Comprehensive Survey on Smart Cities Architectures and Protocols 1 Comprehensive Survey on Smart Cities Architectures and Protocols Syed Waqar Shah1,, Tahira Magsi1, and Ahthasham Sajid1,* 1Department of Computer Science, Faculty of ICT, Balochistan University of Information Technology Engineering and Management Sciences, Quetta, Baluchistan, Pakistan Abstract The world has advanced more than two centuries in the last 20 years in every aspect of existence. Every day, new inventions are made that improve our quality of life and make our lives easier. One aspect of contemporary innovation is the idea of the smart city. Many businesses and governments are embracing the idea of the "smart city" to improve quality of life for citizens while cutting costs. This model is made up of a variety of different technologies. I nternet of Things, cloud and fog computing, UAV, and other technologies are among them. On the other hand, in order to achieve these important goals, it is necessary to provide the multiple system components with the necessary synchronisation and mechanism, which calls for well-organized interaction and communication protocols. In this study, we categorise the networking requirements and characteristics of smart. Keywords: IoT, Cloud Computing, UAV. Received on 19 June 2022, accepted on 05 September 2022, published on 07 September 2022 Copyright © 2022 Syed Waqar Shah et al., licensed to EAI. This is an open access article distributed under the terms of the CC BY- NC-SA 4.0, which permits copying, redistributing, remixing, transformation, and building upon the material in any medium so long as the original work is properly cited. doi: 10.4108/eetsc.v6i18.2065 * Corresponding author. Email: ahthasham.sajid@buitms.edu.pk 1. Introduction The Smart Cities concept brings revolution to urban planning. In 1994 Amsterdam formed a virtual digital city to endorse internet procedures [3]. They are the result of knowledge-intensive and ground-breaking policies, pointing at refining sensible enactment of cities [4]. Smart cities are based on an auspicious combination of human capital, and commercial capital [4].The smart cities concept is a superlative typical urban gathering, but in actuality, we note numerous smart appearances in urban systems, such as creative districts, smart urban villages, or sustainable knowledge-based urban spaces [4]. The contextual idea of smart cities is built on the circumstance that cities house, in principle, a variety of inventive talents and can offer novel and justifiable solutions [1]. The accumulation compensations generated in modern urban groups are critical limitations for developing the potential benefits of innovative urban spaces. It has been projected that by almost 2050, two-thirds of the world's inhabitants will be living in urban regions, which will be around 7billion people. Hence, equipping the cities with smart technologies and analytics can make it resilient and efficient. A large number of cities like Dubai, Singapore, Amsterdam, New York etc., around the globe start using the Smart City concept to facilitate their citizens using city infrastructure. These smart services help to improve the working techniques of different departments e.g. Education, Transportation, Healthcare, and many others. The Smart City concept is based on many advanced technologies like I.O.T, Wireless Sensor Networks (WSN), Robotics, Unmanned Ariel Vehicles (UAV), Cyber-Physical Systems (CPS), Big data analytics, etc. [5]. A major step toward the practical understanding of the Smart City concept comprises the growth of a communication setup capable of gathering data from a large diversity of unlike devices in a typically constant and seamless manner, according to the Internet of Things (IoT) paradigm [2]. The Internet of Things (IoT) period is progressing into a sensor-initiated, actuation-driven, and EAI Endorsed Transactions on Smart Cities Research Article EAI Endorsed Transactions on Smart Cities 03 2022 - 09 2022 | Volume 6 | Issue 18 | e5 https://creativecommons.org/licenses/by-nc-sa/4.0/ https://creativecommons.org/licenses/by-nc-sa/4.0/ mailto:ahthasham.sajid@buitms.edu.pk https://www.sciencedirect.com/topics/computer-science/internet-of-things Syed Waqar Shah, Tahira Magsi, and Ahthasham Sajid 2 machine intelligence-based decision-making platform for smart cities [3]. The smart environment is sedate by the attraction of the natural environment, pollution intensities, environmental safety activities, and resource supervision methods. It is assumed that cities can be well-defined as smart if they have the following elements as described in figure 1 below [13]. Figure 1. Elements of Smart City 2. Characteristics of Smart City As there is no predefined description of a smart city but a handful of researchers have jotted down a few characteristics which sum up the modern city. A digital city comprises all the expected virtues one looks forward to in a modern city. A city must be inclusive of its entire people who are liveable and appreciate the innovation of technology. The