JASC: Journal of Applied Science and Computations ISSN NO: 1076-5131 A Review of Smart Home Community in IoT Environment: Architectural survey and Challenges Ms. Libi Kurian#1, Ms.S. Dhanalakshmi*2 # * Department of Computer Science, Christ Nagar College, Trivandrum, Kerala, India PG and Research Department of MCA, Vivekanandha College of Arts& Science for Women, Erode, Tamilnadu, India. 1libi.kurian@yahoo.com Abstract— Smart cities aim to improve the citizens quality of life by exploiting information about city scale procedures extracted from heterogeneous data sources gathered on city wide distribution. The IoT is the empowering influence of smart city technologies at urban scale. IoT includes various elements like communication networks, communication protocols, sensing technologies, computations, analysis and services. The primary commitment of this survey paper is that it abridges the present condition of specialty of IoT architecture in smart city. Architecture specific study does always pave the structure of related field. In addition, most of the possible IoT technologies for smart city are introduced. Emerging IoT technologies were discussed by this survey and its challenges. Keywords— Smart City, Internet of things (IoT), Smart building, Security, IoT Architecture, smart city architecture, IoT technologies, challenges I. INTRODUCTION The web transformation has prompted the interconnection among individuals and PCs at an unremarkable scale and pace. The next revolution will be the interconnection between objects and appliances to create a shrewd environment. Currently it is estimated that there are 9 billion interconnected devices and in future it is highly expected to reach 24 billion devices by 2020 [9]. According to the recent market analysis report by Knud Lasse Lueth, IoT Analytics clearly indicates that Smart Cities and Smart Home stand out as the most prominent IoT applications in near future [1]. The smart city is becoming smarter than in the past as a result of the current expansion of digital technologies there has been a remarkable growth of digital devices, such as sensors, actuators, smartphones and smart appliances, because it is possible to interconnect all devices and speak with between through the Internet. This led to the huge marketable objectives of the Internet of Things (IoT) [8]. With the rapid rise of the population density inside urban areas, gathering information for day-to-day management of activities and long-term development planning in the city is essential in order to supply the requirements of the citizens. For example, take the case of a public transport system, some information such as real-time location and utilization, occupancy of parking spaces, traffic jams, and other data like weather conditions, air and noise pollution status, energy consumption, etc. should be gathered continuously [8]. These data will be analysed by using analytical tools and gives information to that particular city authorities that helps them to take precaution or necessary steps to solve it. Smart citizens, smart energy, smart buildings, smart mobility, smart technology, smart healthcare, smart infrastructure, smart governance and education and finally smart security are the key parts of shrewd urban communities [8]. II. ARCHITECTURAL DESIGN OF IOT An IOT architecture is a system of integration of numerous elements, several technologies and communication solutions. Sensors, protocols, actuators, cloud service, storage and computing tools for data analytics and presentation are considered to be the essential elements of IOT. There are identification and tracking technologies, wired and wireless sensor and actuator networks, enhanced communication protocols, and distributed intelligence for smart objects are just some of the most relevant [3] The IOT general architecture provide the media to be everywhere incorporating a large number of different and heterogeneous end systems and sensors to provide services that seamlessly employ very complex tasks [1]. Many IOT architectures depends on various applications. Different technologies have been applied to address the specific features of each applications of IOT [2]. Many and different architectures have been proposed by researchers. Basically, there are three IoT architecture layers [4]: 1. Perception Layer/ IoT Device Layer- The client side. 2. Network Layer/ IoT Getaway Layer -Operators on the server side. Volume VI, Issue VI, JUNE/2019 Page No:2147 JASC: Journal of Applied Science and Computations ISSN NO: 1076-5131 3. Application Layer/ IoT Platform Layer- A pathway for connecting clients and operators. The aim of the first layer is to identify each thing in IoT. It is collecting information through RFID tags, sensors, actuators and edge devices that interact with the environment. The second layer is the core of the internet of things. Discovers, connects and translates devices over a network and in a joint effort with the application layer. It sends the information which gathered through the perception