# MAC Layer Protocols for Internet of Things: A Survey
###### Abstract  
Due to the wide variety of uses and the diversity of features required to meet an application, Internet of Things (IoT) technologies are moving forward at a strong pace to meet this demand while at the same time trying to meet the time-to-market of these applications. The characteristics required by applications, such as coverage area, scalability, transmission data rate, and applicability, refer to the Physical and Medium Access Control (MAC) layer designs of protocols. This paper presents a deep study of medium access control (MAC) layer protocols that are used in IoT with a detailed description of such protocols grouped (by short and long distance coverage). For short range coverage protocols, the following are considered: Radio Frequency Identification (RFID), Near Field Communication (NFC), Bluetooth IEEE 802.15.4, Bluetooth Low Energy, IEEE 802.15.4, Wireless Highway Addressable Remote Transducer Protocol (Wireless-HART), Z-Wave, Weightless, and IEEE 802.11 a/b/g/n/ah. For the long range group, Narrow Band IoT (NB-IoT), Long Term Evolution (LTE) CAT-0, LTE CAT-M, LTE CAT-N, Long Range Protocol (LoRa), and SigFox protocols are studied. A comparative study is performed for each group of protocols in order to provide insights and a reference study for IoT applications, considering their characteristics, limitations, and behavior. Open research issues on the topic are also identified. Internet of Things; Low-Power Wide Area Network (LPWAN); Low-Rate Wireless Personal Area Networks (LR-WPANs); short range protocols; long range protocols; medium access control; MAC layer protocols; Layer two protocols +
Footnote †: journal: _Future Internet_  
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the development and deployment of each protocol. Therefore, the study of MAC layer protocols can show how to design a suitable technological solution for an application. Based on its own needs, IoT applications may require the adaptation of the existing network protocols so that they can meet the requirements of IoT applications. Protocols may need to be adjusted, evolved or developed to meet the IoT applications that demand different performance characteristics such as far-reaching, reliable and robust low power transmission techniques. According to requirements, it is possible to classify and point out the main MAC layer protocols suitable to attend a service characteristic. The already existing definitions such as Wireless Body Area Networks (WBAN), Wireless Personal Area Networks (WPAN), Low Rate Wireless Personal Area Networks (LR-WPAN), and Wireless Local Area Networks (WLAN) can be classified as short distance protocols due to their maximum range of 1 km. While Wide Area Networks (WAN) and Low Power Wide Area Networks (LP-WAN) protocols can be used as references for long range classification due their ranges of more than 1 km. WAN protocols are commonly designed for user content and the media. Some of their evolution such as Long Term Evolution (LTE) CAT-M have enhancements to support some IoT requirements such as lower power consumption. LP-WAN protocols came to attend long range with low power consumption but enough data rate to attend IoT services requirements. The purpose of this paper is to present a deep study of short and long distance MAC layer protocols used by IoT solutions, addressing the MAC layer characteristics that defines each protocol behavior and applicability. This approach arises MAC layer comparisons in several aspects, including distance coverage, transmission data rate, transmission efficiency, communication mechanisms, MAC and PHY (Physical) layer control techniques, both in terms of use of resources and efficiency aspects of packet processing among other performance metrics. This study also gives inputs to obtain reference and comparison parameters in the design or choice of a technology to better serve a certain application, with specific characteristics.