British Telecommunications has filed a law suit against Google Inc. (GOOG),  for allegedly infringing six U.S. patents for mobile-device technology in federal court in Wilmington, Delaware.

The complaint said “BT has invested heavily over the last 20 years,” generating “numerous patents,” and Google’s products including the Android operating system, maps, search, music and book services wrongly “incorporate BT’s patented technologies,

Apart from this, BT is locked in a legal battle with U.S. cable company Cox Communications Inc. Last year it sued Cox Communications Inc. in the same court over four patents for transmitting data over cable networks. A trial in that case is tentatively scheduled for 2014, according to court papers.

“We believe these claims are groundless,” Jim Prosser, a Google spokesman, said in an e-mailed message. He said the company would defend against them.