Sat, 26 Jul 2008 06:13:34 BST CiteULike: dcastro's Yang http://www.citeulike.org/user/dcastro/author/Yang CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dcastro/article/1443169 <i>Pervasive Computing and Communications, 2005. PerCom 2005. Third IEEE International Conference on (2005), pp. 85-94.</i><br /><br />In this paper, we present a novel method to adapt the temporal radio maps for indoor location estimation by off-setting the variational environmental factors using data mining techniques and reference points. Environmental variations, which cause the signals to change from time to time even at the same location, present a challenging task for indoor location estimation in the IEEE 802.11b infrastructure. In such a dynamic environment, the radio maps obtained in one time period may not be applicable in other time periods. To solve this problem, we apply a regression analysis to learn the temporal predictive relationship between the signal-strength values received by sparsely located reference points and that received by the mobile device. This temporal prediction model can then be used for online localization based on the newly observed signal-strength values at the client side and the reference points. We show that this technique can effectively accommodate the variations of signal-strength values over different time periods without the need to rebuild the radio maps repeatedly. We also show that the location of mobile device can be accurately determined using this technique with lower density in the distribution of the reference points. Adaptive Temporal Radio Maps for Indoor Location Estimation Jie Yin Qiang Yang Lionel Ni doi:10.1109/PERCOM.2005.7 Pervasive Computing and Communications, 2005. PerCom 2005. Third IEEE International Conference on (2005), pp. 85-94. 2007-07-08T21:07:55-00:00 2005 Pervasive Computing and Communications, 2005. PerCom 2005. Third IEEE International Conference on 85 94 indoor location http://www.citeulike.org/user/dcastro/article/3021116 <i>Antennas and Propagation Society International Symposium, 1993. AP-S. Digest (1993), pp. 1478-1481 vol.3.</i><br /><br />The authors describe the preliminary designs of two different types of microstrip antennas, i.e., those providing dual-frequency circularly-polarized (CP) operation; and enhanced low-angle radiation. The first type of antennas was designed to operate at the GPS (Global Positioning System) frequencies of 1.227 and 1.575 GHz, and was fabricated by using a novel combination of recessed cavity and patch type of resonators. For the second type of antenna, achieving enhanced gain at lower angles without sacrificing the CP performance turned out to be a difficult challenge. After many unsuccessful attempts, a preliminary design that employed a pyramidal configuration appeared to exhibit good promise and favorable potential for further improvement Microstrip patch antennas for GPS applications R Mittra R Yang M Itoh M Arakawa doi:10.1109/APS.1993.385474 Antennas and Propagation Society International Symposium, 1993. AP-S. Digest (1993), pp. 1478-1481 vol.3. 2008-07-19T17:10:57-00:00 1993 Antennas and Propagation Society International Symposium, 1993. AP-S. Digest 1478 1481 vol.3 antenna application gps microstrip patch http://www.citeulike.org/user/dcastro/article/3015428 <i>Antennas and Propagation, 2007. EuCAP 2007. The Second European Conference on (2007), pp. 1-6.</i><br /><br />A GaAs MMIC technology of the novel compact left-handed bandpass filter consisting of one left-handed (LH) transmission line (TL) and one dual composite right/lefthanded (D-CRLH) TL is presented. The D-CRLH is the dual of the conventional CRLH in the sense that it consists of a LC parallel-tank impedance and of a LC series-tank admittance. In contrast to the conventional CRLH TL which has LH operation at low-frequency and RH one at high-frequency, the D-LH TL exhibits its LH band at high frequencies and its RH band at low frequencies. Thus, utilizing the high pass property of LH and low pass property of D-CRLH, a bandpass filter can be constructed. In this paper, this novel idea is realized by MMIC technology. The proposed filter exhibits a broad passband from 6.2 GHz to 20.8 GHz with a size of 1.43 mm². Compact Fully Integrated GaAs Left-Handed Bandpass Filter for Ultrawide Band Wireless Applications W Tong H Yang Z Hu H Zhang Antennas and Propagation, 2007. EuCAP 2007. The Second European Conference on (2007), pp. 1-6. 