Communication technologies are developing very rapidly and achieving many breakthrough results. The advent of 5th generation mobile communication networks, the so-called 5G, has become one of the most exciting and challenging topics in the wireless study area. The power of 5G enables it to connect to hundreds of billions of devices with extreme-high throughput and extreme-low latency. The 5G realizing a true digital society where everything can be connected via the Internet, well known as the Internet of Things (IoT). IoT is a technology of technologies where humans, devices, software, solutions, and platforms can connect based on the Internet. The formation of IoT technology leads to the birth of a series of applications and solutions serving humanity, such as smart cities, smart agriculture, smart retail, intelligent transportation systems, and IoT ecosystems. Although IoT is considered a revolution in the evolution of the Internet, it still faces a series of challenges such as saving energy, security, performance, and QoS support. In this study, we provide a vision of the Internet of Things that will be the main force driving the comprehensive digital revolution in the future. The communication technologies in the IoT system are discussed comprehensively and in detail. Furthermore, we also indicated indepth challenges of existing common communication technologies in IoT systems and future research directions of IoT. We hope the results of this work can provide a vital guide for future studies on communication technologies for IoT in 5G.

<p class="0papersubtitle">In recent years, the Mobile Ad Hoc Network (MANET) has a vital role in many fields such as healthcare, military, rescue and smart city. Because of its mobility and ad hoc, each mobile network node acts as a router with limited battery energy. The out of energy network node not only affects its own ability to receive/receive packets but also affects the overall performance of the entire network. Therefore, designing an energy-efficient routing protocol will help to optimize the efficiency of MANET. Many routing protocols have been proposing to solve this problem. In this paper, we conducted a survey of the proposed energy-saving routing protocols in the last decade for MANET. Based on the survey results, we propose open research directions. We hope that this work will make a strong motivation in the field of energy-efficient routing research for MANET. The survey results are also a vital basis to serve the in-depth researches in the routing field for MANET of our research team.</p>