The US International Trade Commission has determined that Qualcomm is infringing on one of Broadcom's patents, dealing a blow to Qualcomm in an ongoing patent battle between the companies.

The Commission hasn't yet issued a penalty for the infringement and Qualcomm said it would appeal. The companies are in the midst of a number of other lawsuits with each other regarding mobile phone patents.

Broadcom said the Commission could bar Qualcomm from importing its chips to the US, forbid Qualcomm from selling the infringing products in the US and even ban the import of phones containing the chips.

But Qualcomm says that the Administrative Law Judge, who made the initial ruling that was upheld by the Commission, has recommended against barring the import of phones that use the chips. The Commission made its ruling on Friday and both Qualcomm and Broadcom released statements on Monday. The Commission will issue its remedy decision by 9 February.

Qualcomm has downplayed the importance of the technology in question, saying it is based on software and not fundamental to CDMA, the mobile technology that Qualcomm created and is best known for. Qualcomm has said previously that it is exploring ways to work around the technology.

The two companies have several other outstanding cases against each other. One is set to be tried in March, another in May, and a third doesn't yet have a trial date set. Broadcom is also appealing an anti-trust suit that it filed against Qualcomm which has been dismissed.

Broadcom is also one of five technology companies that filed anti-competitive complaints against Qualcomm with the European Commission.