LTE-M Evolution Towards 5G Massive MTC

Massive machine type communication (mMTC) has been identified as an important use case for 5G New Radio wireless technology. In 4G Long-Term Evolution (LTE), 3GPP has previously introduced LTE-M for low-power, wide-area networks supporting the Internet of Things. Rel-13 specifications for LTE-M were completed in 2016. Rel-14 enhancements were completed in 2017 while Rel-15 enhancements are ongoing and expected to be completed in 2018. In this paper, we provide an overview of LTE-M and describe its evolution in subsequent releases. The features of the technology that have specifically been designed for mMTC are discussed. In addition, we present evaluations of LTE-M against 5G performance targets and show that mMTC requirements can be satisfied by LTE-M. To meet the 5G mMTC requirements, 3-dB power spectral density boosting is used in the downlink. In addition, for some requirements, 4 receive antennas at the eNB are required instead of the more typical 2 receive antennas. Thus, LTE-M will comprise an important component of 5G New Radio technology.