Browsing by Author "Chiang, Chin-Te"

Now showing 1 - 3 of 3

Joint Sequence Design for Robust Channel Estimation and PAPR Reduction for MIMO-OFDM Systems
(2013-10-01)
Chiang, Chin-Te
;
Fung, Carrson C.
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A joint superimposed sequence design, known as Superimposed sequence for PAPR Reduction, or SIPR, using per-tone affine pre-coding technique is proposed to jointly estimate MIMO-OFDM channels and reduce the peak-to-average power ratio (PAPR) for MIMO-OFDM systems. The proposed technique optimizes the trade-off between BER, MSE of the channel estimate, and PAPR reduction performance. Moreover, it does not require side information to be transmitted for the removal of the sequence at the receiver, and the transmit redundancy can be as small as 1 symbol/subcarrier. The superimposed sequence is designed by solving a convex quadratically constrained quadratic programming problem and has a computational complexity comparable to previous technique using linear programming. It is shown that SIPR can be regarded as a generalization of the popular tone reservation (TR) technique, and thus, is able to outperform TR in terms PAPR reduction performance, with less transmit overhead. Simulation results and transmit redundancy analysis of SIPR and TR are shown to illustrate the efficacy of the proposed scheme.
Robust Training Sequence Design for Spatially Correlated MIMO Channel Estimation
(2011-09-01)
Chiang, Chin-Te
;
Fung, Carrson C.
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A robust superimposed training sequence design is proposed for spatially correlated multiple-input-multiple-output (MIMO) channel estimation. The proposed scheme does not require accurate knowledge of the spatial correlation matrix, and it is shown to outperform previously proposed robust correlated MIMO channel estimators, such as relaxed minimum mean square error (RMMSE) and least-square RMMSE. Since the training sequence is overlaid into the data stream, the spectral efficiency of the system is higher than those that use time-multiplexed pilots. A solution for the sequence can easily be obtained by using a projection on convex-set-based iterative algorithm that is guaranteed to converge as long as the training sequence matrix is initialized to have full rank. Furthermore, it is shown that the proposed scheme is identical to the RMMSE-based schemes when the MIMO channel is spatially uncorrelated. The computational complexity of the proposed algorithm is also illustrated.
Robust Training Sequence Design for Spatially Correlated MIMO Channel Estimation Using Affine Precoder
(2010)
Chiang, Chin-Te
;
Fung, Carrson C.
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A robust superimposed training sequence design is proposed for spatially correlated MIMO channel estimation. The proposed scheme does not require accurate knowledge about the spatial correlation matrix and it is shown to outperform robust correlated MIMO channel estimators such as relaxed MMSE (RMMSE) and least-squares-RMMSE (LSRMMSE). Since the training sequence is overlaid into the data stream, spectral efficiency of the system is higher than those that use time-multiplex pilots. A solution for the sequence can be obtained easily by using an iterative algorithm which is guaranteed to converge as long as the training sequence matrix is initialized to have full rank.