Sun, 27 Jul 2008 07:47:38 BST CiteULike: dcastro's Zhou http://www.citeulike.org/user/dcastro/author/Zhou CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dcastro/article/3040245 <i>Vehicular Technology Conference, 2005. VTC-2005-Fall. 2005 IEEE 62nd, Vol. 4 (2005), pp. 2527-2531.</i> Performance of IEEE 802.11b in mobile railroad environments Ting Zhou H Sharif M Hempel P Mahasukhon Song Ci doi:10.1109/VETECF.2005.1559005 Vehicular Technology Conference, 2005. VTC-2005-Fall. 2005 IEEE 62nd, Vol. 4 (2005), pp. 2527-2531. 2008-07-24T15:38:28-00:00 2005 Vehicular Technology Conference, 2005. VTC-2005-Fall. 2005 IEEE 62nd 4 2527 2531 80211 mobile railway wlan http://www.citeulike.org/user/dcastro/article/2883757 <i>Communications and Information Technology, 2005. ISCIT 2005. IEEE International Symposium on, Vol. 2 (2005), pp. 983-986.</i><br /><br />Ultra-Wide band (UWB) radio, transmits data using nanosecond level impulses, is gaining increasing attention own to its attractive features that include low-complexity hardware and high transmission rate. However, UWB system has to cope with great design challenges, including synchronization, multi-path energy combining. A review of acquisition methods in direct sequence-spread spectrum (DS-SS) communication system is given in detail at first and analysis of their performance with evaluating parameters, which is the essential reference to DS-SS acquisition algorithm is shown next. Then, several acquisition scheme used specially in DS-UWB system is analyzed. Hardware complexity and acquisition performance in DS-UWB is still the two sides of one contradiction needed to be tradeoff. The overview of synchronization in DS-UWB Jun Chen Zheng Zhou doi:10.1109/ISCIT.2005.1567032 Communications and Information Technology, 2005. ISCIT 2005. IEEE International Symposium on, Vol. 2 (2005), pp. 983-986. 2008-06-11T20:26:39-00:00 2005 Communications and Information Technology, 2005. ISCIT 2005. IEEE International Symposium on 2 983 986 synchronization uwb http://www.citeulike.org/user/dcastro/article/2883716 <i>Antennas and Propagation, IEEE Transactions on, Vol. 47, No. 5. (1999), pp. 862-869.</i><br /><br />This paper presents a new pattern synthesis algorithm for arbitrary arrays based on adaptive array theory. With this algorithm, the designer can efficiently control both mainlobe shaping and sidelobe levels. The element weights optimize a weighted L₂ norm between desired and achieved patterns. The values of the weighting function in the L₂ norm, interpreted as imaginary jammers as in Olen and Compton's (1990) method, are iterated to minimize exceedance of the desired sidelobe levels and minimize the absolute difference between desired and achieved mainlobe patterns. The sidelobe control can be achieved by iteration only on sidelobe peaks. In comparison to Olen and Compton's method, the new algorithm provides a great improvement in mainlobe shaping control. Example simulations, including both nonuniform linear and planar arrays, are shown to illustrate the effectiveness of this algorithm Pattern synthesis for arbitrary arrays using an adaptive array method Philip Zhou MA Ingram doi:10.1109/8.774142 Antennas and Propagation, IEEE Transactions on, Vol. 47, No. 5. (1999), pp. 862-869. 2008-06-11T20:14:58-00:00 1999 Antennas and Propagation, IEEE Transactions on 47 5 862 869 adaptive antenna array pattern synthesis http://www.citeulike.org/user/dcastro/article/2877066 <i>Communication Technology, 2006. ICCT '06. International Conference on (2006), pp. 1-5.