Free agent Paterson joins on a six-month deal, while 19-year-old right-back Anthony O'Connor has signed an initial one-month loan deal from Blackburn.
Paterson told the club's official website: "I want to show people what I can do. I'm looking forward and raring to go. The most important thing is to get back out playing.
"I'm here to work hard, I'm looking forward to the challenge, we've got a great bunch of lads here.
"My pre-season hasn't been spot on but I've looked after myself and I feel great."