layer. The third layer is preferred for the IoT social needs and industrial technologies [6]. Data processing and storage with specialized services and functionality for users. Figure 1 shows the 3-layer architecture [5] Fig 1 In fact, tending to the requirements of every one of these layers is significant on every one of the phases of IoT architecture. The key highlights of practical IoT architecture include functionality, scalability, availability, and maintainability. Due to enhancement in IoT, the 3-layer architecture cannot fulfil all the requirements of applications. Therefore, all the above-mentioned requirements are addressed in 4 stages of IoT architecture. In 4-layered architecture [7], the three layers Perception, Network and Application have the same functionality as that of the 3-Layer architecture. In 4-Layer architecture, information is sent to a support layer that is obtained from a perception layer. The support layer has two responsibilities. It confirms that information is sent by the authentic users and protected from threats. The second responsibility of the support layer is sending information to the network layer. The medium to transmit information from the support layer to network layer can be wireless and wire based. [7]. Due to a challenge in IoT regarding security and privacy the researchers proposed a 5-Layer architecture to make the IoT secure. The 5-Layer IoT Architecture essentially builds upon the 3-Layer approach. It has two more layers. The names of these newly proposed layers are Processing layer and Business layer. The top-level Business Layer highlights the various management, business logic, and top-level requirements that is able to provide consistent value to the business and end users. The user’s privacy is also managed by this layer. It also has the ability to determine how information can be created, stored and changed [7]. The processing layer is also known as a middleware layer. It collects the information that is sent from a transport layer. It performs processing onto the collected information. It has the responsibility to eliminate extra information that has no meaning and extracts the useful information. It is considered that a recently proposed architecture can fulfil the requirements of IoT regarding security and privacy [7]. Figure 2 presents the 4-layered and 5-layerd architecture. Volume VI, Issue VI, JUNE/2019 Page No:2148 JASC: Journal of Applied Science and Computations ISSN NO: 1076-5131 Fig 2 III. BASICS OF IOT ARCHITECTURE In an article [5] the author explains about the very basic requirements needed to implement a complete IoT architecture design. A. Concurrent Data Collection – support for collection, analysis and control from a large number of sensors or actuators. B. Efficient Data Handling – minimize raw data and maximize actionable information. C. Connectivity and Communications – provide network connectivity and flexible, robust protocols support between sensors/actuators and the cloud. D. Scalable – scale individual elements in the system using the same architecture. E. Security – end to end encryption and monitoring. F. Availability and Quality of Service – minimal latencies and fault tolerant. G. Modular, Flexible and Platform-independent – each layer should allow for features, hardware or cloud infrastructure to be sourced from different suppliers. H. Open Standards and Interoperable – communication between the layers should be based on open standards to ensure interoperability. I. Device Management – enable automated/remote device management and updates. J. Defined APIs – each layer should have defined APIs that allow for easy integration with existing applications and integration with other IoT solutions. IV. IOT TECHNOLOGIES FOR SMART CITY All paragraphs must be indented. All paragraphs must be justified, i.e. both left-justified and right-justified. A. RFID A Radio-Frequency Identification (RFID) system uses tags, or labels attached to the objects to be identified. They help in the automatic identification of anything they are attached to acting as an electronic barcode [9]. Two-way radio transmitterreceivers called interrogators or readers send a signal to the tag and read its response. The readers generally transmit their observations to a computer system running RFID software or RFID middleware [13]. An active tag has an on-board battery and periodically transmits its ID signal. A passive RFID are not battery powered and use the power of the readers interrogation signal to communicate the ID to the RFID reader. There are many applications of IoT in which RFID technology is used, such as a healthcare system, human tracking application and a gesture recognition system [7]. B. WSN A Wireless sensor network (WSN) consists of wireless sensor nodes which include a radio interface, an analog- to-digital converter (ADC), multiple sensors, memory and a power supply [8]. According to the wireless sensor node framework, it includes various kinds of intelligent sensors, enabling the collection, processing, analysis