As the smartphone market continues to expand, a clear leader has failed to emerge. With multiple OS platform's like Ios, Android, WP7, webOS, Symbian and MeeGo vying for space, the intense fight for market share has resulted in companies resorting to acquiring patents as a preemptive tool or charging each other with patent lawsuits to seek permanent injunction to protect their turf. Also in the game are patent trolls that are seeking to milk the nervous but growing smartphone industry.

Here is a chronology of the major patent lawsuits and agreements filed in the year 2010 in the smartphone industry:

January 14 - Eastman Kodak files patent infringement lawsuits against Apple and BlackBerry maker RIM, relating to technology used in their phones' camera to preview images. It also charges Apple of using its technology that enables one application to call another app to complete functions.

Jan. 25 - Motorola files a complaint against BlackBerry maker RIM claiming infringement of five patents related to features such as Wi-Fi access, application management, UI and power management.

Feb. 10 - Israeli technology company Emblaze files a patent infringement case against Apple and Microsoft alleging them of infringing on its media streaming technology patent. Apple uses the technology on its iPhone, iPod Touch and iPad while Microsoft uses it in its Silverlight software.

March 2 - Apple sues Taiwanese phone maker HTC for infringing on 20 of its patents related to iPhone's UI, underlying architecture and hardware design.

March 10 - SmartPhone Technologies LLC, files patent infringement case against Apple, AT&T, LG, Motorola, and Research in Motion (RIM), Samsung and Sanyo. The patent infringement relates to Bluetooth connectivity and email synchronization.

March 16 - A company called MicroUnity sues 22 companies, including the likes of Apple, AT&T, Google, HTC, LG, Motorola, Nokia, Palm, Qualcomm, Samsung, Sprint Nextel, and Texas Instruments. It alleged infringement of 14 patents related to a variety of mobile-processor technologies.

April 28 - Microsoft announces patent agreement with HTC Corp. that grants it broad coverage under Microsoft's patents portfolio, for HTC devices running Google's Android.

May 7 - Nokia files patent infringement lawsuit against Apple, alleging it of infringing five patents covering speech codecs, data transfer and use of location information which are used in iPhone and iPads.

May 13 - HTC sues Apple for infringement of five of its patents.

June 23 - Apple extends the number of patent infringement charges against HTC, adding two more patents to the list related to system for real-time adaptation to changes in display configuration.

July 9 - Patent holding firm NTP sues Apple, Google, HTC, LG, Microsoft and Motorola for IP infringement related to eight patents covering wireless email delivery technology.

Aug. 12 - Oracle sues Google charging it with knowingly infringing on Oracle's Java related property. At the root of the issue is Google's Android which includes a Java-compatible technology Dalvik, a virtual machine.

Sept 16 - Skyhook Wireless, a company that develops technology to locate a mobile phone's location using Wi-Fi signals, sues Google for anti-competitive practices and patent infringement related four patents covering location services.

Sept. 28 - Apple sues Nokia in a U.K. court citing the same nine patents it had accused Nokia of infringing in US.

Oct. 1 - Microsoft sues Motorola charging it with infringing on nine of its patents related to development of Android-based phones. The patent infringement pertains to categories related to email synchronization, calendar and contacts, scheduling meetings and applications that alert users about battery and signal status.

Oct. 6 - Motorola sues Apple for patent infringement related to 18 patents covering wireless communication technologies, antenna design, wireless email, proximity sensing, software application management, location-based services and multi-device synchronization.

Oct. 7 - Microsoft licenses 74 patents related to smart phones from Acacia Research Corp for an undisclosed sum. The patents cover inventions created by Access, Palm, Palmsource, Bell Communications Research, and Geoworks.

Oct. 25 -- Gemalto, a digital security provider, has filed a patent infringement case against Google, Samsung, Motorola and HTC. It alleges that Google used its Java Card Technology, which allows applications developed in Java to be executed in resource limited devices, in development of applications built on Android and in running its Dalvik virtual machine.

Oct. 29 -- SmartPhone Technologies LLC, sues HTC, Exedea, Nokia, Sony Ericsson, and Kyocera for infringement of 8 patents.

Oct. 31 - Apple sues Motorola for infringing six patents related to multitouch and OS.

Nov. 10 - Microsoft sues Motorola for refusing to license patents on Frand terms.

Nov. 11 -- Motorola countersues Microsoft for infringing on 16 patents. It stated that Microsoft infringes with its PC and server software, Windows mobile software, and Xbox products.

Nov. 23 -- Motorola complains to International Trade Commission (ITC) that Microsoft imports Xbox kits which infringe on its patents and thus should be banned in US.

Nov. 23 - HTC enters into a licensing deal with Intellectual Ventures, an outfit run by Nathan Myhrvold, which gives it access to a portfolio of 30,000 IP assets.

Dec. 16 -- Nokia sues Apple in Britain, Germany and Netherlands for infringing on 13 patents which includes a wiping gesture used to maneuver on a smartphone touchscreen.

Dec. 23 - Motorola extends its patent lawsuit against Microsoft to include two new patents which covers Kinect motion controller technology. Microsoft in response added seven new patents to its claims which include Motorola's DVR boxes technology along with Android infringements.