  In this paper, we introduce a backscatter assisted wirelessly powered mobile
edge computing (MEC) network, where each edge user (EU) can offload task bits
to the MEC server via hybrid harvest-then-transmit (HTT) and backscatter
communications. In particular, considering a practical non-linear energy
harvesting (EH) model and a partial offloading scheme at each EU, we propose a
scheme to maximize the weighted sum computation bits of all the EUs by jointly
optimizing the backscatter reflection coefficient and time, active transmission
power and time, local computing frequency and execution time of each EU. By
introducing a series of auxiliary variables and using the properties of the
non-linear EH model, we transform the original non-convex problem into a convex
one and derive closedform expressions for parts of the optimal solutions.
Simulation results demonstrate the advantage of the proposed scheme over
benchmark schemes in terms of weighted sum computation bits.
