Gates (also known as Area-connecting Gates) are devices used by members of the Time Patrol and their allies to travel between different areas when on certain kinds of missions. Gates were first introduced in Dragon Ball Online and also appear in the Dragon Ball Xenoverse series.
Gates are hoop shaped devices that feature six emitters that can create portals that connect areas together allowing Time Patrollers to travel between two areas quickly regardless of distance making them a useful way to get around a timeline during missions that do not involve the use of Time Scrolls. These gates are commonly used in day to day operations of the Time Patrol such as Parallel Quests and Expert Missions. However they can only be used when the portal is open and unusable when closed. Typically gates open once an area has been cleared of enemies or some other task is completed. Some oddly remain closed throughout a mission (presumably malfunctioning or damaged) forcing Time Patrollers to use or find an open one that allows them to reach the area it is connected to as long as other gates are around that connect to the area in question as some areas are interconnected by gates though this usually requires the Patroller travel the long way around through multiple areas.
In the Xenoverse series, Time Patrollers can use an open gate by locking on to it and approaching it to travel to the area it is connected too. An image of the area it connects to will appear in the center portal of the gate when close to the gate while locked on to it and the name of the area is shown beside the button input prompt to enter it. In Scouter/Search View, it shows name of the area it connects to.
In Xenoverse 2, when their are no enemies on an area gate locations are indicated by gate icons. Green Gate icons usually reveal the quickest way to get through a quest. These icons make finding gates a lot easier a feature that was absent in Xenoverse which made it hard to find gates sometimes. This feature was presumably added to make determining their location easier and to make it easier to figure out where to go next. The Quest Info Screen shows a map featuring the areas that can be traveled to within the quest and shows which areas are connected to which by Gates.
In Dragon Ball Xenoverse 2, during certain Parallel Quests some enemies can perform a scatter attack which knocks Time Patrollers away sending them flying through gates which are then covered by a dark rock-like substance that closes them off. The Time Patroller will find themself transported to an area where they and any teammates knocked into the same gate must defeat an enemy to open gate that they can use to travel back to where they were fighting though they may sometimes have to go through several areas. Once back to the area they were originally fighting in, a Time Patroller can attack the dark rocks blocking other gates to break them opening the gate and freeing any allies trapped beyond them. Scatter Attacks cannot be avoided though they tend to be more of an annoyance however they put Time Patrollers at a disadvantage by scattering them forcing them to regroup which can cost precious time.