MIMO-OFDM Beamforming for Improved Channel Estimation

Author

Shen, Cong ; Fitz, Michael P.

Author_Institution

Dept. of Electr. Eng., Univ. of California Los Angeles (UCLA), Los Angeles, CA

Volume

26

Issue

6

fYear

2008

fDate

8/1/2008 12:00:00 AM

Firstpage

948

Lastpage

959

Abstract

The MIMO-OFDM beamforming design problem is addressed from a system level standpoint. A beamforming method is proposed which helps improve the receiver channel estimation performance without degrading any benefit of a conventional beamformer. To that end, the smoothed singular value decomposition (SSVD) algorithm is first developed to get "close" effective channels after beamforming for two adjacent subcarriers. Based on the SSVD algorithm, the frequency smoothed beamformer (FSB) design is then derived, in which smooth effective channels across all subcarriers are generated and thus the receiver can apply interpolation and smoothing to improve the channel estimation performance. The close singular value problem is discussed. Statistical characteristics of the effective channel are analyzed, which is used to design channel estimation for the beamformed channel. Simulation results show that the FSB design is efficient in the IEEE 802.11n setting.

Keywords

MIMO communication; OFDM modulation; channel estimation; interpolation; matrix algebra; wireless LAN; IEEE 802.11; MIMO-OFDM beamforming; frequency smoothed beamformer design; multiple-input multiple-output systems; orthogonal frequency division multiplexing systems; receiver channel estimation; smoothed singular value decomposition algorithm; Array signal processing; Channel estimation; Decoding; Degradation; Frequency estimation; MIMO; OFDM; Signal processing algorithms; Singular value decomposition; Wireless communication;

fLanguage

English

Journal_Title

Selected Areas in Communications, IEEE Journal on

Publisher

ieee

ISSN

0733-8716

Type

jour

DOI

10.1109/JSAC.2008.080811

Filename

4586311