Full duplex communications [Guest Editorial]

With the rapidly growing demand for mobile applications, future wireless networks are facing considerable challenges in spectral efficiency. To deal with it, many techniques have been developed recently. Among them, in-band full duplex (IBFD), which enables a device to transmit and receive simultaneously at the same frequency, has ignited great interest from both academia and industry. IBFD can potentially double the spectral efficiency in the physical layer and also bring many advantages in high-layer design. However, to fulfill the minimum performance requirement for the current cellular networks, self-interference cancellation in IBFD communications is still a great challenge to the physical layer design. In addition, some system-level protocols must be redesigned since devices need to send and receive signals at the same frequency simultaneously.