Self-Interference Cancellation: A Comprehensive Review from Circuits and Fields Perspectives

Abstract

Increased demand for higher spectrum efficiency, especially in the space-limited chip, base station, and vehicle environments, has spawned the development of full-duplex communications, which enable the transmitting and receiving to occur simultaneously at the same frequency. The key challenge in this full-duplex communication paradigm is to reduce the self-interference as much as possible, ideally, down to the noise floor. This paper provides a comprehensive review of the self-interference cancellation (SIC) techniques for co-located communication systems from a circuits and fields perspective. The self-interference occurs when the transmitting antenna and the receiving antenna are co-located, which significantly degrade the system performance of the receiver, in terms of the receiver desensitization, signal masking, or even damage of hardwares. By introducing the SIC techniques, the self-interference can be suppressed and the weak desired signal from the remote transmitter can be recovered. This, therefore, enables the full-duplex communications to come into the picture. The SIC techniques are classified into two main categories: the traditional circuit-domain SICs and the novel field-domain SICs, according to the method of how to rebuild and subtract the self-interference signal. In this review paper, the field-domain SIC method is systematically summarized for the first time, including the theoretical analysis and the application remarks. Some typical SIC approaches are presented and the future works are outlooked.

Performance Analysis of Multihop Full-Duplex NOMA Systems with Imperfect Interference Cancellation and Near-Field Path-Loss

“…We assume that . is the residual signals for , , at the th relay after both active and passive cancellation (Passive cancellation can be done by appropriately placing the transmit and receive antenna, i.e., at the two sides of the devices while active cancellation can be employed by using analog and digital SIC circuits [ 18 ]) and .…”

“…In fact, by concurrently transmitting and receiving signals, FD communications, theoretically, doubly improve spectral efficiency [ 16 ]. Although both FD and NOMA greatly facilitate the SE of the wireless networks, they suffer from the low signal-to-interference-plus-noise ratio (SINR) owing to strong self-interference [ 17 , 18 ]. Hence, to truly attain benefits from both NOMA and FD, ameliorating the SINR is mandatory, one of the promising solutions is to utilize multihop communications that improve the SINR by shortening the transmission distance [ 19 , 20 ].…”

Isolation Improvement Using the Field-Circuit Combined Method for In-Band Full-Duplex MIMO Antenna Arrays

“…When fullduplex antennas are used in MIMO antenna arrays, the antenna elements are closely arranged due to the limited space. Signal interference is generated between the receiving and transmitting antennas, and mutual coupling is generated between the receiving/transmitting antennas, which significantly deteriorate the performances of the wireless communication systems (including receiver performance, error rate, dynamic range, and channel capacity) [5][6][7]. Notably, 100 dB isolation between the transmitter and receiver is generally required for fullduplex systems, which is usually achieved by combining the antenna, analog and digital domains [8,9].…”

High-Isolated Full-Duplex Dongle Antenna Based on Even-Mode Suppression for B5G Communications

“…Such high isolation is usually achieved by a combination of antenna isolation enhancement, analog filtering, and digital interference cancellation [5]. Therefore, antennas with high isolations (> 25 db) are desired to relieve the pressure on the sequential processing and improve the dynamic range of the wireless connectivity [6,7].…”