city is resilient and resource efficient. As per the economic point of view, it will be dynamic (adaptable to change) and sustainable. But it must care for the environment and be climate-friendly. The natural ecosystem is in complete harmony with such a resilient city [19]. While the tool used to achieve the Holy Grail is embedding the Information and Communication Technology (ICT) in the nerve of the city through huge financial expenditure. The assistance of data-driven information with a participatory approach paves a path for integrating planning. Figure 2 [12] demonstrates the characteristics and Tools which can help in transform a city into a smart city. Figure 2. Characteristics and Tolls of Smart City [12] 3. Related Work The amount of work issued concerning about network and communication issues of the digital city is meagre. Zanella et al [6] cursory define the ways through which IoTs can be deployed in Padova, Italy. Zanella offered a two-way approach to address the data access, i.e. (i) using unlicensed short-range communication using a multi-hop mesh network (ii) Using licensed long-range cellular technology [7]. Laccase et al. suggested utilizing Raspberry-Pi Card to control the street lights through the ZigBee sensor network and Wi-Max [8]. While Wan et al. proposed event-based communication architecture that allows facilitating communication between Machine to Machine (M2M), as machine being the essential component of the modern city [9]. Quality of service is a vital part of any application to be successful. Jin et al in their research paper presented different architecture concepts based on Quality of Service (QoS) [10]. Information-Driven Architecture (IDRA) is an innovative network architecture that focused on network functions and services such as forwarding, naming, addressing, etc. [11]. These network services are mostly used for configuration purposes for different applications. The participatory sensing network architecture is well- thought-out a special case and a new model of IoT. In this model, citizens through their consumer devices gather, examine, and share sensor records. This can be entitled “human-as-a-sensor”. In this mode, wireless infrastructures such as Wi-Fi, GPRS, and 3G are used. Some conceivable applications of this architecture are ecological observing, intellectual carrying, and healthcare. QoS in such a network can be complicated as humans are the central foundation of data and humans can be slothful, privacy-stricken, and prone to errors. The smart economy is restrained by private enterprise and a city's output, alteration to changes, the suppleness of the labour market, and international collaboration [13]. Smart mobility is professed by the convenience of information and communication organization, from side to side the growth of supportable, ground-breaking, and harmless transport [13]. This is the body text with indent. This is the body text with indent. This is the body text with indent. This is the body text with indent. This is the body text with indent. This is the body text with indent. This is the body text with indent. This is the body text with indent. This is the body text with indent. This is the body text with indent. This is the body text with indent. 4. Architectures of Smart Cities There are many proposed models of architecture that are suggested by numerous authors but the two main which are quite adaptable are: 1. Centralized Operational Platform: This model is proposed by Mahmoud et al. He has suggested that a digital city must have a pyramid-shaped architecture. Smart City Smart Mobility Smart People Smart Environment Smart Living Smart Economy Smart Governance EAI Endorsed Transactions on Smart Cities 03 2022 - 09 2022 | Volume 6 | Issue 18 | e5 Comprehensive Survey on Smart Cities Architectures and Protocols 3 Where every management and operation is monitored through a centralized platform. At the bottom, of the pyramid, there lies a smart infrastructure that includes all the devices that are employed in this project. Following that in the middle tier, there lie smart database resources, smart building management, and smart infrastructure; which keep a record of all the data being generated. While at the top of the helm, lies the smart city itself which take care of all the affair of the city. Figure 3. Centralized Operational Platform 2. Three layer Architecture: Three-layer architecture was proposed by Harrison et al, whose crux is that a city will be divided into three halves for better management. According to this model, the Instrumented layer captures and integrates the live world data with the help of the sensors, like water reading meter or water quality measurement, etc. Then it’s the onus of the Interconnected Layer to act as the middleman and integrated the data collected and maps numerous outputs into some useful information. In the end, the intelligent layer processes the desired data into a broader context to identify city-related issues and analyze them to take action upon them. Figure 4. Three Layers Architecture 5. Networking Characteristics of Smart Cities 5.1 Bandwidth Bandwidth ranges from Low, Medium, and High (L, M, H) [15]. For example, if those applications which only control commands required a small bandwidth then those applications which utilized image and video data required Medium or High bandwidth. 