Delay Minimization in Wireless Powered Mobile Edge Computing With Hybrid BackCom and AT

Abstract

Wireless powered mobile edge computing (MEC) leveraging hybrid passive backscatter communications (BackCom) and active transmissions (AT) for efficient data offloading has been investigated in Internet of Things (IoT) networks, where however the delay minimization problem has not been sufficiently studied. In this letter, we propose to minimize the overall delay for data offloading and computing of all IoT nodes in a hybrid BackCom-AT based wireless powered MEC network. We formulate an optimization problem to jointly optimize the operation time of a power beacon, and the computing frequency, transmit power, and portions of task bits for BackCom offloading, AT offloading and local computing of each IoT node. By introducing auxiliary variables and slack variables, the formulated non-convex optimization problem is transformed into an equivalent but more tractable form and is optimally solved by our proposed bisection-based iterative algorithm (BBIA). Computer simulations verify the quick convergence of the BBIA, and show that our proposed algorithm achieves a much shorter overall delay of all IoT nodes than the baseline schemes.