and dissemination of valuable information, gathered in a variety of environments. Sensor data are shared among sensor nodes and sent to a distributed or centralized system for analytics [9]. WSNs could be coordinated with RFID frameworks to obtain few objectives such as acquiring data in regards to the position of people and objects, development, temperature, movements etc. [8]. Volume VI, Issue VI, JUNE/2019 Page No:2149 JASC: Journal of Applied Science and Computations ISSN NO: 1076-5131 C. Addressing Schemes IoT creates an interconnection of things and stuff, for providing smart environments. For this purpose, it is essential to identify devices exclusively for the success of IoT. Exclusively addressing the large-scale mixture of things is very important to control them through the Internet. The critical features of creating a unique addressing structure are uniqueness, reliability, persistence and scalability. Every element that is connected and those that are going to be connected must be identified by their unique identification, location and functionalities [9]. D. NFC Near Field Communication (NFC) consists of communication protocols used for bidirectional short distance communication of electronic devices, typically a smart mobile device and a standard device. It is a set of short-range wireless technologies, usually involves a distance of 10 centimetre or less range. The application of NFC in smartphones enables us to use it as our personal cards such as bank card, identification card, public transportation card, access control cards [8]. E. Middleware Due to few concerns in regards to the heterogeneity of contributing things, to the restricted stockpiling and processability, alongside to the huge kinds of utilization, the middleware has a crucial undertaking in the interconnection of devices to the applications layer. The fundamental focus of the middleware is to briefly total the usefulness and correspondence capacities of all included devices. F. 3G and 4G LTE 3G, 4G and Long-Term Evolution (LTE) are guidelines for remote broadband correspondence for cell phones and data terminals based on the GSM/EDGE technologies. It utilizes packet exchanging and message exchanging. This technology is for broadband connectivity and was not intended for short range uses. They are most adaptable for Internet of Things. It supports IPV4 and IPV6, while for the 3G network the IPV4 supports and for 4G network the IPV6 satisfies the support requirements. G. EnOcean The EnOcean innovation is an energy harvesting wireless technology used primarily in building automation systems; but on the other hand, it is also connected to different applications in industry, transportation, logistics and smart homes. Modules based on EnOcean technology combine micro energy converters with ultra-low power gadgets and empower wireless communications between battery less wireless sensors, switches, controllers and gateways [13]. H. Bluetooth Bluetooth is a wireless technology standard for exchanging data over short distances using short-wavelength radio waves from 2.400 to 2.485 GHz in the ISM band from fixed and mobile devices, creating personal area networks (PANs) with high levels of security. I. Dash 7 DASH7 Alliance Protocol (D7A) is an open source Wireless Sensor and Actuator Network protocol, which operates in the 433 MHz, 868 MHz and 915 MHz unlicensed ISM band/SRD band. DASH7 gives multi-year battery life, scope of up to 2 km, low latency for associating with moving things. It is worth seeing that Dash is alluring in military application particularly substation development. Some of its applications are perilous material checking, manufacturing and warehouse optimizations and smart meter development [8]. V. SMART CITY ARCHITECTURE When we look into the recent studies and developments of smart city architecture, we can find that there is no particular standardization in building a smart city. The overall purpose of a smart city is to achieve efficient management in all segments of the city while at the same time satisfying the needs of its citizen. It must also be aligned with the principles of justifiable development and considering the technological modernization and a collaboration between economic and social agents as the main driving forces of change. In the paper,” Study of the Architecture of a Smart City” [10] the author identifies two type of architecture in a smart city. An External architecture that monitors the exterior of the city such as streets, parks, avenues, leisure areas, parking space etc. Here it is necessary to place a series of sensors that allow to obtain a series of information for making decision either in public light or in other elements of the city such as bus shelters, garbage bins, street light post etc. The most architectural infrastructure can be used are the star architecture or mesh network. The second type is an Internal architecture that monitors the interiors of the buildings, flow of humans and things, air conditioning, water etc. The placement