Joint Resource Block Allocation and Beamforming with Mixed-Numerology for eMBB and URLLC Use Cases

Mixed-numerology has been proposed in the Third Generation Partnership Project (3GPP) standard for the fifth generation (5G) wireless networks, where flexible subcarrier spacing (SCS) can be applied to support uses cases with different quality-of-service (QoS) requirements. In this paper, we study the joint design of resource block allocation and beamforming with mixed-numerology for enhanced mobile broadband (eMBB) and ultra-reliable low-latency communications (URLLC) use cases. We consider multiple multi-antenna base stations (BSs) cooperatively provide services to the users. By using beamforming, inter-user interference can be mitigated and a resource block can be utilized by more than one user. Short packet transmission is considered for URLLC users to satisfy their low-latency requirements. We formulate a mixed-integer nonlinear programming problem to maximize the aggregate throughput of eMBB users while guaranteeing the throughput, reliability, and latency requirements of URLLC users. We propose a low-complexity algorithm, which leverages fractional programming and successive convex approximation (SCA), to obtain the solutions. Simulation results show that our proposed algorithm can improve the aggregate eMBB throughput by 30% compared with the fixed-numerology based approach.