An Access Time Pattern determines when a tagholder has access to an area. When an Access Time Pattern and an area are linked, they form an Access Description.
I think either is permissible, and if you want to avoid contention, you can use a hyphen! One word is probably more usual in a computing context. A "Tag holder" is likely to be one of those plastic badge holders you get at conferences.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.