  In various Internet-of-Things (IoT) applications, a number of devices and
sensors are used to collect data sets. As devices become more capable and
smarter, they can not only collect data sets, but also process them locally.
However, since most devices would be limited in terms of computing power and
energy, they can take advantage of offloading so that their tasks can be
carried out at mobile edge computing (MEC) servers. In this paper, we discuss
computation offloading for devices in IoT applications. In particular, we
consider users or devices with sporadic tasks, where optimizing resource
allocation between offloading devices and coordinating for multiuser offloading
becomes inefficient. Thus, we propose a two-stage offloading approach that is
friendly to devices with sporadic tasks as it employs multichannel random
access for offloading requests with low signaling overhead. The stability of
the two-stage offloading approach is considered with methods to stabilize the
system. We also analyze the latency outage probability as a performance index
from a device perspective.
