Samsung signed an agreement with Qualcomm not to sue the chip maker or its customers for using Samsung's 3G patents, but this agreement was called off when Apple took Samsung to court over the Galaxy Tab, Samsung admitted in the Australian Federal Court this morning.

The Federal Court today commenced the long-awaited case between Apple and Samsung over alleged patent infringements by the two companies. The court began hearing Samsung's counter-claim against Apple — that the company infringed on three standards-essential 3G patents held by Samsung in the iPhone 4, iPhone 4S and iPad 2.

Samsung counsel Neil Young today admitted that Qualcomm, which supplies chips to Apple, had an agreement with Samsung whereby the Korean tech giant would not sue Qualcomm or its customers for infringement on 3G patents. According to court documents, this agreement was first made back in 1993.

"There was an agreement between Samsung and Qualcomm. That agreement was not a licence agreement. It contains a contractual provision that Samsung would not sue Qualcomm or customers of Qualcomm who apply [the 3G patents]," Young said.

Samsung stated that this agreement was terminated in April 2011, with notice provided to Qualcomm, when Apple first filed proceedings against the Galaxy Tab in California.

At that point, Apple sought a licence to use Samsung's UMTS patents in its devices, and Samsung's counsel argued that the company offered a "fair commercial rate" to license the products under fair, reasonable and non-discriminatory (FRAND) terms. Samsung stated that Apple rejected this proposal, and refused to enter further negotiations to obtain a licence.

"Samsung has done nothing other than take steps to protect its patent rights against infringement in the same way in it would in the ordinary course in circumstances where it has been sued by Apple, and Apple has refused to enter negotiations for the UMTS patent," Samsung's counsel said.

Samsung stated that Apple's argument is that Samsung's willingness to license the patents means that the patents are automatically licensed under European Telecommunications Standards Institute (ETSI) laws — and, as Australia is an associate member of the institute, these rules should apply here. Samsung will argue that this is not the case, relying on expert testimony from a French professor, as well as Australian legal experts.

Samsung initially sought to prove that Apple had infringed on seven patents, but has now settled on the following three patents as part of its case:

Australian Patent number 2005239657: "method and apparatus for transmitting and receiving data with high reliability in a mobile communication system supporting packet data transmission"

Australian Patent number 2005202512: "method and apparatus for data transmission in a mobile telecommunication system supporting enhanced uplink service"

Australian Patent number 2006241621: "method and apparatus for transmitting/receiving packet data using predefined length indicator in a mobile communication system".

The first week of the case will focus on the latter two patents, while the hearings beginning on 6 August will initially focus on the first patent.