Most investors expect the Fed to raise interest rates at its Dec. 15-16 policy meeting, but many also realize the central bank's pace of tightening boils down to stronger U.S. economic numbers. The dollar's prospects for 2016 rest on investor conviction that the Fed will raise U.S. borrowing costs faster than the gradual pace the central bank has communicated to markets, said Karl Schamotta, director of currency risk and strategy at Cambridge Global Payments, which hedges currencies for corporations.