</i><br /><br />In this paper, we propose and compare two ranging methods for the OFDMA uplink system prescribed by IEEE 802.16e, including multi-user ranging code detection, timing, frequency and power synchronization. In Method I, timing offset estimation is based on the auto-correlation and cross-correlation in time-domain, and an adaptive threshold is defined to detect transmitted ranging codes. The time-domain algorithm has a similar counterpart in the frequency-domain described in Method II, which is more accurate since it bears less interference by extracting the sub-carriers used for ranging from data sub-carriers. Moreover, Method II needs fewer computations since it shares the FFT calculations with the data demodulation process. However, Method I has the advantage of a flexible correlation window size. Simulations confirm that both methods perform well even in the condition of low SNR values and several simultaneous ranging users. To obtain the 90% probability of successful detection, Method II requires an SNR about 3.5dB less than Method I. Simulations also show that both methods are better, compared with some existing methods. OFDMA Initial Ranging for IEEE 802.16e Based on Time-domain and Frequency-domain Approaches Yue Zhou Zhaoyang Zhang Xiangwei Zhou doi:10.1109/ICCT.2006.341784 Communication Technology, 2006. ICCT '06. International Conference on (2006), pp. 1-5. 2008-06-09T14:43:03-00:00 2006 Communication Technology, 2006. ICCT '06. International Conference on 1 5 ofdma synchronization wimax http://www.citeulike.org/user/dcastro/article/2859279 <i>Advanced Information Networking and Applications, 2003. AINA 2003. 17th International Conference on (2003), pp. 318-323.</i><br /><br />The IEEE 802.11 standards support the peer-to-peer mode independent basic service set (IBSS), which is an ad hoc network with all its stations within each other's transmission range. In an IBSS, it is important that all stations are synchronized to a common clock. Synchronization is needed for frequency hopping and power saving. The synchronization mechanism specified in the IEEE 802.11 standards has a severe scalability problem. The probability that stations may get out of synchronization is pretty high in large IBSS. A new synchronization algorithm has been proposed for large-scale ad hoc networks. We propose a more efficient algorithm in this paper that synchronizes the clock more accurately. We are able to synchronize the clock within 100 /spl mu/s when the number of stations is more than 300. This is a big improvement over the current best algorithm and the 802.11 specified protocol. To our best knowledge, the current best algorithm can synchronize the clock within 550 /spl mu/s for a 300-station network. The 802.11 standard protocol can have clock drift over 5000 /spl mu/s for the same network. Efficient,and scalable IEEE 802.11 ad-hoc-mode timing synchronization function Ten-Hwang Lai Dong Zhou doi:10.1109/AINA.2003.1192897 Advanced Information Networking and Applications, 2003. AINA 2003. 17th International Conference on (2003), pp. 318-323. 2008-06-03T14:50:00-00:00 2003 Advanced Information Networking and Applications, 2003. AINA 2003. 17th International Conference on 318 323 ad-hoc synchronization time wifi http://www.citeulike.org/user/dcastro/article/2859153 <i>Circuits and Systems, 2005. ISCAS 2005. IEEE International Symposium on (2005), pp. 2623-2626 Vol. 3.</i><br /><br />Timing synchronization is more critical in orthogonal frequency division multiplexing (OFDM) systems than in single carrier systems. In this paper, a timing estimation scheme is derived from maximum likelihood estimation (MLE) using power delay profile. It is implemented using a delay locked loop (DLL) to achieve fine timing synchronization for OFDM systems. With this scheme, the mean-square error of symbol timing estimation is decreased by orders of magnitude when compared to the simple peak-finding scheme in multipath fading channels. This scheme also shows higher tracking accuracy for symbol timing drift caused by the sampling clock frequency offset. Fine timing synchronization using power delay profile for OFDM systems Hao Zhou Yih-Fang Huang doi:10.1109/ISCAS.2005.1465164 Circuits and Systems, 2005. ISCAS 2005. IEEE International Symposium on (2005), pp. 2623-2626 Vol. 3. 