  Enhanced mobile broadband (eMBB) and ultrareliable and low-latency
communications (URLLC) are two major expected services in the fifth-generation
mobile communication systems (5G). Specifically, eMBB applications support
extremely high data rate communications, while URLLC services aim to provide
stringent latency with high reliability communications. Due to their
differentiated quality-of-service (QoS) requirements, the spectrum sharing
between URLLC and eMBB services becomes a challenging scheduling issue. In this
paper, we aim to investigate the URLLC and eMBB coscheduling/coexistence
problem under a puncturing technique in multiple-input multiple-output (MIMO)
non-orthogonal multiple access (NOMA) systems. The objective function is
formulated to maximize the data rate of eMBB users while satisfying the latency
requirements of URLLC users through joint user selection and power allocation
scheduling. To solve this problem, we first introduce an eMBB user clustering
mechanism to balance the system performance and computational complexity.
Thereafter, we decompose the original problem into two subproblems, namely the
scheduling problem of user selection and power allocation. We introduce a
Gale-Shapley (GS) theory to solve with the user selection problem, and a
successive convex approximation (SCA) and a difference of convex (D.C.)
programming to deal with the power allocation problem. Finally, an iterative
algorithm is utilized to find the global solution with low computational
complexity. Numerical results show the effectiveness of the proposed
algorithms, and also verify the proposed approach outperforms other baseline
methods.
