Spectral Efficiency Analysis for mmWave Full Duplex Multihop IAB Networks

The availability of wider bandwidth in mmWave frequencies has made it an attractive option for future wireless communication. 3GPP Release 16 introduced Integrated Access and Backhaul (IAB), a cost-efficient solution for small cell deployments. Hybrid analog/digital beamforming is a promising approach to mitigate high path loss and enhance beamforming gain, as fully digital beamforming is impractical and fully analog beamforming has limitations in multiuser scenarios. We examined a multihop IAB network with nodes operating in full-duplex mode. Data transmissions occur on the backhaul uplink from the gNodeB (gNB) to the first IAB node and on the access downlink from the first IAB node to the first user. This process repeats from the first IAB node to the second IAB node and from the second IAB node to the second user. To reduce self-interference (SI) and improve spectral efficiency, we propose hybrid precoders and combiners. Simulations demonstrate that our hybrid beamforming method significantly outperforms existing models and approaches the upper bound of fully digital beamforming.