Article
On Optimum Pilot Design for CombType OFDM Transmission over DoublySelective Channels.
IEEE Transactions on Communications (Impact Factor: 1.75). 01/2011; 59:930935. DOI: 10.1109/TCOMM.2011.020411.100151
Source: DBLP

Conference Paper: Multielement antenna with close spacing for highly mobile OFDM systems
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ABSTRACT: In this paper, we consider employing a multielement antenna (MEA) with close spacing to tackle the challenging channel estimation (CE) in highly mobile OFDM systems. Instead of large spacing for diversity, we propose to place the adjacent elements with one symbol distance in the moving direction to observe the quasiduplicated channels in temporal difference of one symbol period. In exploiting the quasiduplicated channels, we developed a novel CEsymbol detection (SD) iteration that cooperates with the standardized combtype pilots to track fast varying channels. From simulation results, we show the proposed system outperforms the conventional receiver of two antennas with spatial diversity in highly mobile channels as long as the mutual coupling effects with the closespaced elements are restricted.Wireless Communications and Networking Conference (WCNC), 2013 IEEE; 01/2013  [Show abstract] [Hide abstract]
ABSTRACT: Clipping is one of the simplest peaktoaverage power ratio (PAPR) reduction schemes for orthogonal frequency division multiplexing (OFDM). Deliberately clipping the transmission signal degrades system performance, and clipping mitigation is required at the receiver for information restoration. In this work, we acknowledge the sparse nature of the clipping signal and propose a lowcomplexity Bayesian clipping estimation scheme. The proposed scheme utilizes a priori information about the sparsity rate and noise variance for enhanced recovery. At the same time, the proposed scheme is robust against inaccurate estimates of the clipping signal statistics. The undistorted phase property of the clipped signal, as well as the clipping likelihood, is utilized for enhanced reconstruction. Further, motivated by the nature of modern OFDMbased communication systems, we extend our clipping reconstruction approach to multiple antenna receivers, and multiuser OFDM. We also address the problem of channel estimation from pilots contaminated by the clipping distortion. Numerical findings are presented, that depict favourable results for the proposed scheme compared to the established sparse reconstruction schemes.10/2014;  [Show abstract] [Hide abstract]
ABSTRACT: In this paper, we propose three classes of systematic approaches for constructing zero correlation zone (ZCZ) sequence families. In most cases, these approaches are capable of generating sequence families that achieve the upper bounds on the family size (K) and the ZCZ width (T) for a given sequence period (N). Our approaches can produce various binary and polyphase ZCZ families with desired parameters (N,K,T) and alphabet size. They also provide additional tradeoffs amongst the above four system parameters and are less constrained by the alphabet size. Furthermore, the constructed families have nestedlike property that can be either decomposed or combined to constitute smaller or larger ZCZ sequence sets. We make detailed comparisons with related works and present some extended properties. For each approach, we provide examples to numerically illustrate the proposed construction procedure.IEEE Transactions on Information Theory 08/2013; 59(8):49945007. · 2.62 Impact Factor
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