Stepped AGC for OFDM wireless communications: U.S. Pat. No. 7,697,644

U.S. Patent No. 7,697,644, issued on April 13, 2010 to Newport Media, Inc. of Lake Forest, CA, discloses a system and method for stepped automatic gain control (AGC) for wireless communication systems.

Orthogonal-frequency-division-multiplexing (OFDM) is a  technique used in wireless communications to transmit multiple signals simultaneously over a single transmission path while reducing various unwanted effects, such as cross-talk between the signals.  Automatic gain control (AGC) allows the receiver to counteract large variations in the received signal.  However, as disclosed by the patent, in OFDM, glitches or sudden changes in the signal level can cause significant losses of data, and AGC can contribute to such sudden changes.  The patent discloses a system and method for using OFDM with stepped AGC to automatically control the gain of the receiver while avoiding such performance losses.

According to its website, Newport Media is a fabless semiconductor producer of highly integrated solutions for emerging digital audio and mobile TV broadcast standards.  The company recently reported that it raised $15 million in a completed Series D financing and that Japanese electronics company ALPS Electric has formally qualified its 65-nanometer complementary metal-oxide-semiconductor (CMOS) single-chip solution and has begun production of the modules for Japan’s Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) digital television standard.  Newport Media is listed on the USPTO website as having 18 other issued U.S. patents besides the ’644 patent.