Several studies have highlighted that the IEEE 802.15.4 standard presents a number of limitations such as low reliability, unbounded packet delays and no protection against interference/fading, that prevent its adoption in applications with stringent requirements in terms of reliability and latency. Recently, the IEEE has released the 802.15.4e amendment that introduces a number of enhancements/modifications to the MAC layer of the original standard in order to overcome such limitations. In this paper we provide a clear and structured overview of all the new 802.15.4e mechanisms. After a general introduction to the 802.15.4e standard, we describe the details of the main 802.15.4e MAC behavior modes, namely  Time Slotted Channel Hopping  (TSCH),  Deterministic and Synchronous Multi-channel Extension  (DSME) ,  and  Low Latency Deterministic Network  (LLDN). For each of them, we provide a detailed description and highlight the main features and possible application domains. Also, we survey the current literature and summarize open research issues.
['Domenico De Guglielmo', 'Simone Brienza', 'Giuseppe Anastasi']
IEEE 802.15.4e: A survey