From Halopedia, the Halo wiki
The Noble Map Pack Trailer music is a standalone track released by Bungie with the 10/29/10 Bungie Weekly Update. It was, as the name implies, used in the Noble Map Pack Trailer. The song runs for one minute and thirty-two seconds.
The song combines the Halo Theme variations from Halo: Combat Evolved, Halo 2, Halo 3 and Halo: Reach, with other motifs from the latter also present.
Each song in the trailer is set to correspond with a specific map; thus, the Halo Theme plays during the section for Anchor 9, Mjolnir Mix plays for Breakpoint, and One Final Effort plays for Tempest.