2008-07-17T19:56:34-00:00 2007 Antennas and Propagation, 2007. EuCAP 2007. The Second European Conference on 1 6 crlh filter lh metamaterial uwb wireless http://www.citeulike.org/user/dcastro/article/333435 <i>Signal Processing Magazine, IEEE, Vol. 21, No. 6. (2004), pp. 26-54.</i><br /><br />Ultra-wideband (UWB) radio is a fast emerging technology with many unique attractive features that promotes major advances in wireless communications, networking, radar, imaging, and positioning systems. Research in UWB is still in its infancy stages, offering limited resources in handling the challenges facing the UWB communications. Understanding the unique properties and challenges of UWB communications as well as its application in competent signal processing techniques are vital in conquering the obstacles towards developing exciting UWB applications. UWB research and development has to cope with the challenges that limit their performance, capacity, throughput, network flexibility, implementation complexity, and cost. This tutorial focuses on UWB wireless communications at the physical layer. It overviews the state-of-the-art UWB in channel modeling, transmitters, and receivers of UWB radios, and outlines the research directions and challenges that needs to be overcome. Since a signal processing expertise is expected to have major impact in research and development of UWB systems, emphasis is placed on the DSP aspects. Ultra-wideband communications: an idea whose time has come Liuqing Yang GB Giannakis doi:10.1109/MSP.2004.1359140 Signal Processing Magazine, IEEE, Vol. 21, No. 6. (2004), pp. 26-54. 2005-09-28T01:27:21-00:00 2004 Signal Processing Magazine, IEEE 21 6 26 54 uwb http://www.citeulike.org/user/dcastro/article/2822642 <i>Custom Integrated Circuits Conference, 2007. CICC '07. IEEE (2007), pp. 627-630.</i><br /><br />This paper presents a comprehensive model for analyzing the behavior of an analog delay-locked loop (DLL). Unlike previous models, the proposed version includes both constant and variable phase-offset terms, making it possible to calculate jitter transfer characteristics, stability, and static phase errors from a single unified model. The topology more closely approximates the underlying architecture of the DLL, resulting in improved accuracy and enabling better tradeoffs between bandwidth, stability, and power. A Comprehensive Phase-Transfer Model for Delay-Locked Loops JR Burnham Gu-Yeon Wei Chih-Kong Yang H Hindi doi:10.1109/CICC.2007.4405810 Custom Integrated Circuits Conference, 2007. CICC '07. IEEE (2007), pp. 627-630. 2008-05-22T09:25:57-00:00 2007 Custom Integrated Circuits Conference, 2007. CICC '07. IEEE 627 630 dll http://www.citeulike.org/user/dcastro/article/2809068 <i>Signal Processing and Communications, 2004. SPCOM '04. 2004 International Conference on (2004), pp. 540-544.</i> Subcarrier allocation schemes for multiuser OFDM systems A Pandharipande M Kountouris Ho Yang Hyoungwoon Park Signal Processing and Communications, 2004. SPCOM '04. 2004 International Conference on (2004), pp. 540-544. 2008-05-18T14:06:03-00:00 2004 Signal Processing and Communications, 2004. SPCOM '04. 2004 International Conference on 540 544 allocation frequency multiuser ofdm http://www.citeulike.org/user/dcastro/article/2808917 <i>PROCEEDINGS OF ISAP2005 (2005)</i> A Novel Design of Balun using Left-Handed Transmission Line Seungjun Lee Jong-Sik Lim Hoe-Sung Yang Sangwook Nam PROCEEDINGS OF ISAP2005 (2005) 2008-05-18T12:24:35-00:00 2005 PROCEEDINGS OF ISAP2005 balun crlh metamaterial tl http://www.citeulike.org/user/dcastro/article/2802228 <i>Vehicular Technology Conference, 1999 IEEE 49th, Vol. 3 (1999), pp. 2398-2402 vol.3.