Prof. Xiang-Gen Xia from the University of Delaware, invited by Prof. YAN Shefeng, delivered an academic report titled "What's Next after OFDM?" in IOA on July 22. More than fifty researchers and students attended it, including CAS Member HOU Chaohuan and Prof. MA Xiaochuan,Vice Director of IOA .

OFDM (Orthogonal Frequency Division Multiplexing) is a modulation scheme widely used in digital wireless communication-4G communication standard. According to the report, communication standard development was mainly determined by the signal bandwidths, so the new modulation scheme with higher signal bandwidths was needed for future communication standards such as 5G standard.

Prof. Xia also presented a new communication method called vector OFDM which selected a vector instead of the single symbol when implementing FFT algorithm in OFDM communication. The method decreased the rate loss that was proportional to the vector dimension, and just introduced slightly ISI. Moreover, the method treated OFDM and single carrier systems as two extreme cases and balanced a good tradeoff among bandwidth, OFDM symbol length, cyclic prefix length and complexity.

Besides digital wireless communication, Xia provided an effective roadmap solution for underwater acoustic communication, which aroused broad interests from the acoustic communication researchers.

Xia is a Fellow of the IEEE and received the Outstanding Overseas Young Investigator Award from the National Nature Science Foundation of China in 2001. For more information about him, please visit: http://www.eecis.udel.edu/~xxia/

Prof. Xiang-Gen Xia