The vast deployment of the Internet of Things, Wireless Body Area Networks (WBANs), and the associated standards (e.g., IEEE 802.15.4 [
11] and IEEE 802.15.6 [
12]) have boosted the emergence of smart healthcare systems. Despite their acceptance in the healthcare sector, smart healthcare systems still face challenges that hinder their large-scale deployment. This section surveys scholarly research studies that tackle the large-scale deployment of smart healthcare systems. This section starts with a literature review of IoT and its architectures, applications, and protocols. Then, it reviews topics related to Wireless Body Area Networks, as these networks play an essential role in the context of smart healthcare systems. Finally, a discussion of the network management of IoT systems is presented.
2.1. Internet of Things
Interest in IoT has increased among industrial and academic institutions, which has necessitated the development of testbeds and platforms to evaluate IoT solutions. Gluhak et al. identified some requirements for IoT experimental facilities [
13]. They surveyed currently available research testbeds and suggested new directions. The development of IoT-based systems is an incremental process starting from existing technologies and applications. IoT-based systems should comply at a minimum with these non-functional requirements: heterogeneity, scalability, ubiquitous data exchange through proximity wireless technologies, energy-optimized solutions, localization and tracking capabilities, self-organization capabilities, semantic interoperability as well as data management, and embedded security and privacy-preserving mechanisms [
14].
Even though IoT is envisioned to augment the global Internet and make a unified mega-network that connects the physical and digital worlds, current Internet protocols may not apply to IoT due to its resource-constrained devices. Therefore, the IETF is developing new protocol suites tailored to the IoT paradigm [
2]. Al-Fuqaha et al. [
4] summarized the most relevant protocols and discussed some application issues related to IoT. They also discussed relations between IoT and emerging technologies like big data and cloud computing. Whitmore et al. [
15] presented the current state of research on IoT through an intensive literature review. They identified current trends and described challenges that threaten IoT diffusion. Interested researchers in this area may consult the same paper for open research questions, future directions, and a comprehensive reference list.
As of today, IoT consists of heterogeneous devices, technologies, and protocols, making it difficult for hardware and software developers to develop applications that seamlessly integrate. This heterogeneity necessitates the involvement of middleware that supports standard functional and non-functional IoT requirements [
16]. In addition, middleware provides hardware and software abstractions that facilitate developers’ work so that they focus more on their applications. IoT-based applications generate considerable data (i.e., big data) that require storage, analysis, and ease of access. These requirements pose challenges for systems deployed within enterprises. Therefore, there is a need to integrate cloud computing and IoT [
17]. This work provided a literature survey on integrating the cloud, IoT, and applications. They also discussed the available platforms for cloud and IoT integration.
Mobility management is an inevitable requirement for the IoT paradigm. Objects attached to people, vehicles, animals, etc., move with their hosts’ bodies. Mobility represents a significant challenge for IoT, which requires extensive research to develop suitable algorithms and protocols to handle it. Ghaleb et al. [
18] reviewed and discussed algorithms to address IP integration challenges with resource-constrained IoT devices. They also provided a comprehensive review encompassing the mechanisms, advantages, and disadvantages of related works on IPv6 mobility management. For areas with poor social infrastructures and information communication infrastructures, IoT can be deployed to provide an IoT-based mobility information network [
19]. An IoT-based mobility management information network consists of fixed wireless nodes deployed on many roads (semi-electrostatic field sensor, acceleration sensor, gyro sensor, temperature sensor, humidity sensor, infrared sensor, and sensor server) and mobile nodes. Mobile nodes collect data captured by road sensors while moving along the roads and transmit them via the Internet to residents. Such transmitted data are intended to help in disaster prevention, sightseeing information, and shopping.
Fifth-generation (5G) mobile networks have become the preferred choice for connecting IoT devices to backend systems, offering capabilities far beyond those of fourth-generation (4G) networks [
20]. While 4G supported the initial wave of IoT adoption, the rapid growth in IoT devices and applications soon exceeded its performance limits, particularly in bandwidth, latency, and overall network efficiency. The transition to 5G has significantly expanded the scope of IoT, offering remarkable speed and ultra-low latency. It provides tailored solutions to meet the diverse demands of IoT applications, particularly in healthcare, where real-time data transmission, remote monitoring, and telemedicine services are critical for improving patient outcomes and operational efficiency. Mahdi et al. [
21] reviewed ongoing advancements in IoT, highlighting the transformative impact of 5G while exploring the potential of sixth-generation (6G) networks to meet future demands for ubiquitous IoT connectivity and enhanced service capabilities.