</i><br /><br />This paper compares the mean acquisition time performance of two serial search acquisition schemes over frequency-selective multipath Rayleigh fading channels. Both the conventional cell-by-cell detection and the novel joint twin-cell detection are characterised. In contrast to the majority of published results considering only one correct timing state (Hi cell) in the uncertainty region of the pseudo noise (PN) sequence, this paper aims to analyse the mean acquisition time performance of a serial search so acquisition scheme considering multiple timing states in the uncertainty region. The mean acquisition time performance comparison between the conventional cell-by-cell detection and the joint twin-cell detection shows that the latter can achieve significantly improved acquisition time performance at almost the same complexity Serial acquisition techniques for DS-CDMA signals in frequency-selective multi-user mobile channels Lie-Liang Yang L Hanzo doi:10.1109/VETEC.1999.778503 Vehicular Technology Conference, 1999 IEEE 49th, Vol. 3 (1999), pp. 2398-2402 vol.3. 2008-05-15T17:46:50-00:00 1999 Vehicular Technology Conference, 1999 IEEE 49th 3 2398 2402 vol.3 acquisition cdma channel frequency mobile sequential spread-spectrum http://www.citeulike.org/user/dcastro/article/2802206 <i>Selected Areas in Communications, IEEE Journal on, Vol. 14, No. 3. (1996), pp. 477-491.</i><br /><br />This paper uses the results of ray tracing in a typical indoor test area to compare the performance of major radio transmission techniques that are used as the air interface in evolving standards and major wireless local area network (WLAN) products. The performance of direct sequence (DS) and frequency hopping spread spectrum (FHSS) in the test area are compared with the performance of multicarrier modems, as well as modems using decision feedback equalization (DFE) and sectored antenna systems (SAS). The validity of using ray tracing for performance evaluation is examined by comparing the results with the results of performance evaluation obtained from the empirical measurement of the channel characteristics. Based on the maximum achievable data rate and minimum power requirement determined in the test area, operation of all modems in bandlimited and power limited applications are discussed Transmission techniques for radio LAN's-a comparative performance evaluation using ray tracing A Falsafi K Pahlavan Ganning Yang doi:10.1109/49.490233 Selected Areas in Communications, IEEE Journal on, Vol. 14, No. 3. (1996), pp. 477-491. 2008-05-15T17:42:08-00:00 1996 Selected Areas in Communications, IEEE Journal on 14 3 477 491 technique transmission wlan http://www.citeulike.org/user/dcastro/article/2802192 <i>Vehicular Technology, IEEE Transactions on, Vol. 50, No. 2. (2001), pp. 617-628.</i><br /><br />This paper compares the mean acquisition time (MAT) performance of two serial search acquisition schemes over frequency-selective multipath Rayleigh fading channels. Both the conventional cell-by-cell detection and the novel joint two-cell detection are characterized. In contrast to the majority of published results considering only one correct timing state (H₁ cell) in the uncertainty region of the pseudonoise (PN) sequence, this paper analyzes the MAT performance of the serial search acquisition schemes with multiple timing states in the uncertainty region. The MAT performance comparison between the conventional cell-by-cell detection and the joint two-cell detection shows that the latter can achieve an improved acquisition performance at almost the same complexity Serial acquisition of DS-CDMA signals in multipath fading mobile channels Lie-Liang Yang L Hanzo doi:10.1109/25.923073 Vehicular Technology, IEEE Transactions on, Vol. 50, No. 2. (2001), pp. 617-628. 2008-05-15T17:38:43-00:00 2001 Vehicular Technology, IEEE Transactions on 50 2 617 628 cdma channel fading mobile multipath http://www.citeulike.org/user/dcastro/article/2782070 <i>Microwave Symposium Digest, 1999 IEEE MTT-S International, Vol. 3 (1999), pp. 919-922 vol.3.