Computer Communications 88 (2016) 1-24 Contents lists available at ScienceDirect computer communications Computer Communications journal homepage: www.elsevier.com/locate/comcom ELSEVIER Review IEEE 802.15.4e: A survey CrossMark Domenico De Guglielmoa, Simone Brienzad*, Giuseppe Anastasia,b a Dept. of Information Engineering, University of Pisa, Italy b Smart Cities National Lab., CINI, Italy ARTIＣLE INFO ＡＢＳＴＲＡＣＴ Article history: Several studies have highlighted that the IEEE 802.15.4 standard presents a number of limitations such Received 25 January 2016 as low reliability, unbounded packet delays and no protection against interference/fading, that prevent Revised 3 May 2016 its adoption in applications with stringent requirements in terms of reliability and latency. Recently, the Accepted 9 May 2016 IEEE has released the 802.15.4e amendment that introduces a number of enhancements/modifications to Available online 13 May 2016 the MAc layer of the original standard in order to overcome such limitations. In this paper we provide Keywords: a clear and structured overview of all the new 802.15.4e mechanisms. After a general introduction to IEEE 802.15.4e the 802.15.4e standard, we describe the details of the main 802.15.4e MAC behavior modes, namely Time TSCH DSME Latency Deterministic Network (LLDN). For each of them, we provide a detailed description and highlight LLDN. the main features and possible application domains. Also, we survey the current literature and summarize WSANs open research issues. @ 2016 Elsevier B.V. All rights reserved. cost remote monitoring and control of the electric power system. 1. Introduction The real-time information gathered from WSANs can be analyzed Wireless sensor and actuator networks (WSANs) will play a key to diagnose problems early and serve as a basis for taking remedial role in the realization of the future Internet of Things (loT) [1- actions [7,8]. Energy eficiency is usually the main concern in the design of a putational system can interact with the physical world [4-5]. In WSAN. This is because sensor/actuator devices are typically pow- ered by batteries with a limited energy budget and their replace- a WSAN many sensor and actuator devices are placed in the same physical environment for monitoring and control operations. Phys- ment can be very expensive or even impossible [9]. However, in ical quantities, such as temperature, pressure and light intensity many application domains, additional requirements such as relia- are continuously measured by sensor devices. Then, the acquired bility, timeliness and scalability need to be considered as well [9- 11]. Reliability and timeliness are very critical issues for industrial data are sent to a central controller using wireless links. The con- troller analyzes the received information and, if needed, changes and healthcare applications. If data packets are not delivered to the the behavior of the physical environment through actuator devices. final destination, correctly and within a pre-defined deadline, the WSANs are already used in many application domains, ranging correct behavior of the system (e.g., the timely detection of a crit- from traditional environmental monitoring and location/tracking ical event) may be compromised. The maximum allowed latency applications to critical applications such as those in the industrial, depends on the specific application and ranges from tens of mil- smart grid and healthcare domain [6]. In the industrial field, WSAN liseconds (e.g., for discrete manufacturing and factory automation), applications include real-time monitoring of machinery health, fac- to seconds (e.g., for process control), and even minutes (e.g., for tory automation, distributed and process control, detection of liq- asset monitoring). Finally, scalability is fundamental as WSANs can uid/gas leakage, radiation check and so on. In the healthcare do- be composed of hundreds to thousands of nodes. main, WSANs are used for the monito