Thu, 07 Aug 2008 21:53:35 BST CiteULike: dcastro's accuracy http://www.citeulike.org/user/dcastro/tag/accuracy CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dcastro/article/2883761 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 54, No. 4. (2006), pp. 1865-1875.</i><br /><br />The Cramer-Rao lower bound (CRLB) was determined for different ultra-wideband (UWB) signal formats and, in particular, for the two UWB high-data-rate (HDR) signal formats proposed within the IEEE 802.15.3a Task Group, that is, the impulsive direct-sequence UWB (DS-UWB) and the nonimpulsive multiband orthogonal frequency-division multiplexing (MB-OFDM), and an impulsive time hopping (TH) UWB format close to the format for UWB low data rate (LDR) of the forthcoming IEEE 802.15.4a standard. The analysis was carried out for both ideal and multipath channels under power constraints as set by emission masks. Results obtained for HDR formats showed that DS-UWB has better ranging accuracy than does MB-OFDM, thanks to its potentially larger bandwidth and higher frequency of operation. In addition, the degree of multipath strongly affected ranging accuracy, although differently for DS-UWB versus MB-OFDM. When incorporating a correlation receiver structure as well as an Early Late gate synchronizer in the model, ranging performance proved to be related to features of the synchronization sequence. For specific synchronization sequences, in particular, the best ranging accuracy was obtained with MB-OFDM. In the case of LDR, the study analyzed the effect of pulse shape on CRLB. Results showed that a suboptimal choice of the pulse shape reduces the ranging accuracy achievable by TH-UWB signals. UWB ranging accuracy in high- and low-data-rate applications R Cardinali L De Nardis MG Di Benedetto P Lombardo doi:10.1109/TMTT.2006.871993 Microwave Theory and Techniques, IEEE Transactions on, Vol. 54, No. 4. (2006), pp. 1865-1875. 2008-06-11T20:26:45-00:00 2006 Microwave Theory and Techniques, IEEE Transactions on 54 4 1865 1875 accuracy ranging uwb http://www.citeulike.org/user/dcastro/article/2425863 <i>Wireless Communications, IEEE Transactions on, Vol. 4, No. 1. (2005), pp. 228-237.</i><br /><br />A new carrier frequency offset estimation scheme in orthogonal frequency-division multiplexing (OFDM) systems is proposed in this paper. Both the carrier frequency offset acquisition and tracking are based on a fixed-length training-symbol-block, which consists of multiple small identical training symbols. When each training symbol is shortened, the number of training symbols in the training-symbol-block should be increased accordingly to keep the total training-symbol-block length fixed. The proposed scheme extends Moose's estimator, where the estimation error is only dependent on total training symbol energy and cannot be reduced any more, once the total training symbol energy is determined. The proposed scheme can shorten each training symbol in a training-symbol block and select an appropriate estimator simultaneously, which can lead to further reduction of estimation error and increase of acquisition range, even with the total training-symbol-block energy being fixed. Performance analyzes for the proposed scheme in both the additive white Gaussian noise channel (AWGN) and the multipath channel are also presented in this paper. All estimators in the proposed scheme are conditionally unbiased, and simulation results demonstrate that they can work well both in the multipath channel and in the AWGN channel. High accuracy frequency offset correction with adjustable acquisition range in OFDM systems Zhongshan Zhang Weiyu Jiang Haiyan Zhou Yuanan Liu Jinchun Gao doi:10.1109/TWC.2004.840201 Wireless Communications, IEEE Transactions on, Vol. 4, No. 1. (2005), pp. 228-237. 2008-02-25T15:40:02-00:00 2005 Wireless Communications, IEEE Transactions on 4 1 228 237 accuracy acquisition frequency ofdm offset