Low Complexity Hybrid Beamforming for mmWave Full-Duplex Integrated Access and Backhaul

TL;DR

This paper proposes a low complexity hybrid beamforming algorithm for mmWave full-duplex integrated access and backhaul, improving spectral efficiency by effectively canceling self-interference and optimizing beamforming design.

Contribution

It introduces a novel hybrid beamforming algorithm for full-duplex IAB nodes, with derivations of digital beamforming bounds and comprehensive simulation comparisons.

Findings

Significant reduction in self-interference power.

Increase in sum spectral efficiency.

Hybrid beamforming outperforms conventional methods.

Abstract

We consider an integrated access and backhaul (IAB) node operating in full-duplex (FD) mode. We analyze simultaneous transmission from the New Radio gNB to the IAB node on the backhaul uplink, IAB node to a user equipment (UE) on the access downlink, and IAB transmitter to the IAB receiver on the self-interference (SI) channel. Our contributions include (1) a low complexity algorithm to jointly design the hybrid analog/digital beamformers for all three nodes to maximize the sum spectral efficiency of the access and backhaul links by canceling SI and maximizing received power; (2) derivation of all-digital beamforming and spectral efficiency upper bound for use in benchmarking; and (3) simulations to compare full vs. half duplex modes, hybrid vs. all-digital beamforming algorithms, proposed hybrid vs. conventional beamforming algorithms, and spectral efficiency upper bound. In simulations, the proposed algorithm shows significant reduction in SI power and increase in sum spectral efficiency.