Golden Bridge Tech., Inc. v. Apple Inc., No. 13-1496 (Fed. Cir. 2014)Annotate this Case
A Code Division Multiple Access (CDMA) system wireless cellular network has a base station and mobile stations, such as cellular telephones. To establish communication between a mobile station and a base, the mobile station transmits a known signal (preamble) over a random access channel (RACH). The CDMA system allows multiple signals to be sent over the same RACH by using different numerical spreading codes that enable the stations to distinguish a particular wireless communication from other concurrent communications. If too many mobile stations transmit simultaneously at high power levels, the signals can interfere with each other. GBT’s patents disclose an improvement that reduces the risk of interference: a mobile station seeking to communicate with the base will transmit preambles at increasing power levels until it receives an acknowledgment signal from the base. Once the mobile station receives that acknowledgment, it stops transmitting preambles and starts transmitting message information, so that each data signal is transmitted at the lowest power necessary to reach the base, reducing the risk of interference. In Texas litigation, the court construed preamble as “a signal used for communicating with the base station that is spread before transmission” and granted summary judgment of anticipation, which the Federal Circuit affirmed. While appeal was pending, GBT sought new claims during reexamination of one patent and in a pending continuation application and submitted the claim construction order from the Texas litigation and filings setting forth GBT’s stipulated definition of preamble. The claims GBT asserted, in this case, against Apple were added during the proceedings. The district court construed the disputed terms, including preamble, and granted Apple summary judgment of noninfringement. The Federal Circuit affirmed.