# Internet of Things and Its Applications: A Comprehensive Survey
## 1 Introduction  
With an extensive growth in demand for a higher throughput, larger capacity, and lower latency for users, the 5G network is greatly expected to fulfill the desired requirements [1]. The throughput is expected to be very high, the energy consumption will be significantly lower, and the end-to-end will be reduced to less than 1 ms, which all comply with the International Mobile Telecommunications (IMT) standard for the beyond 5G wireless networks [2]. To achieve this milestone, research and industrial communities have both suggested that future wireless systems will take advantage of the numerous emerging technologies, such as the Millimeter-Wave (mm-wave)frequency band [3; 4]; Cognitive Radio (CR) [5]; Massive-Multiple Input Multiple Output (M-MIMO) [6]; Cooperative Networks (CR) using Relay Nodes (RNs) [7]; Coordinated Multipoint Operation (CoMP) [8]; Wireless Sensor Networks (WSN) [9]; Mobile Ad Hoc Networks (MANETs) [10; 11]; Device-to-Device (D2D) communication [12; 13]; Internet of Things (IoT) [14; 15]; Ethernet Passive Optical Networks (EPON) [16]; Heterogeneous Networks (HetNet) [17]; and cellular cloud computing, including big data [18]. Moreover, the use of various power optimizations [19], handover processes [20], interference cancellation [21], data security management [22], routing protocols [23], and scheduling algorithms [24] with optimal enhancement can also deliver ultimate results. New approaches, such as satellite communication in the mmWave spectrum [25], Artificial Intelligence [26], machine learning-based communication [27; 28], blockchain [29], and human-centric communication [30], are promising ideas for designing efficient base stations in future networks [31; 32]. The next-generation networks will provide ubiquitous internet and cellular services to cater to the more than fifty billion devices forecasted to be internet-enabled, including the human-type and machine-type communication systems [33]. Indeed, being able to provide wireless services to such an unprecedented number of smart nodes will be the aim of the next generations of wireless networks [34].  
The term IoT has been considered as an expanding technique applied in various applications and functions, from smart environments and houses to personal healthcare and others [35]. It is described as a smart concept for the internet relating everything to the Internet and data organization and information exchange [36]. Large-scale IoT intelligent systems have become more efficient and effective by using the properties of \"symmetry\" and \"asymmetry\". This can help in a range of IoT applications, for example, in water quality analytics, bee colony status monitoring, accurate agriculture, data communication balancing, smart traffic management, spatiotemporal predicting, and intelligent engineering. Several studies are currently working on IoT technologies to sustain their necessity in platforms developing technology [37]. Although there are diverse definitions and explanations for understanding IoT, it has a subsequent edge associated with the assimilation of the physical world with the virtual one of the internet [38]. The paradigm of IoT is simplified as _any-time, any-place, and any-one_ connected [39]. The implementation of this technology makes things and people closer and everyday life easier [40]. The purpose of IoT is to ensure a connection between devices, where each provides information and data. These devices are generally personal objects that are frequently carried, including smartphones, vehicles, healthcare devices, and office connected devices [41]. Moreover, Radio-Frequency Identification (RFID) is considered to be one of the first applications that saw the light and has played a crucial role in numerous technologies, such as sensors, smart objects, and actuators [42]. However, Machine-to-Machine communication (M2M) [43] and Vehicle-to-Vehicle communication (V2V) [44] represent the actual applications showing the significant advantages of IoT [45; 46].