Dong-Jo Park

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This study introduces a new method for precise timing estimation in OFDM systems. In multipath channels, conventional correlation-based methods experience performance degradation due to channel dispersion. Based on a symmetric correlation property of a preamble, the proposed method is developed to exploit statistical change of a symmetric correlator in the(More)
We design pilot-symbol-assisted modulation for carrier frequency offset (CFO) and channel estimation in orthogonal frequency-division multiplexing transmissions over multi-input multi-output frequency-selective fading channels. The CFO and channel-estimation tasks rely on null-subcarrier and nonzero pilot symbols that we insert and hop from block to block.(More)
A critical issue in applications involving networks of wireless sensors is their ability to synchronize, and mitigate the fading propagation channel effects. Especially when distributed “slave” sensors (nodes) reach-back to communicate with the “master” sensor (gateway), low power cooperative schemes are well motivated. Viewing(More)
An efficient algorithm for image segmentation based on a multi-resolution application of a wavelets transform and feature distribution is presented. The original feature space is transformed into a lower resolution with a wavelets transform to derive fast computation of the optimum threshold value in a feature space. Based on this lower resolution version(More)
We present an efficient video segmentation and tracking strategy based on edge information to assist object-based video coding, motion estimation, and motion compensation for MPEG-4 and MPEG-7. The proposed algorithm utilizes the human visual perception to provide edge information. Three parameters are introduced and described based on edge information from(More)
In MIMO wireless communications, spatial multiplexing can be employed to achieve a high data rate. However, its performance can be degraded by spatial correlation between the transmit antennae. Hence, a simple closed-form linear precoder is proposed to improve performance when two transmit antennae are exploited at the transmitter. The proposed precoder(More)
We design pilot symbol assisted modulation for carrier frequency offset (CFO) and channel estimation in orthogonal frequency division multiplexing (OFDM) transmissions over multi-input multi-output (MIMO) frequency-selective fading channels. By separating CFO and channel estimation from symbol detection, the novel training patterns lead to low-complexity(More)
The conventional pilot-aided orthogonal frequency division multiplexing (OFDM) systems use the fixed number of pilots to estimate the channel. In this paper, we propose a new channel estimation scheme that exploits reliable decisionfeedback symbols in the OFDM systems. The reliable symbols having low symbol error rate can be used to refine the channel(More)