He was an American engineer who led the team that in 1972–73 built the first mobile cell phone and made the first cell-phone call. He is known as the father of the cell phones. He joined the U.S. Navy and served during the Korean War. Cooper worked on many projects involving wireless communications, such as the first radio-controlled traffic-light system, which he patented in 1960, and the first handheld police radios, which were introduced in 1967. He later served as a vice president and director of research and development (1978–83) for the company.