David Bowie's 1974 song (and album) 'Diamond Dogs' was a musical adaption of George Orwell's famous book '1984'.
Hideo Kojima is a known David Bowie fan and in the Metal Gear Solid 5 trailer, it is stated that Big Boss has been in a coma for 9 years; 'Metal Gear Solid: Peace Walker' - which precedes the events of MGS5 - was set in November 1974, placing MGS5 in late 1983 or (more probably) 1984, the year of George Orwell's novel, with Big Boss shown to be part of a new squad known as 'Diamond Dogs', a direct reference to the album.