The European Commission has been looking into rebates and financial incentives offered by Qualcomm since 2010 to check if it was using these in breach of EU rules to discourage customers from switching to rivals.
The case was instigated after a complaint from British cellphone chipmaker Icera, a subsidiary of Qualcomm rival Nvidia Corp.
However, the way Qualcomm licenses its patents is not being targeted by the Commission, the source said.
"The Commission is currently not investigating a possible abuse by Qualcomm with regard to the licensing of standard essential patents," said the source, who asked to remain anonymous.
Qualcomm declined to make immediate comment.
The company makes most of its revenues from selling baseband chips, which enable phones to communicate with carrier networks, but a majority of its profit comes from licensing patents for its CDMA cellphone technology.
It paid a $975 million fine to China in February, the largest in that country's corporate history, to end a 14-month investigation. It also agreed to cut its royalty rates on patents used in China and not challenge an antitrust violation finding.
© Thomson Reuters 2015