Abstract
The use of shared and unlicensed radio spectrum has been the impetus of innovative and widely used technologies (e.g., Wi-Fi, Bluetooth, and others)-driving the scene of ubiquitous connectivity for devices, sensors, and peripherals in an encompassing Internet of Things (IoT). However, coexisting technologies operating in unlicensed bands need to share limited spectrum resources while attempting to offer desired performance. This could prove challenging as channel access is not guaranteed, which raises concerns for wireless coexistence in sensitive applications like medical devices. In this article, we provide a brief review of topics forming the current stage of wireless coexistence in research, industry, and regulatory circles. We present the standardization activities for the evaluation of wireless coexistence, and recent advancements of unlicensed spectrum technologies such as Wi-Fi, Bluetooth, and Long Term Evolution (LTE) in unlicensed bands, along with proposed evaluation methods.