IoT in Smart Urban Planning: A Comprehensive Review of Applications, Developments, and Engineering Perspectives

The rapid evolution of urbanization necessitates the deployment of smart technologies to create sustainable, efficient, and resilient cities. This paper presents a comprehensive review of the role of Internet of Things (IoT) technologies in enabling smart urban environments, with a focus on practical applications, investment trends, and electronics engineering contributions. The review covers real-world IoT use cases across key urban domains mobility, energy, environment, infrastructure, and governance supported by insights into recent global developments (2022-2024). It also analyzes smart city investment patterns, highlighting the growth of IoT-driven infrastructure and service models. From a technical perspective, the paper examines common urban IoT sensors (e.g., air quality, water, noise, and motion), their performance metrics, power profiles ( $\mu $ W to mW), and communication technologies (LoRaWAN, BLE, Wi-Fi, Zigbee). Comparative evaluations emphasize trade-offs between accuracy, energy efficiency, and range. Challenges related to power management, network scalability, cybersecurity, and sustainability are discussed, along with future research directions including tinyML, 6G networks, and biodegradable sensor platforms. The findings reinforce that electronics engineers play a pivotal role in designing and securing next-generation smart city systems by integrating innovation with ecological responsibility.