# Building Fire Evacuation: An IoT-Aided Perspective in the 5G Era
## 1 Introduction
It requires reliable information on the building plan, fire information, and occupants' locations to help plan the evacuation strategy. It needs effective means of communication to guide the occupants during the evacuation. Therefore, it is difficult to organize a safe and effective total building evacuation in tall buildings at current stages. The delayed evacuation in the Grenfell Tower fire indicates that building fire evacuation still faces some common difficulties and challenges. The major deficiencies include inadequate situational awareness of interior fire environments, less effective communication between occupants and rescuers, and a lack of systematic analyses of evacuation strategies. If these insufficiencies cannot be addressed, the tragedy of the Grenfell Tower fire is likely to happen again. To successfully overcome these insufficiencies, we must have innovative approaches and new technologies for managing the facilities, such as effective detection, monitoring, tracking system, data analytics, communication systems, etc., to provide valuable support for developing an innovative building fire evacuation system. The 21 st century is undergoing a fast-paced trend of digitalization with the emergence of the Internet of Things (IoT). The IoT is an integration of technologies that connects ubiquitous devices and facilities with various networks to provide efficient and secure services for all applications anytime and anywhere [5]. By facilitating the collection and exchange of data among virtually everyone and everything, the IoT is enabling the cyber and physical environments to become unprecedentedly entangled, which promotes efficiency in performance and economic benefits and minimizes the need for human involvement. At present, tall building fire evacuation insufficiencies come from the inadequate perception of fire-ground information and the lack of effective communication means between the interior and exterior of the incident premise. These insufficiencies eventually cause inappropriate decisions in evacuations. The use of IoT can provide a possible solution for building evacuation control in fire emergencies. By using the IoT to build a connection with a wide variety of sensors, actuators, and devices pre-installed or post-deployed on the fire-ground, the IC and fire control room can obtain fire-ground information in real-time. Moreover, embracing the strong analytical power of IoT to analyze a huge volume of data generated from various connected IoT sensors and devices, the IoT system can tell more available information to help ICs make more appropriate decisions during the commanding. Another factor that makes the IoT a welcome solution for building fire evacuation control is the incentive of the fifth generation of cellular technology (5G). 5G is a new global wireless standard after 1G, 2G, 3G, and 4G networks [6]. It was proposed and started its commercial deployment in 2019 [7]. Compared to the previous 2G, 3G, and 4G Long Term Evolution (LTE), 5G operates in an additional millimeter-wave (mmWave) spectrum from 28 GHz up to 95 GHz to provide a larger band of frequencies [8]. As a result, it enables a peak throughput of 10-20 Gbps, 100 times faster than 4G LTE networks. More than increasing the speed, 5G also contains technologies enabling approximately 1 ms latency in data delivery, increased energy efficiency consumption, massive device communication, etc. [9]. These attributes make new experiences and services in IoT connectivity and applications possible [10]. Three new service areas were categorized, which are enhance mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable and low latency communication (uRLLC). The overall vision for these three broad 5G usage families and their basic service requirements are illustrated in Figure 1.  
With the support of 5G in communication, the utilization of IoT to support building fire evacuation will become a reality. A wide variety of IoT applications can be utilized for improving evacuation in high-rise buildings.