Power Allocation for URLLC Using Finite Blocklength Regime in Downlink NOMA Systems

The non-orthogonal multiple access (NOMA) technique is now considered as a strong candidate for 5G mobile communications that enables greater multiuser capacity and user fairness through multiplexing in the power domain. The key primary benefit is the higher spectrum efficiency compared to orthogonal multiple access(OMA). As the NOMA systems have the high capacity and spectrum efficiency, it could be a solution for Ultra-reliable low latency communication(URLLC), which is one of several different types of use-cases with the most stringent latency and reliability requirements in 5G networks. To meet the requirements, efficient resource allocation should be implemented. In this paper, we consider downlink NOMA systems using finite blocklength (FBL) regime for efficient resource allocation. FBL is used to propose an efficient power allocation algorithm in the downlink NOMA systems. So the downlink NOMA system with the proposed power allocation algorithm is adopted for efficient transmission. We compare the proposed algorithm, the fixed power allocation, and OMA in the viewpoint of resource block usage and energy efficiency. The simulation results demonstrate the proposed algorithm shows better resource block usage and energy efficiency than the others.