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In-Band Full Duplex for Wireless Communications – From Echo Cancellation to Self-Interference Cancellation
Date: 2014/5/23             Browse: 1169

Speaker: Dr. Fuyun Ling

Time: 5/23, Friday, 3:30 to 4:30

Location: Room 220, Building 8


In-Band Full-Duplex (IBFD) for wireless communications has attracted quite some interest in the wireless communication field.  The IBFD technology utilizes transmitter/receiver signals isolation and self-interference cancellation to achieve full duplex communication in the same band at the same time.  Thus, it has the potential to double spectrum efficiency for applications under proper circumstances.

While it is relatively new in the wireless communications area, similar technologies has been considered and utilized in Radar and wireline communications.  In particular, self-interference cancellation is closely related to echo cancellation technology employed in commercial products of wireline communications over past thirty years.  What learned from the development and implementation of echo-cancellation modems can provide valuable insight and guidance to the applications and implementation of IBFD for wireless.

In this talk, we first provide an overview of the IBFD technology for wireless communications.  Its origins, operation principles and basic building blocks are presented.  Secondly, we examine one of its key blocks, i.e., self-interference canceller (SIC) and compare it is with the well-studied echo canceller.  Their similarities and differences are discussed.  Specifically, we discussed the structure, design, characteristics and implementation considerations of such cancellers.  Moreover, since wireless channels are time-varying by nature, we analyzed the impact of time variation to SIC’s performance by establishing a novel linearized model of such cancellers employing LMS adaptive algorithm.  Based on these results, various factors that impact the overall performance of SIC are summarized; possible applications and limitations of IFBD are considered.  We conclude this presentation by proposing possible research topics on this subject and providing final remarks.


Fuyun Ling received his B. S. degree from Tsinghua University, Beijing, China, in 1968, and his MS and Ph. D. degrees from Northeastern University, Boston, Mass., USA, in 1981 and 1984, respectively.

From 1984 to 1998, he was with Motorola Inc. working on research and development of various wireline and wireless communication technologies and products.  In 1998, he joined Qualcomm Incorporated, San Diego, California, as a Vice President of Technology and worked on research and development of new wireless communication technologies.  Since 2003 to 2010, he worked on MediaFLO Mobile TV project responsible for its specification and its system and product development.  From late 2010 to middle of 2012, He worked with various Qualcomm engineering groups on new technology developments.  Dr. Ling retired from Qualcomm in June 2012 and now is an independent consultant in his newly founded company Twinclouds Consulting, LLC.  He is actively involved in consulting and publishing tutorial materials online in the digital communication and digital signal processing areas.

Throughout his career, Dr. Ling has been working on digital communications and digital signal processing and their application to wireless and wire-line communications.  He holds over 120 US Patents with a number of other patent applications pending.  He has also published over 80 papers and co-authored two books all in his technical areas.  He held Adjunct Professor positions at Northeastern University (1987-1995) and Tsinghua University (2002-2008, 2014- ).  Dr. Ling is a Life Fellow of IEEE.

                                                                                                                            SIST-Seminar 14016