HTC has decided to up the ante in its smartphone patent tussle with Apple. The company has filed a patent infringement lawsuit against Apple in Delaware, accusing Apple of infringing three of its patents with nearly every product Apple makes. HTC may be hoping this suit will give it some leverage with Apple, which currently has four patent infringement lawsuits and two International Trade Commission complaints pending against the Tawainese smartphone maker.

Apple warned smartphone makers in 2009 and again in 2010 that it "will not stand for having [its] IP ripped off." The company made good on those threats when it first sued HTC in March 2010, launching two federal patent infringement suits and one parallel ITC complaint that involved 20 separate patents.

The patent charges were seen as a proxy fight against Android, as Apple has also targeted Motorola and Samsung with lawsuits that involved at least some software-related patents, but it hasn't gone after Google directly. (Google announced plans to acquire Motorola yesterday.) For its part, HTC said it was ready to fight with a patent portfolio of its own.

But things haven't gone so well for HTC so far. In April, the company made a licensing deal with Microsoft to avoid patent litigation with that company over Android. HTC finally responded to Apple with an ITC complaint of its own in May, but Apple responded right back in June with an additional patent infringement lawsuit citing four additional patents. Then, in July of this year, Apple piled on four more patents in a new lawsuit and an ITC complaint which targeted newer HTC products.

Then came down an initial determination from an ITC administrative law judge that HTC infringed two of Apple's patents from the original complaint filed in March 2010. That decision is still pending final review. If it goes Apple's way, though, the company could have a potential weapon against any Android vendor—at least one of the patents is believed to be related to the Android operating system itself.

HTC may have thought that it finally had something on Apple when it acquired S3 Graphics just days after an initial determination by the ITC that Apple infringed two of its graphics-related patents. However, additional information that was released at the end of July revealed that the case involved Mac OS X, and not iOS or the iPhone. Furthermore, the claims of the two patents in question that Mac OS X supposedly infringed had recently been ruled invalid by the US Patent and Trademark Office, giving Apple a clear reason to have the initial determination overturned by an ITC review panel.

HTC's latest offensive includes claims that all of Apple's mobile devices, including the iPhone, iPod touch, and iPad infringe on a patent for integrating a PDA with wireless communications. It's hard to say if Apple's products infringe the patent's claims or not, as the patent describes a specific arrangement of two simultaneous serial port connections between a PDA device and its integrated "wireless communication system." Essentially, if the A4 processor connects to the baseband processor using two serial connections that simultaneously transmit certain information and digital audio signals, it's possible Apple could be found infringing on this patent.

The other two patents in question involve wireless communication methods and seem to relate to Apple's implementation of WiFi, as HTC's complaint alleges that all of Apple's computers and mobile devices infringe on these two patents. Most curiously, both patents were originally assigned to ADC Telecommunications, a Minnesota company that was recently acquired by Switzerland-based Tyco Electronics. As HTC claims to now own these patents, it appears it went shopping for some ammunition against Apple as its own portfolio proved not to be as strong as it originally thought.

Even if HTC's patents do apply to Apple's products, this fight still seems heavily weighted in Apple's favor. With a potentially big ITC win under its belt and at least 28 patents asserted to HTC's handful, these three new patents may not give HTC much of a negotiating position.