</i><br /><br />A novel lowpass filter with a uniplanar, compact photonic band-gap structure etched in the ground plane has been proposed and demonstrated. This new filter has a deep attenuation and spurious-free response. A drain mixer using this novel filter suppresses the LO leakage by over 10 dB compared to a reference mixer with a conventional filter A novel uniplanar compact PBG structure for filter and mixer applications Fei-Ran Yang Yongxi Qian T Itoh doi:10.1109/MWSYM.1999.779536 Microwave Symposium Digest, 1999 IEEE MTT-S International, Vol. 3 (1999), pp. 919-922 vol.3. 2008-05-10T00:03:34-00:00 1999 Microwave Symposium Digest, 1999 IEEE MTT-S International 3 919 922 vol.3 compact mixer pbg structure http://www.citeulike.org/user/dcastro/article/2782005 <i>Circuits and Systems II: Analog and Digital Signal Processing, IEEE Transactions on [see also Circuits and Systems II: Express Briefs, IEEE Transactions on], Vol. 50, No. 11. (2003), pp. 870-878.</i><br /><br />This paper describes a run-time adaptive method of minimizing jitter for a phase-locked loop (PLL). The design employs digital tuning that independently adjusts each loop parameter of the PLL. The loop is fabricated in 0.25 /spl mu/m CMOS and uses a 2.5 V supply. The proposed method measures the output jitter on-chip and adjusts the PLL loop parameters toward minimizing the jitter by a closed-loop control system. The experimental results verify the success of the proposed method in minimizing jitter to within 5 ps of the minimum peak-to-peak jitter. Methodology for on-chip adaptive jitter minimization in phase-locked loops M Mansuri A Hadiashar Chih-Kong Yang doi:10.1109/TCSII.2003.819124 Circuits and Systems II: Analog and Digital Signal Processing, IEEE Transactions on [see also Circuits and Systems II: Express Briefs, IEEE Transactions on], Vol. 50, No. 11. (2003), pp. 870-878. 2008-05-09T23:43:06-00:00 2003 Circuits and Systems II: Analog and Digital Signal Processing, IEEE Transactions on [see also Circuits and Systems II: Express Briefs, IEEE Transactions on] 50 11 870 878 jitter pll time http://www.citeulike.org/user/dcastro/article/2776227 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 47, No. 11. (1999), pp. 2092-2098.</i><br /><br />A novel waveguide using a photonic bandgap (PBG) structure is presented. The PBG structure is a two-dimensional square lattice with each cell consisting of metal pads and four connecting lines, which are etched on a conductor-backed Duroid substrate. This uniplanar compact PBG structure realizes a magnetic surface in the stopband and is used in the waveguide walls to provide magnetic boundary conditions. A relatively uniform field distribution along the cross section has been measured at frequencies from 9.4 to 10.4 GHz. Phase velocities close to the speed of light have also been observed in the stopband, indicating that TEM mode has been established. A recently developed quasi-Yagi antenna has been employed as a broad-band and efficient waveguide transition. Meanwhile, full-wave simulations using the finite-difference time-domain method provide accurate predictions for the characteristics of both the perfect magnetic conductor impedance surface and the waveguide structure. This novel waveguide structure should find a wide range of applications in different areas, including quasi-optical power combining and the electromagnetic compatibility testing A novel TEM waveguide using uniplanar compact photonic-bandgap (UC-PBG) structure Fei-Ran Yang Kuang-Ping Ma Yongxi Qian T Itoh doi:10.1109/22.798004 Microwave Theory and Techniques, IEEE Transactions on, Vol. 47, No. 11. (1999), pp. 2092-2098. 2008-05-09T16:10:18-00:00 1999 Microwave Theory and Techniques, IEEE Transactions on 47 11 2092 2098 pbg http://www.citeulike.org/user/dcastro/article/2776179 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 47, No. 11. (1999), pp. 2123-2130.