Doppler-assisted Channel Estimation and Parallel Interference Cancellation for High Mobility MIMO-OFDM Systems
Neda Aboutorab (ANU)
APPLIED SIGNAL PROCESSING SERIESDATE: 2012-08-23
TIME: 10:00:00 - 11:00:00
LOCATION: RSISE Seminar Room, ground floor, building 115, cnr. North and Daley Roads, ANU
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ABSTRACT:
To achieve very high data rates, multiple-inputa"multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) techniques have been adopted in the Third-Generation Partnership Project Long-Term Evolution (3GPP LTE) and Worldwide Interoperability for Microwave Access (WiMAX) standards. MIMO-OFDM symbol detection in these standards requires channel state information (CSI) estimation at the receiver, where the reliability of symbol detection depends on the accuracy of this channel estimation. In this talk, an iterative channel estimation and inter-carrier interference (ICI) cancellation method will be proposed for highly mobile users in LTE systems. The proposed scheme estimates the wireless channel by using pilot symbols, estimates of the data symbols, and Doppler spread information at the receiver. The wireless channel is expressed by weighted time-domain channel interpolation, where the interpolation weights are designed based on the Doppler spread and time-domain channel correlations. The channel estimates are obtained by employing a least-square (LS) method. A simplified parallel interference cancellation (PIC) scheme coupled with decision statistical combining (DSC) is used to cancel the ICI and to improve data symbol detection. These data symbols are then utilized to further refine the channel estimation, iteratively. The simulation results show that the performance degradation of the proposed iterative channel estimation and ICI cancellation scheme in a high-mobility environment, compared with the performance of a system when users are static and perfect channel state information (CSI) is available at the receiver, is minimal.
BIO:
Neda is a Research Fellow in the ASP group.
