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.