Full duplex radios

Abstract

This paper presents the design and implementation of the first inband full duplex WiFi radios that can simultaneously transmit and receive on the same channel using standard WiFi 802.11ac PHYs and in typical SNR regimes achieve close to the theoretical doubling of throughput. Our design uses a single antenna for simultaneous TX/RX (i.e., the same resources as a standard half duplex system). We also propose novel analog and digital cancellation techniques that cancel the self interference to the receiver noise floor, and therefore ensure that there is no degradation to the received signal. We prototype our design by building our own analog circuit boards and integrating them with a fully WiFi-PHY compatible software radio implementation. We show experimentally that our design works robustly in noisy indoor environments, and provides close to the expected theoretical doubling of throughput in practice.

5G Wireless Technologies- Future Generation Communication Technologies

“…Therefore, a full duplex radio had to employ procedures to terminate self-interference [14,15,16]. By means of benefit, the employment of SIC permits unified universal drifting, great amount of amenities, and low potential functions.…”

Numerical study on a rotationally-symmetrical dipole array antenna position for a MIMO full-duplex system

“…The combination of the MIMO technology and the full-duplex system is called the MIMO full-duplex system. However, it is well-known that the full-duplex system suffers from the so-called self-interference [3]. The self-interference problem leads to the saturation of the radio frequency (RF) front-end because the level of the transmitting signal is considerably higher than that of the receiving signal.…”

Compact Antennas With Reduced Self Interference for Simultaneous Transmit and Receive

“…This method achieves about 40 dB of isolation, however it brings several limitations: (i) the receive antenna should receive the 180 • out of phase signal only at the center frequency, (ii) the configuration of using multiple antennas is not feasible for handheld devices where space is limited,and (iii) use of multiple antennas creates nulls in the far field and degrades radiation pattern. To overcome the above shortcomings, a single antenna is used to transmit and receive simultaneously by incorporating a circulator combined with analog cancellation tools based on a balun, variable attenuators, and delay lines [11,12]. A circulator can achieve approximately 20 dB of added isolation in this manner, with the loss of an increase in device cost and size.…”