A system for measuring the time interval of a signal. of a housing which is a member for fitting the outer ring and by fitting the projection 12d of the retainer to the recess portion, not only the outer ring but also the retainer can be constituted to be unable to rotate relative to the housing, the relative rotation between the outer ring and the retainer are substantially made unable to carry out in the state via the housing. A suspension assembly includes a suspension structure. Each projection 5 has a pair of opposing first walls 51 parallel to the first direction and a pair of opposing second walls 52 parallel to the second direction. Each of said fluid-support-structures has at least one dimension of about 1 millimeter or less, and the fluid-support-structures are moveable in response to a volume transition of the volume-tunable-material. The method includes receiving relay link resource information, determining whether a current link is a multi-hop link by using the relay link resource information, and if the current link is the multi-hop link, allocating a corresponding relay link resource as the P2P resource by determining a serving station.