Full-duplex radios in 5G: Fundamentals, design and prototyping

The proliferation of smartphones, tablet PCs and laptops is continually boosting demand for higher throughput of mobile devices with advanced wireless network capabilities. To support such demand, fifth generation (5G) wireless communications are expected to provide 1000-fold greater throughput than 4G. Full-duplex radios simultaneously transmit and receive in the same frequency band. This chapter is devoted to designing and prototyping of full-duplex communication systems, with emphasis on various self-interference cancellation (SIC) schemes. The goal of digital SIC is to cancel residual self-interference after analog SIC, especially that originated from the non-line-of-sight reflections. Owing to the recent development of software-defined radio (SDR) platforms, prototyping has become a viable option for algorithm researchers. Synchronization is one of the key blocks to implementation of real-time wireless communication systems, especially full-duplex systems. The reference symbol (RS) is essential to estimating the channel for full-duplex radio. Channel estimation is performed for two channels: the self-interference channel and signal-of-interest channel.