Qualcomm, which has filed several patent infringement and patent royalty lawsuits against Apple since July, is now being countersued by Apple over alleged patent infringements involving Qualcomm's Snapdragon mobile phone chipsets.

The latest legal salvo came as part of a revised court filing by Apple in response to Qualcomm's earlier legal claims, according to a Nov. 29 story by Reuters. Apple's countersuit claims the Qualcomm Snapdragon chipsets used in Android mobile phones and other devices infringes on Apple's patents.

In a legal filing in U.S. District Court in San Diego, Apple on Nov. 29 alleged "it owns at least eight battery life patents that Qualcomm has violated," the story reported. "The Apple patents involve ensuring each part of a phone's processor draws only the minimum power needed, turning off parts of the processor when they are not needed and making sleep and wake functions work better."

Apple claims in its filing that the Qualcomm Snapdragon 800 and 820 processors, which are used in Samsung mobile phones and Google Pixel phones, infringe on those patents, the story continued.

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This latest action comes some 11 months after Apple sued Qualcomm for $1 billion in January over its patent licensing practices, claiming that the chip maker is using its "monopoly" position in baseband chips—a key component in mobile phones and other wireless devices—to charge costly fees and royalties and practicing "exclusionary tactics" in the market.

In response, Qualcomm in July asked the International Trade Commission (ITC) toban imports of some Apple iPhonesthat officials said infringe on multiple Qualcomm patents that drive performance and battery life of the devices.

Earlier in November, Apple reportedly began considering options to eliminate Qualcomm modem parts from future iPhone and iPad models, weeks after Qualcomm filed additional lawsuits in China that sought to ban sales of the latest iPhones due to alleged patent infringement in the newly released devices.

The move could mean that Apple will use modem parts from Intel or MediaTekfor its mobile devices. About half of today's iPhones use Qualcomm modem chips, while the other half use chips from Intel.

In October, Qualcomm filed several patent lawsuits in China against Apple demanding licensing fees for several mobile technologies that the chip producer claims are built into iPhones. The lawsuit asks China's courts to ban iPhone sales in that nation as it pursues compensation from Apple for the alleged patent infringement.