5.2 Delay Tolerance Delay tolerance varies from application to application in smart city architecture. In some applications where immediate control is essential, a delay means disaster e.g. collision between cars While in some applications, such as UAVs required data for future dispensation. 5.3 Power Consumption Power consumption is a vital need for a smart city system. However, it is visible in table 1 [14] that those applications which have a local energy source, easily deal with high power consumption and those applications which have low energy capacities have low power consumption. 5.4 Reliability Reliability levels vary from one application to another. As shown in Table 1 [14] smart water networks have medium dependability necessities and smart grids and intellectual conveyance have a high-reliability ratio. 5.5 Security Security importance is the same as reliability. For example, some applications due to it critical data required high security and some applications required medium security level i.e. monitoring applications. 6. Routing Protocols of Smart Cities Smart city is an amalgamation of heterogeneous networks and technologies. So, every component that gets embedded in the digital city base has its own characteristics and requirement. Therefore, all relevant protocols are to be followed to take maximum utilization from that component. Wireless Technology: In the smart city if wireless technology is deployed then its only communication mode will be Wi-Fi, GPRS, or 3G networks. Short-range applications are designed where the required energy is limited and are compact in size. They Smart City Database Resource Smart Infrastructure Intelligent Layer Interconnected Layer Instrumented Layer EAI Endorsed Transactions on Smart Cities 03 2022 - 09 2022 | Volume 6 | Issue 18 | e5 Syed Waqar Shah, Tahira Magsi, and Ahthasham Sajid 4 don’t need frequent battery changes. Applications that are short-range and installed are in smart buildings; water and grid prefer IEEE 802.15.4 ZigBee protocol [20]. Table 1. Networking Protocols for Smart City Applications Protocol Data Range Transmis sion Range Applications Satellite 10 Mbps (for upload) 7 1 GBPS (downloads) Satellite can cover 100’s km to entire Earth UAV, monitoring UAV, Intelligent Transport Cellular 4G/ LTE 300 Mbps to1Gbps Normally 1 km area diameter Pipeline monitoring, Smart Grid, UAVs, smart water Cellular 3G 144 kbps (mobile) To 42 mbps (stationary) 1km to several stationery -do- WiMAX 802.16 2- 75mbps Up to 56km -do- 802.11n 15,30,45,60,9 0,120,135, 150 mbps 250m outdoors All 802.11g 6,9,12,18,24, 36,48,54mbp s 140m outdoors All 802.11b 1,2,5.5, 11mbps -do- All 802.11a 24,36,48,54 mbps 120m outdoors All Bluetooth 802.15.1 1mbps 10 to 100 m Smart water, Grid and building Zigbee 802.15.4 20kbps to 250kbps 10 to 20m Smart water, Grid and building Bluetooth uses IEEE 802.15.1 which serves as master/slave Time Division Duplex (TDD) protocol. It ranges from 10 to 100 m. (WiMAX), Cellular 3G, Cellular 4G/LGT, and Satellite use IEEE 802.11a, IEEE 802.11b, IEEE 802.11b, IEEE 802.11 g protocols respectively. These protocols are the most frequently used in all urban city systems. 3G and 4G are used in smart grid applications, water management, pipeline monitoring, and UAVs While satellite communication is employed for UAVs, pipeline monitoring and intelligent transport. Table 1 further describe the details of protocols with features. 7. Conclusion With each passing day, all technical platforms—including Cloud computing, the Internet of Things, wireless networks, robotics, etc.—have experienced a growth. The goal is to create a city that is smart and capable of coping with the constantly expanding population as well as their demands through the convergence of all these technologies. To provide the greatest utility with the least amount of overhead costs, every vista is being investigated. The core of smart technology relies entirely on reliable routes for communicating information. The only paradigm for turning a town or metropolis into an intelligent one is a quick and dependable transmission route. People do absolutely contribute to technology when they are connected to it directly through applications. Acknowledgements. We would like to thanks our teacher Dr. Ahthasham Sajid to motivate and guide us for the understanding and writing of a survey paper as class assignment during MS (CS) course. References [1] Ermacora G, Rosa S, Bona B (2015) Sliding autonomy in cloud robotics services for smart city applications. In: Proceedings of the Tenth Annual ACM/IEEE International Conference on Human-Robot Interaction Extended Abstracts. ACM. pp 155–156 [2] A. Cenedese, A. Zanella, L. Vangelista and M. 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