  5G and 6G wireless communications allow for novel and disruptive
applications. While 5G was strongly focused on improvements on QoS and QoS
guarantees that are necessary for industrial deployments, 6G will have a
disruptive impact on possible use cases. Here, nearly each use case requires
time synchronization of the involved systems. While PTP in its variations, e.g.
IEEE 1588 v2.1 or IEEE 802.1AS, has established as standard for wireline
systems, time synchronization of wireless or hybrid systems is still subject to
research. Thus, the so-called RBIS protocol, which was originally developed and
investigated for Wi-Fi, is mapped to 5G. This is possible, because both systems
are infrastructure based and a suitable broadcast that fits to the requirements
of RBIS protocol can be found in the control layer of 5G NR. Even if the 1
microsecond requirement that is required by some applications is not yet
cracked, the accuracy of 1.3 microseconds and precision of <4.3 microseconds
for non-invasive extension of existing 5G deployments is highly promising.
