# Telemedicine: A Survey of Telecommunication Technologies, Developments, and Challenges
###### Abstract  
The emergence of the COVID-19 pandemic has increased research outputs in telemedicine over the last couple of years. One solution to the COVID-19 pandemic as revealed in literature is to leverage telemedicine for accessing health care remotely. In this survey paper, we review several articles on eHealth and Telemedicine with emphasis on the articles' focus area, including wireless technologies and architectures in eHealth, communications protocols, Quality of Service, and Experience Standards, among other considerations. In addition, we provide an overview of telemedicine for new readers. This survey reviews several telecommunications technologies currently being proposed along with their standards and challenges. In general, an encompassing survey on the developments in telemedicine technology, standards, and protocols is presented while acquainting researchers with several open issues. Special mention of the state-of-the-art specialist application areas are presented. We conclude the survey paper by presenting important research challenges and potential future directions as they pertain to telemedicine technology. COVID-19; eHealth; Internet of Things; communication protocols; telecommunications; telemedicine +
Footnote †: journal: _Sensor and Actuator Networks_  
deployment of telemedicine could greatly reduce congestion in hospitals, and consequently limit the spread of infectious diseases. The advent of the COVID-19 pandemic has increased the need to leverage the benefits of telemedicine and eHealth. Telemedicine and eHealth research has seen an upsurge in recent works [5]. For instance, the authors of [6] examined variability in services between in-person and telemedicine. The method adopted involved analysis of 1104 patients. Comparing patients seen in-person to those seen by telemedicine revealed telemedicine to be an acceptable alternative to in-person evaluation for routine pediatric clinical genetics care. This result affirms similar conclusions in [7; 8; 9; 10; 11]. Several studies have encouraged the use of telemedicine in the post-COVID-19 era [12; 13; 14; 15]; as such, there is a need for a review of telecommunication technologies towards the realization of fully functional telemedicine services. This survey work presents previous work carried out by other researchers with respect to the different communication technologies that have been deployed in telemedicine. Among these technologies are internet and wireless technologies for digital data transmission, mobile telemedicine, wireless design, WBAN, satellite-based communication, and cellular technologies, including the use of infrared links. A general overview of telemedicine systems is presented in Figure 1. For telemedicine applications, communications can be classified as follows:  
* Body Area Communication: communication between patients and telemedical devices such as the wearable sensors;
* Remote Communications: communication between the telemedical devices and remote servers, including satellite, internet, GSM, and WAN communications;
* Communication based on application area, including communication for emergency telemedicine, video conferencing, and transmission of medical images. Connectivity protocols/standards required for communications technologies in telemedicine consist of ZigBee/IEEE 802.15.4, Bluetooth/IEEE 802.15.1, WiMAX/IEEE Broadband Wireless Access (BWA) 802.16, Wi-Fi/WLAN/IEEE 802.11, User Datagram Protocol (UDP), Real-Time Protocol (RTP), and Real-Time Transport Control Protocol (RTCP) and TCP/IP. Again, this research work essentially focuses on reviewing communications technologies utilized in telemedicine implementations, issues and challenges associated with deployment, and standardization and future directions for further research. Despite several efforts by researchers in the existing literature, no standard format has been developed for medical data communication in telemedicine [16].