  This paper considers the minimization of the offloading delay for
non-orthogonal multiple access assisted mobile edge computing (NOMA-MEC). By
transforming the delay minimization problem into a form of fractional
programming, two iterative algorithms based on Dinkelbach's method and Newton's
method are proposed. The optimality of both methods is proved and their
convergence is compared. Furthermore, criteria for choosing between three
possible modes, namely orthogonal multiple access (OMA), pure NOMA, and hybrid
NOMA, for MEC offloading are established.