Stankovic [
22] identified eight key research areas that tackle existing challenges and encourage further investigation. These areas include large-scale system expansion, architectural design, interdependencies in knowledge generation and big data, system resilience, openness, security, privacy, and human-in-the-loop considerations. Despite these advancements, numerous unresolved research challenges remain, primarily due to the complex nature of system deployment and the strict requirements imposed by various services utilizing these complex frameworks. Therefore, it is essential to examine existing standardization efforts, explore ways to enhance them, and identify research opportunities that will contribute to the advancement of the IoT field.
IoT influenced enterprises’ and governments’ digital strategies with disruptive business models and fast-changing markets. Many vertical industrial sectors, like transportation, healthcare, and logistics, have incorporated IoT into their digital strategy. IoT still experiences heterogeneity issues in devices, technologies, and protocols. These heterogeneity issues impose challenges on new IT strategies. Zimmermann et al. [
23] described a new meta-model-based approach for integrating IoT architectural objects semi-automatically federated into a holistic digital enterprise architectural environment. The large-scale deployment of IoT in various vertical applications is still a challenge. The most important is the diversity of protocols developed for IoT and WSNs [
24]. For a recent survey of IoT architectures, protocols, and challenges, the reader may refer to [
25].
IoT provides several services that can be utilized to create many vertical applications. IoT services can be divided into four categories: identity-related services, information aggregation services, collaborative-aware services, and ubiquitous services [
26]. IoT applications may use the services of one or more of these categories. Moreover, IoT services are essential to application developers to help them focus on their tasks, while the services are provided through some middleware technologies.
Cook et al. [
27] presented a full-fledged smart home application based on the ZigBee WSN. This is a product in a box that can be easily installed in homes to monitor specific parameters. The product utilizes recent application protocols developed initially for WSNs and later adopted for IoT. Smart homes can be connected through their gateways and form a smart community [
28]. An innovative community could provide useful services to its residents, specifically the elderly and residents with disabilities, by incorporating smart healthcare and connecting it to a community call center. Another exciting possible application of IoT is smart cities that allow municipalities to incorporate IoT into their cities [
29].
2.2. Smart Healthcare
Smart IoT objects fulfill the requirements of ubiquitous communication, pervasive computing, and ambient intelligence [
30]. These characteristics have encouraged scientific and industrial developers to propose services and applications for the healthcare industry. A direct and useful application of IoT in healthcare is the Ambient Assisted Living (AAL) application, which aims to help older people and people with disabilities and chronic diseases live their everyday lives without being restricted by conventional monitoring and assistive tools. Also, people can stay in their homes and receive treatment similar to that which they would receive if admitted to a hospital [
31]. Bui et al. [
32] inferred the non-functional requirements for smart healthcare applications through the storyline of a person with diabetes. They highlighted the requirements for interoperability, bounded latency, reliability, and security as the main ones for successful monitoring and supervision. IoT can be used to manage the administration of diabetic therapy by developing a personal device to assist and manage the insulin therapy dosage calculation [
33]. The authors provided an overall architecture based on new communications protocols developed by the IETF that enable the connectivity of personal devices with the global Internet. A new concept called ‘Health Internet of Things (HIoT)’ was proposed to exploit sensor technologies and wireless networks for monitoring medical conditions [
34]. This work presents an interconnection framework for mobile Health (mHealth) based on IoT.
Jung [
35] explored how wearable and motion sensors, in the context of a smart home, can be used to monitor the movement of senior citizens by continuously logging and reporting their vital signs and the surrounding environmental conditions. It is worth mentioning that pervasive computing, as part of the IoT paradigm, is becoming an essential part of consumers’ electronics and can be integrated with a smart home environment to adopt a smart-home-based healthcare model [
36]. Collected data from various sensors deployed throughout the home can generate a smart home visualization system that provides different analyses to help detect and understand abnormal behaviors of targeted household residents [
37]. Integrating mobile health as part of smart cities is becoming inevitable [
38]. The authors provided an overview of how smart health can complement mobile health as part of a smart city initiative. They discussed the various aspects needed to achieve a comprehensive strategy for providing smart healthcare applications as part of a smart city environment. Ghose et al. [
39] proposed a mobile software platform for ubiquitous healthcare support in homes and small clinic areas. The IoT platform replaces the PC gateway used in traditional telemedicine with a mobile device to ensure mobility support. Santos et al. [
40] proposed an IoT-based mobile health and patient monitoring application. The proposed application is a set of health monitoring services deployed in a mobile gateway device. It collects real-time information about the user’s heart rate, location, and environmental conditions and forwards them to an intelligent personal assistant platform called AMBRO. Pereira et al. [
41] studied the performance of IoT-based mobile e-health applications and services.
