Integrated Over-the-Air Computation and Non- Orthogonal Multiple Access Communication in Wireless Uplink Systems
Lifeng Mai, Hualiang Luo, Qi Zhang
Abstract
Future Internet-of-Things applications may require both high-quality wireless data aggregation and communication simultaneously. In this paper, we propose an integrated over-the-air computation (AirComp) and non-orthogonal multiple access (NOMA) communication scheme in a wireless uplink system, which consists of a data fusion center, a base station, and associated multiple users. Each user participates in AirComp and information transmission simultaneously. The data fusion center is responsible for wireless data aggregation and the base station is responsible for data collection of all users. Our aim is to minimize the computation mean square error (CMSE) at the data fusion center while satisfying the total transmission rate requirement at the base station. The formulated optimization problem is non-convex. To solve the problem, we propose a one-dimensional search based globally optimal solution, an alternating optimization based locally optimal solution, and a generalized Rayleigh quotient based globally optimal solution. Numerical results illustrate that although the locally optimal solution has the shortest average program execution time (PET), it achieves the suboptimal system performance. The generalized Rayleigh quotient based globally optimal solution, which addresses the CMSE minimization problem in a different manner, has much lower average PET than the one-dimensional search based globally optimal solution.