# A Review of Internet of Things Technologies for Ambient Assisted Living Environments
## 1 Introduction
The needs of older people can be solved by adopting the appropriate IoT technological solutions [11] and global services specifically targeting older people [12], such as location-based services to support freedom of movement and greater independence [13]. Modern assistive technologies (or gerontechnologies [14; 15], in case of assistive technologies used for improving wellbeing of for older people) constitute a wide range of technological solutions aimed at improving well-being of older people [16] (Figure 1). These technologies are used for personalized medicine, smart health, health tracking, telehealth, health-as-a-service (HaaS), smart drugs and multiple other applications. Figure 1: Applications of internet of things (IoT) technologies for the ambient assisted living (AAL) domain. Since one of the most relevant challenges is to enable older people to live as much as possible independently at home, it is crucial to investigate how gerontechnologies could support them in the context of home environment. Different types of assistive technologies, information technology (IT) and ICT, are developed and mixed for newer and more complex and comprehensive solutions. In general terms, there are the following research areas of gerontechnologies:  
* Social inclusion and communication: technologies that aim to enable older people to communicate and interact with others, like family members and friends, in order to maintain their social life and thus improve their well-being [17];
* Psychosocial factors of human-technology interaction and usage: some socio-economic and psychological aspects are relevant for understanding how different profiles of older people interact with and use technologies [18];
* Telemedicine, telehealth and telecare: in order to enable a continuous monitoring of eventual health problems and long-term conditions, typical of older age, remote services offered by healthcare organizations could widen the possibility for older people to access appropriate care and thus improve their health status and clinical outcomes [19];
* Entertainment and media: serious games and smart objects at home could facilitate the daily living of older people by enabling alternative commands for home management or being engaged in proper physical or mental training [20; 21];
* Sensing and interacting: sensors installed at home represent a great opportunity for the monitoring of older people's activities and behaviors, as well as the detection of sudden risks or accidents [22]. Such information, when appropriately treated, could be notified to eventual family caregivers or care services for immediate intervention when a problem occurs. The previous surveys on the IoT primarily focused on discussing the evolution of IoT across different domains of application [3], or specifically focused on the applications in the healthcare domain [4]. Other surveys focused on opportunities and limitations of current IoT healthcare systems, and frameworks in the context of fog computing [23; 24; 25]; discuss current implementations for home-based tele-monitoring and smart home technologies that support healthy aging [26]; review applications, services and security and privacy issues of IoT in healthcare frameworks and systems [27]; introduce a systematic IoT in e-health ecosystem, discuss security issues in IoT devices and networks, and consider challenges and future directions for IoT in e-health [28]; discuss smart homes, including medical sensors, actuators and ICT, which enable continuous tele-monitoring of older people's health and wellbeing [29]; overview different types of sensors and communications methods in various IoT systems in healthcare applications [30]; analyze the role of cloud-based computing for critical IoT systems in healthcare [31]. The aim this paper is to present the comprehensive overview of the challenges raised and solutions provided by IoT technology to the domain of AAL systems and assistive technologies.