Khattak et al. [
42] conducted a comprehensive survey on the technologies and methodologies used for connecting and monitoring medical sensors. They introduced a testbed architecture specifically designed for healthcare applications. Similarly, Rahmani et al. [
43] proposed the Smart e-Health Gateway, a system that facilitates the connection between sensor networks and the Internet. This gateway effectively addresses several challenges in ubiquitous healthcare systems, including energy efficiency, scalability, and reliability. Implementing Smart e-Health Gateways on a large scale can significantly enhance ubiquitous health monitoring, particularly in clinical settings. Additionally, they introduced a framework designed for various healthcare environments, including hospitals, specialized clinical settings, patient homes, senior citizen residences, gyms, and mobile healthcare services such as ambulances, mobile clinics, and travel health services.
Islam et al. [
44] conducted a review of research on advancements in IoT-driven healthcare technologies. They analyzed cutting-edge network architectures, platforms, applications, and industry developments within IoT-based healthcare solutions. Furthermore, they proposed an intelligent collaborative security framework aimed at mitigating security threats. Their study also explored how emerging technologies such as big data, ambient intelligence, and wearable devices can enhance healthcare applications. Additionally, they examined global IoT and eHealth policies and regulations, assessing their economic and societal impact on sustainable development.
Farahani et al. [
45] presented an architecture for applying IoT in healthcare and medicine. The architecture is patient-centric, where all constituents, such as the hospital, patients, and services, are seamlessly connected. The architecture consists of three layers, the device, fog computing, and the cloud, to empower handling complex data in terms of variety, speed, and latency. They also addressed the challenges of IoT eHealth, such as data management, scalability, regulations, interoperability, device–network–human interfaces, security, and privacy. Smart healthcare systems may proactively manage the patient’s health—prevent disease, detect disease early, and improve healthcare outcomes [
46]. Adame et al. [
47] developed a platform for monitoring healthcare environments that integrates RFID and WSN technologies, providing the location, status, and tracking of patients and assets.
2.3. WBAN
The IEEE 802.15.4 standard, published in 2006, specifies the PHY and the MAC layers for short-range, low-power, low-cost, and low-bit-rate networks. These capabilities make it suitable for general WSN applications and IoT applications. However, IEEE 802.15.4 was not intended to support wireless communications in the vicinity of or inside the human body [
12]. Therefore, IEEE 802.15 Task Group 6 initiated WBAN standardization activities in November 2007. The group recognized that existing standards did not fully meet the medical (i.e., proximity to human tissues) and relevant communication regulations for some application environments. The first draft was released in May 2010, and the final version was published in February 2012. IEEE 802.15.6 is targeted to serve a range of medical and non-medical applications.
Since its initial release, the IEEE 802.15.6 standard has undergone revisions to accommodate emerging use cases. The IEEE 802.15.6ma project is updating the standard to improve dependability for Human Body Area Networks (HBANs) and expand its applicability to Vehicle Body Area Networks (VBANs) [
48]. Additionally, an amendment has been introduced to enhance the Ultra-Wideband (UWB) physical layer (PHY) and medium access control (MAC) to support more reliable communication in HBANs [
49]. These advancements reflect ongoing efforts to refine WBAN standards to address modern medical and non-medical requirements better.
Cavallari et al. [
50] surveyed the main WBAN applications, technologies, and standards, as well as issues related to WBAN design and evolution. They also presented a comparative study of the WBAN standards with simulation and experimental results. In another work [
51], the authors surveyed the current state-of-the-art WBANs based on the latest standards and publications. They also discussed some open issues and challenges with WBANs. Healthcare systems in residential environments use WBANs for remote monitoring and health management. Ghamari et al. [
52] provided an architecture for residential environment healthcare systems and stated the technologies and networks needed in such an environment.
2.4. IoT Network Management Protocols
The Simple Network Management Protocol (SNMP) is the standard management protocol for traditional TCP/IP networks. However, several issues make SNMP ineffective for IoT. Firstly, the communication overhead associated with SNMP is significant for low-bandwidth and low-power wireless IoT links. Secondly, SNMP follows a centralized management approach where the management station pulls the managed nodes at specified intervals. Thirdly, Management Agent and Management Information Base (MIB) object variables should be configured at each sensor node, which often has limited storage. Finally, SNMP may not adequately handle sensor-specific failures, which is common in IoT [
53].