2008-06-03T14:00:31-00:00 2005 Circuits and Systems, 2005. ISCAS 2005. IEEE International Symposium on 2623 2626 Vol. 3 ofdm synchronization time http://www.citeulike.org/user/dcastro/article/2687421 <i>Communications, Circuits and Systems Proceedings, 2006 International Conference on, Vol. 2 (2006), pp. 1147-1152.</i><br /><br />This paper presents a symbol timing synchronization method for interleaved OFDMA uplink system in broadband multipath Rayleigh channel. The proposed timing synchronization method contains two steps: coarse and fine time synchronization. The coarse time synchronization is desired to locate the strongest path while the fine time synchronization is desired to locate the first path and both of the coarse and fine time synchronizations are performed in time domain. Two OFDM symbols are designed for timing synchronization, of which the first is for coarse time synchronization and the second is for fine time synchronization. The user specific pilot signals are constructed in the whole obtained system band in the coarse timing preamble while the user exclusive subcarrier set in the fine timing preamble. In fine time synchronization scheme, for the user specific pilot signals are constructed in different subchannels, they have special ideal autocorrelation and cross-correlation properties, which can well suppress the multi-user interferences. Simulations have been performed in MATRICE channel C, which demonstrate that the proposed timing synchronization method can work well in interleaved OFDMA uplink system. And the proposed timing estimator is also robust in frequency asynchronous environment Timing Synchronization for Interleaved OFDMA Uplink System En Zhou Hui Zhao Wenbo Wang doi:10.1109/ICCCAS.2006.284850 Communications, Circuits and Systems Proceedings, 2006 International Conference on, Vol. 2 (2006), pp. 1147-1152. 2008-04-18T09:15:57-00:00 2006 Communications, Circuits and Systems Proceedings, 2006 International Conference on 2 1147 1152 ofdma synchronization time uplink http://www.citeulike.org/user/dcastro/article/2687422 <i>Communications, 2006. ICC '06. IEEE International Conference on, Vol. 11 (2006), pp. 5086-5090.</i><br /><br />This paper proposes a novel symbol timing synchronization method for localized OFDMA uplink system. Two neighboring pilot symbols are designed for timing synchronization utilizing the property of successive subcarrier assignment. For OFDMA separation, there is almost no inter-user interference, which is very beneficial for timing synchronization. At receiver, the position of the pilot symbols can be found by correlating the received signal with the local pilot replica. For better correlation result, Zadoff-Chu sequence is employed as the pilot data for its ideal autocorrelation property, which can well suppress the inter-multipath interferences. Furthermore, a novel timing metric is constructed according to the obtained correlation profile by using the special pilot structure. The timing metric is proportional to the received SNR and has a plateau since the CP length is designed larger than the maximum channel delay. The timing estimator is dedicated to locate in the middle position of the ISI-free CP part for this timing offset will not degrade system BER performance. Simulations results demonstrate that the proposed timing estimator can work well in localized OFDMA uplink system. As long as the maximum channel delay is shorter than the CP length, it can reach the same BER performance with that of ideal synchronization. A Novel Timing Synchronization Method for Localized OFDMA Uplink System En Zhou Yuyu Yan Wenbo Wang doi:10.1109/ICC.2006.255473 Communications, 2006. ICC '06. IEEE International Conference on, Vol. 11 (2006), pp. 5086-5090. 2008-04-18T09:16:16-00:00 2006 Communications, 2006. ICC '06. IEEE International Conference on 11 5086 5090 ofdma synchronization time uplink 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 http://www.citeulike.org/user/dcastro/article/2425756 <i>Communications and Networking in China, 2006. ChinaCom '06. First International Conference on (2006), pp. 1-5.