  The increasing popularity of ultra-wideband (UWB) technology for
location-based services, such as access control and real-time indoor
track&tracing, as well as UWB support in new consumer devices such as
smartphones, has resulted in the availability of multiple new UWB radio chips.
However, due to this increase in UWB device availability, the question of which
(industry) standards and configuration factors impact UWB interoperability and
compatibility becomes increasingly important. In this paper, the fundamentals
of UWB compatibility are investigated by first giving an overview of different
UWB radio chips on the market. After that, an overview of UWB standards and
organizations is given. Next, this overview is used to discuss the focus of
these different standards and to identify the differences between them. We
describe compatibility issues and associated interoperability aspects related
to physical (PHY), medium-access-control (MAC) and upper layers. For the PHY
layer, compatibility is possible for all UWB radio chips if the correct
settings are configured. For the MAC layer, the implementation of the multiple
access scheme as well as the localization technique is mostly proprietary. For
the device discovery, several standards are currently being drafted. Finally,
future challenges related to UWB interoperability are discussed.
