ABSTRACT: This paper deals with the design and performance analysis of transmit precoder optimization for multiple input multiple output
(MIMO) systems with limited feedback of channel state information. A capacity criterion based optimal codebook construction
algorithm for MIMO precoded spatial multiplexing systems is presented. The optimal precoder structure combining precoding
and power allocation is employed. Simulation results show that the capacity criteria based codebook can achieve higher capacity
than that of equally power allocation based codebook of previous research.
Journal of Shanghai Jiaotong University (Science) 04/2012; 14(2):215-218.
ABSTRACT: This paper deals with design and analysis of user scheduling and power allocation for multi-antenna OFDM systems with DPC,
ZF-DPC, ZF-BF and TDMA transmit strategies. We consider the general multi-user downlink scheduling problem and power minimization
with multi-user rate constraints. According to the channel state, it is shown that there is a power optimal policy which selects
a subset of users in each scheduling interval. We present user selection algorithms for DPC, ZF-DPC, ZF-BF and TDMA for multi-antenna
OFDM system in broadcast channels, and we also present the practical water-filling solution in this paper. By the selected
users with the consideration of fairness, we derive the power optimization algorithm with multi-user rate constraints. We
also analyze the power duality of uplink-downlink for the transmit strategies of DPC, ZF-DPC and ZF-BF. Simulation results
show that the present user-scheduling algorithm and power minimization algorithm can achieve good power performance, and that
the scheduling algorithm can guarantee fairness.
Journal of Zhejiang University - Science A: Applied Physics & Engineering 01/2008; 9(2):215-224. · 0.41 Impact Factor
ABSTRACT: This paper deals with the design and performance analysis of the transmission precoder optimization for multiple-input multiple-output
(MIMO) systems with limited feedback of channel state information (CSI). We assume that the receiver can get perfect channel
knowledge by channel estimation while the transmitter only has partial channel knowledge from limited feedback. We present
a minimum mean square error (MMSE) criterion based codebook construction algorithm for MIMO precoded spatial multiplexing
systems under a specific average power constraint. The optimal transmitter structure is employed in this paper. Simulation
results show that the MMSE criteria based codebook construction algorithm with hybrid design of power allocation and precoding
can achieve better performance than that of equal power allocation based codebook of previous research.
Journal of Zhejiang University - Science A: Applied Physics & Engineering 10/2007; 8(12):1894-1900. · 0.41 Impact Factor
ABSTRACT: A space-time coded multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) system is considered
as a solution to the future wideband wireless communication system. This paper proposes an extended Kalman filtering-based
(EKF-based) channel estimation method for space-time coded MIMO-OFDM systems. The proposed method can exploit pilot symbols
and an extended Kalman filter to estimate channel without any prior knowledge of channel statistics. In comparison with the
least square (LS) and the least mean square (LMS) methods, the EKF-based approach has a better performance in theory. Computer
simulations demonstrate the proposed method outperforms the LS and LMS methods. Therefore it can offer dramatic system performance
improvement at a modest cost of computational complexity.
Journal of Shanghai University (English Edition) 01/2007; 11(5):469-473.
ABSTRACT: Considering that channel estimation plays a crucial role in coherent detection, this paper addresses a method of Recursive-least-squares
(RLS) channel estimation with adaptive forgetting factor in wireless space-time coded multiple-input and multiple-output orthogonal
frequency division multiplexing (MIMO-OFDM) systems. Because there are three different forgetting factor scenarios including
adaptive, two-step and conventional ones applied to RLS channel estimation, this paper describes the principle of RLS channel
estimation and analyzes the impact of different forgetting factor scenarios on the performances of RLS channel estimation.
Simulation results proved that the RLS algorithm with adaptive forgetting factor (RLS-A) outperformed that with two-step forgetting
factor (RLS-T) or with conventional forgetting factor (RLS-C) in both estimation accuracy and robustness over the multiple-input
multiple-output (MIMO) channel, i.e., a wide-sense stationary uncorrelated scattering (WSSUS) and frequency-selective slowly
fading channel. Hence, we can employ the RLS-A method by adjusting forgetting factor adaptively to track and estimate channel
state parameters successfully in space-time coded MIMO-OFDM systems.
Journal of Zhejiang University - Science A: Applied Physics & Engineering 03/2006; 7(4):507-515. · 0.41 Impact Factor