BT sues Google over Android 'patent infringements'
UK-based telecoms group BT is suing Google in the US over claims that six of its patents have been infringed.
The British company's complaints centre on technologies at the core of Google's Android mobile system, search site, and a wide range of other services.
BT is seeking unspecified damages and an injunction against Google's continued use of its innovations.
The move marks the latest patent attack on Android following legal action by Apple, Microsoft, Oracle and others.
BT said it currently had a portfolio of around 5,600 patents and patent applications.
Its complaint states that it has invested heavily in mobile technologies and related services over the past two decades.
It then claims that its resulting patents have been infringed by Google's search engines, Android system, Google+ social network, eBooks, Maps, Offers, Docs, Places, Gmail, Doubleclick advertising management system, AdWords advertisement listing program and other services.
The six patents involved relate to location-based services, navigation and guidance information and personalised access to services and content.
One example of an alleged infringement is Android's ability to allow a music download if a smartphone is connected to a wi-fi network, but to prevent it when the device only has access to a 3G data link.
Another example is Google Maps ability to make different information available at different levels of zoom.
"BT can confirm that it has commenced legal proceedings against Google by filing a claim with the US District Court of Delaware for patent infringement," a company statement said.
"This is about protecting BT's investment in its intellectual property rights and innovation. It is a well-considered claim and we believe there is a strong case of infringement."
Google said it planned to fight the lawsuit.
"We believe these claims are without merit, and we will defend vigorously against them," a Google spokesman said.
Legal experts say Google's rapid expansion into a wide range of technologies has made lawsuits of this kind all but inevitable.
"There is a lot of money and a huge market in the delivery of mobile phone services and there is a huge battle to achieve marketshare," Vicki Salmon, chair of the UK Chartered Institute of Patent Attorneys (CIPA) told the BBC.
"In amongst this BT may have licensed its technology to some people and is not yet getting the royalties it wants. So there are a lot of battles over who gets what cut out of the market."
A spokesman for BT could not confirm to whom it had licensed its mobile technologies, but noted that the firm had sold patents to third parties in the past.
Consultant, Florian Mueller, has flagged up on his Foss Patent blog that Apple launched a complaint against the Taiwanese Android-device maker HTC five months agousing a "portable computers" patentit bought from BT in 2008.
July's $4.5bn (£2.9bn) sale of Nortel's data networking and other patents highlighted how much value companies attach to these kinds of property rights.
BT would not confirm whether it intended to launch parallel legal action in the European courts. Patent watchers said it may be content to bide its time.
"If they get an injunction against Google in the States, in a sense it's cutting off the Hydra at its head," said Ms Salmon.
"When you are looking at the sale of products sometimes you need to go around country by country and knock out each sale, but if you can knock out the manufacturing base then you don't have to litigate in each country".
BT's previous efforts to defend its patents have not always been successful.
In 2002 a US judge struck down a legal challenge against Prodigy Communications in which BThad claimed to own the patent to internet hyperlinks.
Google's takeover of Motorola Mobility may also complicate matters.
The deal is set to deliver the search giant more than 17,000 patents - potentially providing an opportunity to countersue if it can find an instance where BT has infringed one of Motorola's innovations.