Dr. Calhoun has spent 25 years in the high-tech segment of the wireless communications industry. He is a co-founder of InterDigital Communications Corporation (NASDAQ: IDCC), where he was involved for twelve years in the pioneering development of digital cellular technology, including the first systems based on TDMA technology (the architecture underlying approximately 80% of today's cellular networks). InterDigital currently carries a market capitalization of more than $1.5 billion. Subsequently, he was Vice-Chairman of Geotek Communications, and was Chairman of the company's engineering joint venture with the Rafael Armament Development Authority, a branch of the Government of Israel, based in Haifa, to develop a spread spectrum frequency-hopping radio system for fleet radio communications. Most recently, Dr. Calhoun was the Chairman and CEO of Illinois Superconductor Corporation (AMEX: ISO), a public company focused on the application of high-temperature superconducting materials and advanced signal processing techniques to the suppression of interference in wireless networks.
Like many other U.S. companies, Walmart has set up a robust supply chain over many years in China.