Linear Precoding and Iterative MMSE Dectection and Eigen-Direction Alignment Aided Physical-Layer Network Coding, for MIMO Channels

Dr. Xiaojun YUAN
City University of Hong Kong
Wednesday, 9 March, 2011
10:00 -11 :00 am
Room 833, Ho Sin Hang Engineering Building The Chinese University of Hong Kong

Part I: Linear Precoding and Iterative MMSE Detection for MIMO Channels with and without CSIT
We consider efficient  transmission over multiple-input multiple-output (MIMO) channels. Our proposed scheme involves linear-precoding (LP) at the transmitter and iterative linear minimum mean-square error (ILMMSE) detection at the receiver. We establish an area theorem to evaluate the achievable rate of the proposed scheme. We show that, in the case of perfect channel state information at transmitter (CSIT), a properly designed LP-ILMMSE scheme can achieve the water-filling capacities of MIMO channels. We also show that, in the  case of no CSIT, the proposed scheme can perform close to the outage channel capacity.
Part II: Eigen-Direction Alignment Aided Physical-Layer Network Coding for MIMO Two-Way Relay Channels
We propose a joint channel coding and physical layer network coding (CPNC) scheme for multiple-input multiple-output (MIMO) two-way relay channels (TWRCs). At the heart of the scheme lies a key technique referred to as eigen-direction alignment (EDA) precoding. This technique efficiently creates multiple aligned parallel channels, which facilitates the deployment of multi-stream CPNC. Our analysis shows that the achievable rate of the scheme can approach the capacity upper bound in the median to high signal-tonoise (SNR) region when nT > nR, where nT and nR denote the number of antennas of each user and that of relay, respectively. The gap to the capacity upper bound diminishes as nT/nR increases. Numerical results demonstrate that the proposed scheme tremendously outperforms other existing schemes.


Dr. Yuan received the B.S. degree in electronic and information systems from Shanghai Jiaotong University in 2000, the M.S. degree in circuit and systems from Fudan University in 2003, and the Ph.D. degree in electrical engineering from the City University of Hong Kong in 2008. Since 2009, he has been a research fellow at the Department of Electronic Engineering, the City University of Hong Kong. During 2009.2-2009.8 and 2010.1-2010.7, he was working as a visiting scholar at the University of Hawaii at Manoa. His research interests include coding and coded modulation techniques, multiple-input multiple-output (MIMO) and orthogonal frequency-division multiplexing (OFDM) systems, and network information theory. He has published about 30 refereed papers in the world-leading journals and conferences in the related areas. He is now a member of IEEE.