and the system capability is significantly reduced by reason of increasing the computational complexity of channel estimation and commonly existing CFOs. Accordingly, a signal detection method based on double differential is proposed to remove the interference caused by CFOs for a MIMO bi-directional relaying system. For superior system performance, all transmitters adopt orthogonal space-time block codes (OSTBC). Obviously, the simulation results turn out that the suggested DD scheme can not only remove the carrier offsets effectively without CSI knowledge, but also carry out full diversity order with acceptable linear computational complexity.