On the Data Freshness for Industrial Internet of Things With Mobile-Edge Computing

This article studies the freshness of information with aid Age Information (AoI) in Industrial Internet Things (IIoT), which plays a vital role to ensure quality and timely delivery data services. To reduce AoI, we leverage mobile-edge computing (MEC) partially offload mobile edge server. Aiming cope packet error setting short communication (SPC) IIoT, consider standard automatic repeat request (ARQ) protocol two policies, i.e., either retransmitting an out-of-date (RO) or transmitting freshest (TF), when occurs. We derive closed form average AoI under these respectively, then formulate minimization problem by jointly optimizing blocklength MEC offloading ratio. Due nonconvexity nature problem, tackle it employing block coordinate descent (BCD) successive convex approximation (SCA) methods prove their convergence. Our extensive numerical results show that optimal yielded our proposed approach is almost identical from high-complexity exhaustive search method, has significant improvement over benchmark methods. From perspective, revealed strategy tends all server capacity local device less than threshold. Furthermore, found RO policy suitable for relatively small bandwidth large capability scenario, whilst TF better case.