Self-Interference Cancellation Based Hybrid Beamforming Design for Full-Duplex mmWave Communication with Partially-Connected Structures

The ever increasing demand for throughputs in next-generation wireless communication systems has been put forward for satisfying the exponentially incremental data transmissions. Millimeter wave (mmWave), massive multipleinput multiple-output (MIMO) and full-duplex (FD) are three disruptive technologies to meet the throughputs requirement, which can supply abundant spectral resources, provide multiplexing gain in space, as well as allow simultaneous transmissions, respectively. In this paper, we consider combining these three enablers to form a FD mmWave massive MIMO communication system. Due to the high costs and power consumption of the massive amount of radio-frequency chains components, especially when working on mmWave frequencies, as well as the strong self-interference (SI) that significantly degrades the performance, we focus on the SI cancellation based hybrid beamforming design for the FD mmWave system with partially-connected structures. Resorting to null space projection, we propose our hybrid beamforming design to cancel the SI as well as consider the spectral efficiency (SE) performance. Numerical results verify that our proposed hybrid beamforming design can indeed improve the SE performance when the signal-to-noise ratio (SNR) and the number of RF chains are large enough.