She was asleep and woke up to find an old man touching her below the waist

A judge has sentenced an Atlanta man to six months in federal prison for fondling a sleeping woman on a Delta Air Lines flight from Dallas to Atlanta last year.

Authorities said a 20-year-old woman seated next to Ranchhodbhai Lakha, 61, woke up to find him touching her below the waist during a September 28, 2010 flight.

Lakha touched her again after she objected, prompting her to get up and report the assault to a flight attendant, according to prosecutors.

Lakha pleaded guilty to a charge of abusive sexual contact.

"This defendant thought he could get away with taking advantage of a defenseless, sleeping passenger sitting next to him," U.S. Attorney for the Northern District of Georgia Sally Yates said in a statement.

"He was wrong."

The federal judge also ordered the man to serve a year of supervised release after he is out of prison.

Plus, Lakha will have to pay a $5,000 fine and must register as a sex offender, the U.S. Attorney's Office said.