Full Duplex Integrated Access and Backhaul for 5G NR: Analyses and Prototype Measurements

Researchers for the third-generation partnership project (3GPP) have been exploring — as a cost-effective alternative to wired backhaul — integrated access and backhaul (IAB) frameworks for 5G new radio (NR). A promising solution for this framework is the integration of full duplex (FD) technologies to enhance the spectral efficiency and efficiently utilize network resources. This approach, which we refer to as FD IAB, involves a significant technical challenge — self-interference (SI) in the IAB framework. In fact, this challenge casts doubt over the performance and feasibility of FD IAB. In this article, we introduce the FD IAB framework and its enabling technologies and also evaluate the framework's link-level SI reduction and system-level downlink throughput performance. Thereafter, we validate the attenuation level in the SI channel with antenna separation and high directional gain through 28 GHz hardware prototype measurements. Our numerical evaluations and hardware prototype measurements confirm that FD IAB represents a promising framework for 5G NR.