</i><br /><br />Synchronization process is essential especially in UWB communication system owes to its extremely short transmitted pulse shape and the ultra dense multi-path interference. Acquisition performance decreased rapidly own to serious inter-symbol interference (ISI) caused by those complex channel with relatively large delay spread. An interference resistant adaptive threshold acquisition algorithm (IR-ATAA) for DS-UWB systems proposed here has the feature that the decision threshold changes automatically adapting to the signal to noise ratio (SNR) at time of comparison. The performance analysis mainly focus on the probability of correct acquisition (P_ACQ) and estimation error of timing delay (MSE) with IEEE defined standard channel models and in the presents of multi-access interference (MAI) which is assumed as an additive white Gaussian noise. The simulation results also indicate the superiority of IR-ATAA over the fixed threshold acquisition algorithm Performance Analysis of Adaptive Threshold Acquisition Algorithm in DS-UWB with Multi-path Environment Jun Chen Yong-Bo Zeng Zheng Zhou doi:10.1109/CHINACOM.2006.344808 Communications and Networking in China, 2006. ChinaCom '06. First International Conference on (2006), pp. 1-5. 2008-02-25T15:00:17-00:00 2006 Communications and Networking in China, 2006. ChinaCom '06. First International Conference on 1 5 acquisition algorithm environment multipath threshold uwb http://www.citeulike.org/user/dcastro/article/2003235 <i>Acoustics, Speech, and Signal Processing, 2004. Proceedings. (ICASSP '04). IEEE International Conference on, Vol. 4 (2004), pp. iv-421-iv-424 vol.4.</i><br /><br />Orthogonal frequency division multiplexing (OFDM) transmission with superimposed training is considered in this paper. The superimposed training scheme is promoted for its high bandwidth efficiency, low computational complexity, and possibly improved power amplifier (PA) efficiency. Channel equalization is also straightforward thanks to the OFDM structure. By analyzing the peak-to-average power ratio (PAR) of the superimposed OFDM signal and utilizing a peak power constraint, we demonstrate that it is possible to lose a little in the information signal power, but gain a lot in the power that is devoted to channel sounding. What is the price paid for superimposed training in OFDM? Ning Chen GT Zhou Acoustics, Speech, and Signal Processing, 2004. Proceedings. (ICASSP '04). IEEE International Conference on, Vol. 4 (2004), pp. iv-421-iv-424 vol.4. 2007-11-28T11:36:26-00:00 2004 Acoustics, Speech, and Signal Processing, 2004. Proceedings. (ICASSP '04). IEEE International Conference on 4 iv-421 iv-424 vol.4 acquisition ofdm pn-sequence tracking http://www.citeulike.org/user/dcastro/article/2003178 <i>Vehicular Technology Conference, 2002. VTC Spring 2002. IEEE 55th, Vol. 3 (2002), pp. 1482-1486 vol.3.</i><br /><br />This paper describes an improved synchronization method for MC-CDMA (multi-carrier code division multiple access) systems. The method takes advantage of the properties of OFDM signals and spreading signals without any additional pilots or training sequences. It mainly discusses symbol timing recovery from the time domain and carrier frequency offset from the frequency domain. A low-complex and faster synchronization method for MC-CDMA systems Ying Jiao Chang Hong Xuejun Sun Zucheng Zhou Vehicular Technology Conference, 2002. VTC Spring 2002. IEEE 55th, Vol. 3 (2002), pp. 1482-1486 vol.3. 2007-11-28T11:27:18-00:00 2002 Vehicular Technology Conference, 2002. VTC Spring 2002. IEEE 55th 3 1482 1486 vol.3 cdma multicarrier synchronization http://www.citeulike.org/user/dcastro/article/1915048 <i>Microwave Symposium Digest, 2003 IEEE MTT-S International, Vol. 3 (2003), pp. 1889-1892 vol.3.