Resource Allocation and System Design of Out-Band Based Integrated Access and Backhaul Network at mmWave Band

To enhance the coverage and network capacity of the mmWave based 5 G new radio (NR), integrated access and backhaul (IAB) network is recently envisioned as one of the promising network architectures. In this paper, we propose resource allocation algorithms to increase the backhaul capacity of IAB network and evaluate the performance of IAB network through geometric analysis. First, we propose a centralized resource allocation (CRA) algorithm for the case that IAB donor is available to acquire entire channel state information (CSI) and traffic load information of each IAB node. However, in order to overcome the high propagation loss of mmWave band, a densification of IAB node is necessary, which may induce the high computational complexity and require tremendous amount of CSI feedback load for the CRA scheme. To address this challenge, we discuss the distributed resource allocation (DRA) framework which can be individually operated at the each IAB nodes. On the other hand, we investigate the IAB network to get the insights for the system design by applying geometric analysis. Taking the property of stochastic geometry and hybrid beamforming at mmWave band into account, we derive the tractable approximation of co-channel interference (CCI). This expression allows us to obtain the insights to avoid the effect of CCI. Finally, numerical results demonstrate that our proposed algorithm can improve the performance for IAB network and our geometric analysis is valid.