In The Unicode Standard, Braille Patterns implementation is discussed in Chapter 21 Notational Systems: Shorthands, Braille, Musical Symbols.
Braille Patterns were encoded in The Unicode Standard version 3.0. It is encoded in the following block:
|Blocks||Character Range||Added in Unicode Version||Documentation|
A number of proposals for its inclusion were submitted to the Unicode Technical Committee and WG2 (most of the documents leading to the encoding of Braille do not appear to be online):