TY - GEN
T1 - Optimized CSI feedback for robust THP design
AU - Castro, Paula M.
AU - Joham, Michael
AU - Castedo, Luis
AU - Utschick, Wolfgang
PY - 2007
Y1 - 2007
N2 - In the broadcast channel (BC), the signals of the multiple users can be separated by means of preceding. For the design of preceding, channel state information (CSI) is necessary at the transmitter side. In many cases (e.g., for frequency division duplex (FDD) systems), the transmitter cannot estimate this information and the CSI has to be communicated from the receivers to the transmitter via a feedback channel that is assumed to be error-free but introduces a delay. Every user estimates the channel and reduces it to a low-dimensional representation for data compression that is possible due to the channel correlations. Before the feedback, the CSI is quantized and only the index of the codebook entry is sent to the transmitter, since the data rate of the feedback channel is limited. We propose a joint MSE optimization of the channel estimation and the rank reduction basis, where the quantizer is modeled as a data independent additive noise source. Based on the fed back codebook index, robust multi-user preceding schemes, viz., linear precoding and Tomlinson Harashima precoding (THP), are designed that clearly outperform non-robust schemes.
AB - In the broadcast channel (BC), the signals of the multiple users can be separated by means of preceding. For the design of preceding, channel state information (CSI) is necessary at the transmitter side. In many cases (e.g., for frequency division duplex (FDD) systems), the transmitter cannot estimate this information and the CSI has to be communicated from the receivers to the transmitter via a feedback channel that is assumed to be error-free but introduces a delay. Every user estimates the channel and reduces it to a low-dimensional representation for data compression that is possible due to the channel correlations. Before the feedback, the CSI is quantized and only the index of the codebook entry is sent to the transmitter, since the data rate of the feedback channel is limited. We propose a joint MSE optimization of the channel estimation and the rank reduction basis, where the quantizer is modeled as a data independent additive noise source. Based on the fed back codebook index, robust multi-user preceding schemes, viz., linear precoding and Tomlinson Harashima precoding (THP), are designed that clearly outperform non-robust schemes.
UR - http://www.scopus.com/inward/record.url?scp=50249142905&partnerID=8YFLogxK
U2 - 10.1109/ACSSC.2007.4487578
DO - 10.1109/ACSSC.2007.4487578
M3 - Conference contribution
AN - SCOPUS:50249142905
SN - 9781424421107
T3 - Conference Record - Asilomar Conference on Signals, Systems and Computers
SP - 1956
EP - 1960
BT - Conference Record of the 41st Asilomar Conference on Signals, Systems and Computers, ACSSC
T2 - 41st Asilomar Conference on Signals, Systems and Computers, ACSSC
Y2 - 4 November 2007 through 7 November 2007
ER -