Partial zero forcing for multi-way relay networks

The ever increasing demands for mobile Internet access have resulted a significant growth in bandwidth usage. Multi-way relay networks (MWRNs) can address this challenge by improving the system spectral efficiency. In this work, we further improve the spectral efficiency of MWRNs by proposing a novel linear beamforming design, namely partial zero-forcing (PZF), for MWRNs with a multiple-input-multiple-output relay. Compared to zero-forcing (ZF), in PZF, the constraints on the relay beamforming are relaxed such that only partial user-interference, instead of all, is canceled at the relay. After receiving the relay's signal, the users eliminate the remaining interferences through self-interference and successive interference cancellation. By taking such two-stage interference cancellation, PZF better exploits the degrees-of-freedom in MWRNs and achieves higher data rates than ZF.