  Many use cases in the Internet of Things (IoT) will require or benefit from
location information, making positioning a vital dimension of the IoT. The 3rd
Generation Partnership Project (3GPP) has dedicated a significant effort during
its Release 14 to enhance positioning support for its IoT technologies to
further improve the 3GPP-based IoT eco-system. In this article, we identify the
design challenges of positioning support in Long-Term Evolution Machine Type
Communication (LTE-M) and Narrowband IoT (NB-IoT), and overview the 3GPP's work
in enhancing the positioning support for LTE-M and NB-IoT. We focus on Observed
Time Difference of Arrival (OTDOA), which is a downlink based positioning
method. We provide an overview of the OTDOA architecture and protocols,
summarize the designs of OTDOA positioning reference signals, and present
simulation results to illustrate the positioning performance.
