## 2 Background
### Healthcare  
As well as other factors related to the pandemic, such as high prices, long distances, and quarantine requirements, the world is currently shaped by epidemics and infectious diseases spreading more widely, including COVID-19. Many elderly and disabled people suffer from chronic diseases, so it is difficult, if not impossible, for them to go to medical centres [39]. A practical, comprehensive, computer-aided technology is therefore essential to offer patients long-term care and remote medical monitoring while minimizing financial burden. Through the analysis of large amounts of data, IoT has revolutionized sanitary systems, turning them into intelligent and predictive systems. IoT devices have been connected to record patients' physiological data instantaneously, including blood glucose levels, temperature monitors, and other crucial information. Patients will benefit from novel medical services, including early diagnosis and continuous monitoring of serious diseases [40; 41]. The IoT has several applications in the field of health care, including remote clinical monitor ing, assisted living, chronic disease management, and preventative treatment. In addition, there are a number of IoT applications in healthcare, including home healthcare, mobile health, and e-healthcare. As a result, IoT technology has allowed healthcare processes to be managed smartly, and self-care is possible. To prevent pharmaceutical errors and human error, some events can be identified, such as seizures, falls due to Parkinson's disease, stroke rehabilitation, neurologic monitoring, and heart monitoring [42; 43; 44]. However, further hurdles remain to be overcome in order to produce successful and safe healthcare applications [45; 46]. Numerous security protocols are available today to preserve data from assaults and threats. The perception layer, networking layer, middleware layer, and application layer make up the HIoT system's prominent basic four-layered architecture. The following are the explanations of the layers. 1. Perception Layer: At the bottom of the hierarchy, we have this layer, which we may refer to as 'hardware' or 'physical'. By collecting and signalling data, this layer prepares data for transmission to the network layer. 2. Network Layer: In this layer, all smart devices are connected, and health data can be exchanged among them. The cutting-edge technologies used by this layer allow patients to securely transmit and receive health data from the base station. 3. Middleware Layer: In this layer, services are dispensed with names and addresses associated with requests. Non-homogeneous items can be used with HIoT applications without requiring peculiar equipment platforms. Health data are collected from the network layer and cached here. 4. Application Layer: Data from other layers are analyzed and combined in this layer to dispense healthcare services. Healthcare services can be dispensed at this layer to meet the needs of patients. In this layer, graphs, business models, and flowcharts that control all activities and healthcare services can be produced. HIoT systems cannot succeed without technological innovations, business models, and appropriate business models. An IoT-based healthcare system known as HIoT also consists of three key phases of a workflow, namely data creation, data processing, and information consumption. The phases mentioned are described as follows. 1. Data generation: The process of generating the required data involves using a variety of sensors, medical devices, and even direct data entry by patients or other involved healthcare teams. The perception layer is used for this phase, while the network layer is used to transpose the data collected. 2. Data processing: In the data processing stage, collected data are analysed using well-known mechanisms including machine learning techniques and data analysis tools. Through the middleware layer, this stage is completed. 3.