</i><br /><br />The recently developed uniplanar compact photonic bandgap (UC-PBG) substrate is successfully used to reduce surface-wave losses for an aperture-coupled fed patch antenna on a thick high dielectric-constant substrate. The surface-wave dispersion diagram of the UC-PBG substrate has been numerically computed for two different substrate thickness (25 and 50 mil) and found to have a complete stopband in the frequency range of 10.9-13.5 and 11.4-12.8 GHz, respectively. The thicker substrate is then used to enhance broadside gain of a patch antenna working in the stopband at 12 GHz. Computed results and measured data show that, due to effective surface-wave suppression, the antenna mounted on the UC-PBG substrate has over 3-dB higher gain in the broadside direction than the same antenna etched on a grounded dielectric slab with same thickness and dielectric constant. Cross-polarization level remains 13 dB down the co-polar component level for both E- and H-planes Aperture-coupled patch antenna on UC-PBG substrate R Coccioli Fei-Ran Yang Kuang-Ping Ma T Itoh doi:10.1109/22.798008 Microwave Theory and Techniques, IEEE Transactions on, Vol. 47, No. 11. (1999), pp. 2123-2130. 2008-05-09T15:42:39-00:00 1999 Microwave Theory and Techniques, IEEE Transactions on 47 11 2123 2130 antenna patch pbg http://www.citeulike.org/user/dcastro/article/2774599 <i>Microwave Symposium Digest, 1998 IEEE MTT-S International, Vol. 2 (1998), pp. 997-1000 vol.2.</i><br /><br />This paper presents a novel idea that the power is fed from the patch antenna coupler to form a five-element Chebyshev active antenna FET amplifying linear array. An equivalent lumped element circuit was developed to model the mutual coupling having good agreement with experiments. The power level coupled to the transmission line can be controlled by adjusting the length and the gap of the transmission line. The active patch-fed antenna coupler array has the advantages of a single input port, no power divider required, good and controllable radiation patterns, ease of bias, and compactness Novel active antenna amplifying arrays Yao-Chou Yang Shyh-Jong Chung Kai Chang doi:10.1109/MWSYM.1998.705160 Microwave Symposium Digest, 1998 IEEE MTT-S International, Vol. 2 (1998), pp. 997-1000 vol.2. 2008-05-09T07:24:23-00:00 1998 Microwave Symposium Digest, 1998 IEEE MTT-S International 2 997 1000 vol.2 active amplifier antenna array http://www.citeulike.org/user/dcastro/article/2774524 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 49, No. 8. (2001), pp. 1492-1497.</i><br /><br />In this paper, an active four-element patch antenna, backed by four GaAs monolithic-microwave integrated-circuit (MMIC) 4.4-GHz oscillators, self-locked by mutual coupling through a lumped capacitive ring MMIC network, has been designed, fabricated, and tested. The sequentially rotated arrangement given here when augmented with a lumped capacitive coupling network suggests that in-phase oscillator entrainment is guaranteed so that spatial power combination by the antenna array occurs with circular polarization characteristics Ring-coupled-oscillator sequentially rotated active antenna Suidong Yang VF Fusco DEJ Humphrey doi:10.1109/22.939931 Microwave Theory and Techniques, IEEE Transactions on, Vol. 49, No. 8. (2001), pp. 1492-1497. 2008-05-09T06:44:39-00:00 2001 Microwave Theory and Techniques, IEEE Transactions on 49 8 1492 1497 active antenna oscillator rotation sequential http://www.citeulike.org/user/dcastro/article/2774521 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 47, No. 5. (1999), pp. 629-635.</i><br /><br />This paper presents the theory of a microstrip line on artificial periodic substrates. A two-stage moment method in conjunction with an array-scanning scheme is proposed for the microstrip characterization. The analytic and numerical methods dealing with the interaction of microstrip components (continuous plane-wave spectrum) with artificial periodic materials (discrete plane-wave spectrum, Floquet modes) are discussed. The method of solution involves two stages of vector integral equations and moment methods. The first integral-equation formulation is to find the Green's function for a planar periodic structure. A spectral-domain moment method is applied to the second vector integral equation to determine the fields or currents on the circuit components and the associated parameters of interest. Guided-wave characteristics of a microstrip line on artificial periodic substrates, including the propagation constant and the characteristic impedance, are investigated. Propagation bandgap of a microstrip line due to periodic elements is characterized. Experiment on a three-layer microstrip-line structure with a periodic mid-layer is conducted to validate the theory Theory of microstrip lines on artificial periodic substrates Hung-Yu Yang doi:10.1109/22.763165 Microwave Theory and Techniques, IEEE Transactions on, Vol. 47, No. 5. (1999), pp. 629-635. 