  Machine-to-machine (M2M) communications are expected to provide ubiquitous
connectivity between machines without the need of human intervention. To
support such a large number of autonomous devices, the M2M system architecture
needs to be extremely power and spectrally efficient. This article thus briefly
reviews the features of M2M services in the third generation (3G) long-term
evolution and its advancement (LTE-Advanced) networks. Architectural
enhancements are then presented for supporting M2M services in LTE-Advanced
cellular networks. To increase spectral efficiency, the same spectrum is
expected to be utilized for human-to-human (H2H) communications as well as M2M
communications. We therefore present various radio resource allocation schemes
and quantify their utility in LTE-Advanced cellular networks. System-level
simulation results are provided to validate the performance effectiveness of
M2M communications in LTE-Advanced cellular networks.
