Nokia said Tuesday that the US International Trade Commission would begin investigating its claims of unfair business practices and patent infringement against Qualcomm. The cellular phone maker said there is significant evidence that Qualcomm has used its technology in both GSM and CDMA chips, and filed a complaint with the ITC on August 16. It is seeking to have the offending chips banned from importation.

The two sides have been locked in a legal tit-for-tat since April of this year, when a patent licensing agreement between the two expired. In this case, the patents have to do with technologies that improve the performance and efficacy of wireless communications. This enhancements result in lower manufacturing costs, better battery life, and make it possible to develop smaller phones.