2008-05-09T06:44:35-00:00 1999 Microwave Theory and Techniques, IEEE Transactions on 47 5 629 635 line microstrip tl http://www.citeulike.org/user/dcastro/article/2764002 <i>Wireless Communications, Networking and Mobile Computing, 2007. WiCom 2007. International Conference on (2007), pp. 645-648.</i> The Research of Side-Band Acquisition for BOC-Modulated Signal Li Yang Chengsheng Pan Yongxin Feng Yuming Bo doi:10.1109/WICOM.2007.167 Wireless Communications, Networking and Mobile Computing, 2007. WiCom 2007. International Conference on (2007), pp. 645-648. 2008-05-07T06:41:16-00:00 2007 Wireless Communications, Networking and Mobile Computing, 2007. WiCom 2007. International Conference on 645 648 acquisition boc gnss signal http://www.citeulike.org/user/dcastro/article/2762225 <i>Antennas and Propagation Society International Symposium, 2000. IEEE, Vol. 3 (2000), pp. 1796-1799 vol.3.</i><br /><br />A low-profile cavity-backed slot antenna is proposed using a uniplanar compact photonic band-gap (UC-PBG) structure, which is a 2D periodic metallic pattern loaded on a thin dielectric slab backed with a ground plane. The UC-PBG substrate behaves like an open boundary at the resonant frequency and this property is exploited to reduce the cavity size while keeping good antenna performance Low-profile cavity-backed slot antenna using UC-PBG substrate F Yang Y Qian T Itoh doi:10.1109/APS.2000.874593 Antennas and Propagation Society International Symposium, 2000. IEEE, Vol. 3 (2000), pp. 1796-1799 vol.3. 2008-05-06T18:30:55-00:00 2000 Antennas and Propagation Society International Symposium, 2000. IEEE 3 1796 1799 vol.3 antenna pbg http://www.citeulike.org/user/dcastro/article/2762223 <i>Antennas and Propagation Society International Symposium, 1999. IEEE, Vol. 3 (1999), pp. 1920-1923 vol.3.</i><br /><br />The previously developed uniplanar compact PBG (UC-PBG) substrate is successfully used to reduce surface wave losses of a patch antenna on a high-dielectric constant substrate. The surface wave dispersion diagram of the UC-PBG substrate has been numerically computed and found to have a complete bandgap in the range of frequency 10.9-13.5 GHz. This feature is exploited to enhance both bandwidth and broadside gain of a patch antenna working at the frequency 11.5 GHz in the forbidden bandgap. Measured results show a 2.8 dB higher radiation in the broadside direction than that of a standard patch antenna built on the same high-permittivity grounded dielectric slab PBG-assisted gain enhancement of patch antennas on high-dielectric constant substrate FR Yang R Coccioli Y Qian T Itoh doi:10.1109/APS.1999.788333 Antennas and Propagation Society International Symposium, 1999. IEEE, Vol. 3 (1999), pp. 1920-1923 vol.3. 2008-05-06T18:30:52-00:00 1999 Antennas and Propagation Society International Symposium, 1999. IEEE 3 1920 1923 vol.3 antenna patch pbg http://www.citeulike.org/user/dcastro/article/2762218 <i>Electronics Letters, Vol. 34, No. 21. (1998), pp. 2041-2042.</i><br /><br />The realisation of a magnetic conducting surface using a novel two-dimensional uniplanar photonic bandgap structure is described. This novel idea is verified by measured results and the results obtained using the finite-difference time-domain method Realisation of magnetic conducting surface using novel photonic bandgap structure KP Ma K Hirose FR Yang Y Qian T Itoh Electronics Letters, Vol. 34, No. 21. (1998), pp. 2041-2042. 2008-05-06T18:28:49-00:00 1998 Electronics Letters 34 21 2041 2042 pbg http://www.citeulike.org/user/dcastro/article/2758009 <i>Electronics Letters, Vol. 35, No. 17. (1999), pp. 1401-1403.