  The next generation communication systems are evolving towards an increased
flexibility in different aspects. Enhanced flexibility is the key in order to
address diverse requirements. This paper presents the significance of adaptive
guards considering a windowed-OFDM system which supports a variety of services
operating asynchronously under the same network. The windowing approach
requires a guard duration to suppress the out-of-band emissions (OOBE), and the
guard band is required to handle the adjacent channel interference (ACI) along
with the windowing. The guards in both time and frequency domains are optimized
with respect to the use case and power offset between the users. To fully
exploit and further increase the potential of adaptive guards, an
interference-based scheduling algorithm is proposed as well. The results show
that the precise design that facilitates such flexibility reduce the guards
significantly and boost the spectral efficiency.
