He visited Supelec (Rennes, France) as a doctoral visiting student.

From September to December 2013, Mr. Li visited Supélec (Rennes, France) as a doctoral visiting student. During the visit, he continued the study over the green cellular networks and exchanged thoroughly with the researchers there.

Information on Supélec (Excerpt from the Official Site of Supélec)

The logo of Supelec
The logo of Supelec

Supélec has a very special position among the leading engineering institutes. It is the reference in its field – electric energy and information sciences. Internationally, with classes of 440 engineers graduating each year, Supelec is on a par with the best departments of electrical and computer engineering of the top American or European universities.
More information on Supelec could be found in http://www.supelec.fr/388_p_12054/brief-introduction.html .