  Machine-type communication (MTC) is the key technology to support data
transfer among devices (sensors and actuators). Cellular communication
technologies are developed mainly for "human-type" communications, while
enabling MTC with cellular networks not only improves the connectivity,
accessibility, and availability of an MTC network but also has the potential to
further drive down the operation cost. However, cellular MTC poses some unique
challenges due to a huge mismatch between the cellular user equipment and the
MTC device, caused mainly by the physical limitations, deployment environment
and density, and application behavior of MTC devices. One of the most
challenging issues is to provide an efficient way for an MTC device to access
the network. We address the issues in the existing random access scheme in a
cellular system (e.g., LTE), and propose an effective spectrum concept enabling
a power and spectrally optimized design specifically-tailored for MTC.
