Design of Full-Duplex Millimeter-Wave Integrated Access and Backhaul Networks

TL;DR

This paper explores the design of full-duplex millimeter-wave integrated access and backhaul networks, addressing self-interference mitigation and demonstrating near-double spectral efficiency compared to half-duplex systems.

Contribution

It introduces a hybrid precoding scheme with interference mitigation techniques tailored for mmWave FD-IAB networks, considering practical RF insertion loss and channel uncertainties.

Findings

Almost double spectral efficiency with low channel uncertainty

Effective self-interference cancellation using antenna, analog, and baseband techniques

Performance close to fully connected hybrid precoding systems

Abstract

One of the key technologies for the future cellular networks is full duplex (FD)-enabled integrated access and backhaul (IAB) networks operating in the millimeter-wave (mmWave) frequencies. The main challenge in realizing FD-IAB networks is mitigating the impact of self-interference (SI) in the wideband mmWave frequencies. In this article, we first introduce the 3GPP IAB network architectures and wideband mmWave channel models. By utilizing the subarray-based hybrid precoding scheme at the FD-IAB node, multiuser interference is mitigated using zero-forcing at the transmitter, whereas the residual SI after successfully deploying antenna and analog cancellation is canceled by a minimum mean square error baseband combiner at the receiver. The spectral efficiency (SE) is evaluated for the RF insertion loss (RFIL) with different kinds of phase shifters and channel uncertainty. Simulation results show that, in the presence of the RFIL, the almost double SE, which is close to that obtained from fully connected hybrid precoding, can be achieved as compared to half duplex systems when the uncertainties are of low strength.