A cooling device includes: a cooling fan; a shroud provided at an outer circumferential side of the cooling fan; an inner circumferential wall provided on the shroud and adjacent to the outer circumference of the cooling fan; and an outer circumferential wall provided to surround the inner circumferential wall. The architecture allows insertion of discrete individual fields, referred to as \u201cfree floating fields\u201d, inline with normal textual sentences. The second pilot carrier has a mean frequency that is a fraction of the time division duplexing frame rate and is also orthogonal to the other carriers used in the multi-carrier communication system. In another embodiment, the gaming system uses an accumulated quantity of progressive event points to determine the designated player’s probability of winning one or more of the progressive awards.