The European Commission has begun an antitrust investigation into mobile technology firm Qualcomm.

Complaints from six manufacturers centre around the licensing of patents that Qualcomm holds on the WCDMA system. The networking system is a component of UMTS, the 3G standard used by mobile carriers for broadband data services.

The complaints allege that Qualcomm abused its market position to charge exorbitant and unfair licensing fees to hardware manufacturers constructing WCDMA chipsets and devices.

Ericsson, Nokia, Texas Instruments, Broadcom, NEC and Panasonic all filed complaints against Qualcomm in 2005.

Patent holders are required under European Union rules to adhere to fair, reasonable and non-discriminatory guidelines when licensing patents to manufacturers.

The complaints prompted a 'preliminary' investigation, which has now been escalated to a 'formal' investigation. The EU has not yet said that Qualcomm violated any rules.

Qualcomm welcomed the move to speed up the proceedings, stating that the complaints are "without merit and are motivated by commercial considerations of the entrenched complainants who are trying to stifle the competition that Qualcomm brings to the market".

"Qualcomm's business model of extensively licensing our innovations has opened WCDMA to new players, driving competition, growth and further innovation, " said Qualcomm president Steve Altmann.

The six manufacturers also praised the decision to hasten the investigation. "We welcome the European Commission's continuation of the investigation into Qualcomm's business conduct," Nokia chief technology officer Tero Ojanperä said in a statement.

"The proper functioning of standardisation requires that companies whose patented technology is adopted into a standard commit to licence those patents on fair, reasonable and non-discriminatory terms."