Terahertz communication is emerging as a future technology to support Terabits per second link with highlighting features as high throughput and negligible latency. However, the unique features of the Terahertz band such as high path loss, scattering and reflection pose new challenges and results in short communication distance. The antenna directionality, in turn, is required to enhance the communication distance and to overcome the high path loss. However, these features in combine negate the use of traditional medium access protocols (MAC). Therefore, novel MAC protocol designs are required to fully exploit their potential benefits including efficient channel access, control message exchange, link establishment, mobility management, and line-of-sight blockage mitigation. An in-depth survey of Terahertz MAC protocols is presented in this paper. The paper highlights the key features of the Terahertz band which should be considered while designing an efficient Terahertz MAC protocol, and the decisions which if taken at Terahertz MAC layer can enhance the network performance. Different Terahertz applications at macro and nano scales are highlighted with design requirements for their MAC protocols. The MAC protocol design issues and considerations are highlighted. Further, the existing MAC protocols are also classified based on network topology, channel access mechanisms, and link establishment strategies as Transmitter and Receiver initiated communication. The open challenges and future research directions on Terahertz MAC protocols are also highlighted.

(1) Background: Childhood obesity is one of the greatest challenges facing public health in the 21st century. Currently, there is a great deal of interest in the concept of physical literacy due to its comprehensive nature on the development of physical activity. Physical literacy can be described as the motivation, confidence, physical competence, knowledge and understanding to value and take responsibility for engagement in physical activities for life. The aim of this paper is to provide a systematic review of the literature examining the relationship between physical literacy and risk of obesity in children. This paper also focuses on providing an evaluation of the availability and effectiveness of current physical literacy assessment tools. (2) Methods: This review was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. (3) Results: A total of 3267 papers were identified from five major databases. Twelve studies met the inclusion criteria, with nine studies included in the final review following quality appraisal. (4) Conclusions: This review identified significant gaps in our understanding of physical literacy emphasising the need for a consistent framework, standardised assessment tools and more experimental research.

The book, A Comprehensive Guide to 5G Security (Abro, A.B. et al; 2018), discusses the key security areas of 5G systems. This book is selected to review in this column because particular emphasis is given to the planning of threat mitigation from the perspective of telecom vendors and mobile network operators. In total, there are 17 chapters in this book which are categorized into four parts: 5G security overview; 5G netwowrk security; 5G cloud computing; and virtual network security. The weak point of the book is that it does not cover the layered aspects of 5G networks in detail, including the physical, MAC and network layers. The metadata available on the publisher’s website shows 474 pages; however, the hardcopy has 440 pages. Overall, after reading the book, it is clear that security and privacy are of utmost importance for new 5G technologies and networks, and this book can be a good read for covering the background and technological aspects for 5G networks and their security and privacy issues.