Interference Suppression for Differential Cooperative D2D Communications with Multiple Antennas

In this paper, we investigate double differential detection (DD) for cooperative D2D communications using multiple antennas with unknown carrier frequency offsets. Most existing work in cooperative D2D communications assumes perfect channel knowledge at all devices and no carrier frequency offsets (CFO). However, accurate channel state information (CSI) can be difficult to obtain for fast varying channels while increases computational complexity in channel estimation, and commonly existing carrier offsets can greatly degrade the system performance. Therefore, a signal detection method based on double differential to remove the interference caused by CFO without the knowledge of CSI. To improve the performance of the cooperative D2D system, orthogonal space-time block codes (OSTBC) is applied at each transmitter. Simulation results show that the proposed DD scheme is effective in removing the carrier offsets, and full diversity order can be achieved with linear computational complexity.