In the early 1990s, ADC launched an R&D effort to break into the broadband data transport market. Spending some $250 million, ADC engineers invented and brought to market synchronized OFDMA and built and deployed more than 100,000 OFDMA modems. ADC said the U.S. Patent Office has issued more than 40 patents based on ADC's work with 70 more patents pending. Now that WiMAX and LTE are gaining traction in the industry, ADC decided to have its coming out party.
According to Phil Caspers, IP counsel with ADC, some examples of the company's patents include: a synchronized multi-point to point OFDMA system; OFDM tone allocation, which addresses QoS; contention-based bandwidth request; and multi-frame synchronization.