Sheng et al. [
54] conducted a review of IoT network management and highlighted that, despite extensive research on various aspects of sensor networks, the management of sensor devices remains largely unexplored. To bridge this gap, a lightweight web service grounded in REST (Representational State Transfer) principles was introduced to streamline wireless sensor device management. Leveraging IPv6-based open standards, the service enables access to resource-restricted wireless networks. Specifically, it incorporates essential IETF protocols intended for such environments, including IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs), the Routing Protocol for Low-Power and Lossy Networks (RPL), and the Constrained Application Protocol (CoAP). A CoAP-driven device management method further simplifies the administration and accessibility of IPv6-capable sensor devices.
Given that end-to-end connectivity in IoT environments involves multiple networks with varying performance and connectivity requirements, sectional monitoring is suggested as a more effective management strategy [
55]. Furthermore, a layered fault management scheme is recommended for end-to-end transmission to accommodate the heterogeneous nature of IoT networks.
Lindholm et al. [
56] examined the feasibility of deploying SNMP (Simple Network Management Protocol) in IoT environments and found it to be highly challenging, despite its established usefulness as an Internet management protocol. By leveraging the CoAP protocol, they explored techniques that enable SNMP-based tools and applications to coexist and interact with CoAP-enabled endpoints. While SNMP has the potential to manage sensors in IoT networks [
57], its implementation is impractical due to excessive memory and power consumption, as well as increased communication overhead.
Fault tolerance is a critical yet challenging non-functional requirement in IoT systems, particularly in healthcare applications. While fault tolerance mechanisms can be effectively applied to IoT applications such as smart homes [
58], they may not be suitable for certain smart healthcare scenarios, such as implanted sensors. A study in [
59] explores the opportunities and challenges of healthcare monitoring and management within the IoT framework, incorporating cloud-based processing. The same study also reviews the current state and future directions for integrating remote health monitoring technologies into clinical medical practice.
Gia et al. [
60] propose an IoT-based architecture that supports scalability and fault tolerance in healthcare applications. However, their approach primarily addresses faults in a reactive manner, meaning it lacks proactive mechanisms to assess the condition of sensor nodes and prevent failures in advance.
The widespread adoption of smart applications and services is expected to generate vast amounts of data, including text, audio, and video, necessitating batch, interactive, or real-time processing. One of the key challenges is the integration of heterogeneous data from multiple sources [
61]. To address this, researchers have developed a flexible and cost-effective infrastructure that incorporates cloud and fog computing, blockchain technology, and message brokers to enable secure and private IoT deployment for smart healthcare applications and services. Another major challenge is efficiently managing this large volume of data throughout its lifecycle.
Gharaibeh et al. [
62] take a data-centric approach, outlining key data management techniques designed to ensure the consistency, interoperability, granularity, and reusability of IoT-generated data in smart cities. Additionally, they identify security and privacy strategies while discussing the networking and computing technologies that support smart city implementations [
63].
The Open Mobile Alliance (OMA) SpecWorks [
64] developed a device management protocol called LightweightM2M (LwM2M). The protocol is designed for sensor networks and supports a machine-to-machine (M2M) environment. It has also been developed to manage lightweight and low-power devices on various networks, which is necessary to realize the potential of IoT. The LwM2M protocol features an architectural design based on REST. It defines an extensible resource and data model and builds on the CoAP standard, making it suitable for the remote management of M2M devices and related service enablement.
The Message Queuing Telemetry Transport (MQTT) protocol, widely used in IoT systems, is vulnerable to various cyberattacks, including replay and Man-in-the-Middle (MITM) attacks. A novel cyber range system was proposed in [
65] to analyze vulnerabilities and implement countermeasures. This system provides an experimental environment for real-world attack scenarios, supporting new research to enhance MQTT protocol security and ensure robust communication in IoHT systems.
To address network congestion and reliability issues in IoHT, an adaptive data communication model was introduced in [
66]. The model ensures efficient and reliable data transmission in high-traffic scenarios by dynamically switching between MQTT-SN and CoAP protocols based on network conditions.
A hybrid network management system combining the NETCONF protocol and decision tree algorithms was designed to improve configuration efficiency and fault diagnosis in IoHT networks [
67]. This system achieves a fault diagnosis accuracy of 96%, outperforming traditional methods and demonstrating the potential of AI in enhancing network management scalability and adaptability.
A comparative analysis of the Lightweight Machine to Machine (LwM2M) and Extensible Messaging and Presence Protocol (XMPP) highlights their suitability for IoHT applications in [
68]. While LwM2M offers efficient device management and low power consumption, XMPP supports robust messaging in constrained systems. The study recommends protocol selection based on specific IoHT application needs.