Qualcomm facing an anti-trust lawsuit and two patent infringement lawsuits from Broadcom, has filed its own patent suit against Broadcom.

Qualcomm, a cell-phone chip maker, accuses Broadcom of using technology covered by seven of its patents without permission. The lawsuit, filed in the US District Court for the Southern District of California in San Diego, accuses Broadcom of infringing six of Qualcomm's patents related to integrated circuits for use in GSM phones and infringing a seventh patent related to semiconductor chips for Wi-Fi devices.

In May, Broadcom filed two lawsuits against Qualcomm, accusing it of infringing 10 patents. Broadcom also filed an anti-trust lawsuit against Qualcomm this month, accusing Qualcomm of engaging in unfair licensing practices for its CDMA technology, resulting in higher priced cell phones in the US. Broadcom said it was filing the suit to prevent the same situation occurring in the developing 3G cell-phone market.

Many GSM wireless carriers have deployed a form of CDMA, called WCDMA (wideband CDMA), for some 3G services related to multimedia distribution, higher data transmission rates and other improvements.

In the two May lawsuits, Broadcom focuses on a variety of technologies for multimedia mobile phones, including QChat, digital video encoding and decoding, simultaneous voice and data transmission and the use of Bluetooth. Broadcom also filed a complaint about Qualcomm with the International Trade Commission in May.

Qualcomm said the GSM-related infringements focus on features added to GSM capabilities that Qualcomm has pioneered in CDMA wireless devices.

"Those who believe that Qualcomm's intellectual property portfolio is limited to CDMA have overlooked the breadth of our business activity and the extent of our research and development from which our intellectual property is generated," Louis M. Lupin, Qualcomm's senior vice president and general counsel, said in a statement. "Our intellectual property rights are broad, and we will not hesitate to assert their full breadth when appropriate."

Qualcomm sued Broadcom primarily to protect its intellectual property, not as a reaction to the Broadcom lawsuits, Qualcomm spokeswoman Emily Gin Kilpatrick said.

Qualcomm would have preferred to resolve the companies' patent claims through negotiations, but Broadcom filed suit, she said.

Broadcom dismissed Qualcomm's lawsuit as a response to its May patent infringement suits.

"It is very common for defendants in patent cases to respond with countersuits," Broadcom said. "We filed our patent lawsuits on the strength of our conviction that we have a very strong case, and we remain confident of prevailing in the courts. We will not be deterred by Qualcomm’s counterclaims."