Overview: The annual International Conference on Wireless Communications and Signal Processing (WCSP) aims to provide a forum that brings together International researchers from academia and practitioners in industry to meet and exchange ideas and recent research work on all aspects of wireless communications and signal processing. Following the great success of WCSP’09, WCSP’10, and WCSP’11, the fourth edition of the event, WCSP’12, will be held in Huangshan (Yellow Mountain), Anhui Province, China, on October 25-27, 2012, and will be sponsored by the National Mobile Communications Research Lab at Southeast University, China, and technically sponsored by IEEE Communications Society.  The conference will consist of keynote speeches, technical sessions, and workshops. The technical sessions will present original and fundamental research advances, and the workshops will focus on hot topics in wireless communications and signal processing.