Multi-antenna transmission technology: has become the most important and indispensable technology in our 5G research. A series of high-order multiple-input multiple-output arrays are converted from two-dimensional to three-dimensional and from passive to active. At the same time, the same frequency full duplex technology can transmit signals bidirectionally on the same physical channel. Therefore, co-frequency full duplex technology is considered to be an effective technology to improve spectrum utilization. This technology can realize two-way transmission of signals on the same physical channel. Transmission means eliminating the interference of the transmitter signal at the receiving end of the duplex node and receiving a signal of the same frequency from another node on the transmitter signal. This can effectively improve the spectrum utilization rate and improve the flexibility and stability of the mobile communication network.