This talk is concerned with an uplink scheme for multi-cell large antenna systems. We study a channel estimation technique where partially decoded data is used to estimate the channel. We show that there are two types of interference components in this scheme that do not vanish even when the number of antennas grows to infinity. The first type, referred to as cross-contamination, is due to the correlation among the data signals from different users. The second type, referred to as self-contamination, is due to the dependency between the channel estimate and the estimation error. Cross contamination is in principle similar to pilot contamination in a conventional pilot-based channel estimation scheme, while self-contamination is unique for the data-aided scheme. For spectral efficient, the data part in a signaling frame is typically much longer than the pilot part for a practical system. Consequently, compared with pilot signals, data signals naturally have lower cross correlation. This fact reduces the cross-contamination effect in the data-aided scheme. Furthermore, self-contamination can be effectively suppressed by iterative processing. These results are confirmed by both analyses and simulations.
Prof. Li Ping received his Ph.D. degree at Glasgow University in 1990. He lectured at Department of Electronic Engineering, Melbourne University, from 1990 to 1992, and worked as a research staff at Telecom Australia Research Laboratories from 1993 to 1995. Since January 1996, he has been with the Department of Electronic Engineering, City University of Hong Kong, where he is now a professor of information engineering. Prof. Li Ping received the IEE J J Thomson premium in 1993, the Croucher Foundation Award in 2005 and a British Royal Academy of Engineering Distinguished Visiting Fellowship in 2010. He served as a member of the Board of Governors for IEEE Information Theory Society from 2010 to 2012 and he is a fellow of IEEE.