China's anti-monopoly regulator has suspended its investigation of InterDigital Inc after the US wireless technology patent developer pledged to change its pricing structure, but the National Development and Reform Commission (NDRC) said it would resume the probe if the company did not follow through.

The NDRC said in a statement on Thursday that Delaware-based InterDigital cooperated with the investigation which was launched in June.

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InterDigital, also known as IDC, in March requested the investigation be suspended, saying it would take "specific steps to eliminate the consequences of (its) suspected monopolistic behaviour."

The steps included not charging Chinese companies "discriminatory" high-priced licensing fees, not bundling licenses for non-standard essential patents and standard essential patents, and not litigating to force Chinese companies accept "unreasonable" license conditions.

"We feel that these commitments are sufficient to eliminate the consequences of the alleged monopolistic behaviour, to ensure equitable participation of Chinese companies in market competition and to restore competitive order to the market," Xu Kunlin, Director General of the NDRC's Department of Price Supervision, told an antitrust conference on Thursday in Beijing.

"Of course, we will monitor the implementation of these commitments and if they are not well executed we will resume the investigation according to law."

InterDigital's US-based vice president for communications could not be reached for immediate comment.

The NDRC has been stepping up its anti-monopoly enforcement in the past year. The agency handed down record fines to six milk powder companies, including Mead Johnson Nutrition Co and Danone SA.

It is currently investigating Qualcomm Inc, another large US patent holder and the world's biggest cellphone chip maker. Qualcomm faces the prospect of a record fine exceeding $1 billion.

Qualcomm is in communication with the NDRC regarding the investigation, Xu said at the conference.