</i><br /><br />Novel resonators composed of double-spiral inductors and interdigital capacitors are developed, which not only are compact in size but also have no harmonics up to three times of the fundamental frequency. The center frequency is insensitive to the thickness of the substrate. A miniature seven-pole narrow-band HTS bandpass microstrip filter has been designed, fabricated and tested for an astronomy observation application, which requires a center frequency at 610 MHz and 0.82% fractional bandwidth. The computed and measured results are found in excellent agreement. Superconducting microstrip filters using compact resonators with double-spiral inductors and interdigital capacitors Jiafeng Zhou MJ Lancaster F Huang Microwave Symposium Digest, 2003 IEEE MTT-S International, Vol. 3 (2003), pp. 1889-1892 vol.3. 2007-11-14T17:46:09-00:00 2003 Microwave Symposium Digest, 2003 IEEE MTT-S International 3 1889 1892 vol.3 capacitor filters inductor interdigital microstrip http://www.citeulike.org/user/dcastro/article/1902901 <i>Electronics Letters, Vol. 25, No. 16. (1989), pp. 1080-1082.</i><br /><br />A simple multipath delay spread estimation method by cross-channel-interference (CCI) measurement in a mobile radio channel is presented. The theoretical analyses and field test results show that CCI is a good measure of multipath delay spread Simple multipath delay estimation method for digital mobile radio H Zhou S Yoshida T Takeuchi F Ikegami doi:10.1049/el:19890723 Electronics Letters, Vol. 25, No. 16. (1989), pp. 1080-1082. 2007-11-12T14:10:43-00:00 1989 Electronics Letters 25 16 1080 1082 delay digital estimation mobile multipath radio http://www.citeulike.org/user/dcastro/article/1898988 <i>Communications Letters, IEEE, Vol. 8, No. 3. (2004), pp. 171-173.</i><br /><br />A new carrier frequency offset estimation scheme in orthogonal frequency-division multiplexing (OFDM) system is proposed. The carrier frequency offset estimation includes acquisition and tracking, and the acquisition range is as large as one half of overall signal bandwidth. The proposed tracking estimator is a maximum-likelihood estimator, and in AWGN channel, the Cramer-Rao lower bound is met at high signal-to-noise ratio (SNR); in multipath channel, the tracking algorithm works well at moderate SNR. Timing synchronization can be also performed during the course of acquisition. Frequency offset estimation with fast acquisition in OFDM system Zhongshan Zhang Ming Zhao Haiyan Zhou Yuanan Liu Jinchun Gao doi:10.1109/LCOMM.2004.823423 Communications Letters, IEEE, Vol. 8, No. 3. (2004), pp. 171-173. 2007-11-11T15:43:57-00:00 2004 Communications Letters, IEEE 8 3 171 173 acquisition estimation fast frequency ofdm offset system http://www.citeulike.org/user/dcastro/article/1898946 <i>Vehicular Technology Conference, 2001. VTC 2001 Spring. IEEE VTS 53rd, Vol. 1 (2001), pp. 712-716 vol.1.</i><br /><br />An adaptive joint estimation algorithm of carrier frequency, carrier phase and symbol timing offset in OFDM systems is proposed. The synchronization can be divided into three steps. Firstly, the carrier frequency is estimated and corrected based on the cyclic prefix before the OFDM demodulation (FFT). Secondly, carrier phase synchronization and the timing acquisition can be implemented simultaneously based on the pilot symbols after OFDM demodulation. Thirdly, the above coarse timing algorithm acquires synchronization alignment to within several samples, then the fine timing algorithm estimates and corrects this residual timing offset. Simulations show the carrier frequency and phase estimator has a good performance, the timing algorithm can acquire the synchronization position and eliminate the effect of residual timing offset completely. The advantage of this algorithm is simple computation and only a little resource loss due to pilot symbols A joint estimation algorithm of symbol timing and carrier offset in OFDM systems Jun Wu Qun Zhou KKM Cheng Vehicular Technology Conference, 2001. VTC 2001 Spring. IEEE VTS 53rd, Vol. 1 (2001), pp. 712-716 vol.1. 2007-11-11T15:32:16-00:00 2001 Vehicular Technology Conference, 2001. VTC 2001 Spring. IEEE VTS 53rd 1 712 716 vol.1 algorithm carrier estimation frequency ofdm offset system time