This disclosure describes techniques for generating depth maps for video units, such as video frames or slices video frames. The transponder device has one or several transponder aerial and a transponder circuit connected to the transponder aerial for receiving an RF signal through the transponder aerial. Time stamps in the MPEG compatible datastream are unaffected by the insertion of the auxiliary information. An elevated piston seal flange in the manifold allows flow to be exact with plugged or partially plugged primary orifices. Two adjacent radiators may be associated with a feed point and a ground point, respectively, and the feed point and the ground point may be disposed in the proximity of the first gap. The group GW is also configured with the first group key for authenticating each of the MTC UEs as the member of the group.