of sensors inside a building has great dependence on certain parameters such as geometric shop, type of building, if its heritage or not, usability, private or public Volume VI, Issue VI, JUNE/2019 Page No:2150 JASC: Journal of Applied Science and Computations ISSN NO: 1076-5131 ownership etc [10]. There is a great need for the correct placement of sensors and actuators for the proper function of the IoT systems. Figure 2 shows a representation of a smart city architecture. Fig 2: Schematic diagram of a smart city architecture (Image courtesy of ARC Advisory group) VI. EMERGING IOT TECHNOLOGY CHALLENGES The innovations and standards of IoT will have an exceptionally wide impact on organizations, influencing business strategy, risk management and a wide range of technical territories, such as architecture and network design. Some emerging IoT technology challenges are [14]: A. IoT Security Security technologies will be required to shield IoT gadgets and platforms from both information attacks and physical altering, to encrypt their communications, and to address new encounters such as impersonating "things" or denial-of-sleep attacks that drain batteries. IoT security will be complicated by the fact that many "things" use simple processors and operating systems that may not bolster sophisticated security approaches. B. IoT Analytics IoT business models will misuse the data gathered by "things" in many ways, which will demand new analytic tools and algorithms. As information volumes increase throughout the next five years, the requirements of the IoT may diverge further from traditional analytics. C. IoT Device (Thing) Management Seemingly perpetual nontrivial "things" will require management and observing, including device monitoring, firmware and software updates, diagnostics, crash analysis and reporting, physical and security management. Tools must be capable of managing and monitoring thousands and perhaps even millions of devices. D. Low-Power, Short-Range IoT Networks Low-power, short-range networks will govern wireless IoT connectivity through 2025, far outnumbering connections using wide-area IoT networks. However, commercial and technical trade-offs mean that many solutions will coexist, with no single overwhelming winner. Volume VI, Issue VI, JUNE/2019 Page No:2151 JASC: Journal of Applied Science and Computations ISSN NO: 1076-5131 E. Low-Power, Wide-Area Networks Traditional cellular networks don't deliver a good blend of technical features and operational expense for those IoT applications that need wide-area coverage joined with relatively low bandwidth, good battery life, low hardware and operating cost, and high connection density. Emerging standards such as narrowband IoT will probably overwhelm this space. F. IoT Processors The processors and architectures used by IoT devices define many of their capabilities, for example, regardless of whether they are capable of strong security and encryption, power consumption, sophisticated enough to support an operating system, updatable firmware, and embedded device management agents. Understanding the ramifications of processor decisions will demand deep technical skills. G. IoT Operating Systems Traditional operating systems such as Windows and iOS were not designed for IoT applications as they consume more power, need fast processors, and in some case lack guaranteed real-time response. Support large memory and so for small devices it may not support the chips that IoT developers use. There is a need for IoT-specific operating systems that suit many different hardware footprints and feature needs. H. IoT Platforms IoT platforms pack many of the infrastructure components of an IoT system into a single product. The services provided by such platforms are Low-level device control and operations, device monitoring and management, security, and firmware updates; IoT data acquisition, transformation and management; IoT application development, including event-driven logic, visualization, analytics and connectors to link to enterprise systems I. IoT Standards and Ecosystems Standards and their associated application programming interfaces (APIs) will be essential because IoT devices will need to interoperate and communicate. Many IoT ecosystems will emerge, and organizations creating products may have to develop alternatives to support multiple standards and to update products as the standards evolve and new standards and APIs emerge. VII. CONCLUSION The aim of this review article is to explain the IoT concepts used in smart city, in a comprehensive manner. The article also explores the variant specifications and features of IoT architectural designs with the importance of specifying the very basic requirements needed to implement a complete IoT architecture design. Various IoT technologies for smart city are elaborated. IoT faces a lot of challenges due to constrained devices. The emerging IoT technology challenges arising from implementing IoT systems were outlined. 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