</i><br /><br />The cancellation of inter-modulation distortion (IMD) using linearisation techniques has traditionally been performed at the amplifier. The authors present a circular patch antenna operating at 1.93 GHz, which also functions as a four way combiner and an IMD cancellation circuit Low IMD, antenna combined, circularly polarised, integrated antenna Chi Yang Wing-Le Chan Wing Chan doi:10.1049/el:19990959 Electronics Letters, Vol. 35, No. 17. (1999), pp. 1401-1403. 2008-05-05T14:11:53-00:00 1999 Electronics Letters 35 17 1401 1403 active antenna circularly integrated polarisation http://www.citeulike.org/user/dcastro/article/2674773 <i>Broadcasting, IEEE Transactions on, Vol. 52, No. 2. (2006), pp. 236-244.</i><br /><br />The latest research works on the synchronization scheme for either continuous transmission mode or burst packet transmission mode for the wireless OFDM communications are overviewed in this paper. The typical algorithms dealing with the symbol timing synchronization, the carrier frequency synchronization as well as the sampling clock synchronization are briefly introduced and analyzed. Three improved methods for the fine symbol timing synchronization in frequency domain are also proposed, with several key issues on the synchronization for the OFDM systems discussed. On the synchronization techniques for wireless OFDM systems Bo Ai Zhi-Xing Yang Chang-Yong Pan Jian-Hua Ge Yong Wang Zhen Lu doi:10.1109/TBC.2006.872990 Broadcasting, IEEE Transactions on, Vol. 52, No. 2. (2006), pp. 236-244. 2008-04-15T18:15:56-00:00 2006 Broadcasting, IEEE Transactions on 52 2 236 244 ofdm synchronization technique wireless http://www.citeulike.org/user/dcastro/article/2011407 <i>Communications Magazine, IEEE, Vol. 43, No. 1. (2005), pp. 53-60.</i><br /><br />Orthogonal frequency-division multiplexing is a popular method for high-data-rate wireless transmission. OFDM may be combined with multiple antennas at both the access point and mobile terminal to increase diversity gain and/or enhance system capacity on a time-varying multipath fading channel, resulting in a multiple-input multiple-output OFDM system. In this article we give a brief technical overview of MIMO-OFDM system design. We focus on various research topics for the MIMO-OFDM-based air interface, including spatial channel modeling, MIMO-OFDM transceiver design, MIMO-OFDM channel estimation, space-time techniques for MIMO-OFDM, and error correction code. The corresponding link-level simulation results are encouraging, and show that MIMO-OFDM is a promising road to future broadband wireless access. A road to future broadband wireless access: MIMO-OFDM-Based air interface Hongwei Yang doi:10.1109/MCOM.2005.1381875(410) 4 Communications Magazine, IEEE, Vol. 43, No. 1. (2005), pp. 53-60. 2007-11-29T07:26:01-00:00 2005 Communications Magazine, IEEE 43 1 53 60 broadband mimo ofdm wireless http://www.citeulike.org/user/dcastro/article/2187888 <i>Antennas and Propagation Society International Symposium, 2002. IEEE, Vol. 4 (2002), pp. 720-723 vol.4.</i><br /><br />Most current GPS receivers only use the L1 frequency of 1.575 GHz with right hand circular polarization. However, in some applications that need more accurate information, differential GPS is employed and an antenna is required to cover both L1 and L2 (1.227 GHz) bands with CP patterns. Recently, we proposed a square patch antenna with switchable slots for dual band CP operation (see Yang, F. and Rahmat-Samii, Y., Electronics Lett., vol.37, p.1002-3, 2001). It has attractive features of a single layer, a single feed, and small frequency ratio. Hence, such an antenna is proposed for GPS applications. The antenna structure and its design procedure are detailed. A single layer dual band circularly polarized microstrip antenna for GPS applications Fan Yang Y Rahmat-Samii doi:10.1109/APS.2002.1017084 Antennas and Propagation Society International Symposium, 2002. IEEE, Vol. 4 (2002), pp. 720-723 vol.4. 2008-01-02T12:03:17-00:00 2002 Antennas and Propagation Society International Symposium, 2002. IEEE 4 720 723 vol.4 antenna circularly dual-band gps microstrip polarisation http://www.citeulike.org/user/dcastro/article/2002932 <i>Broadcasting, IEEE Transactions on, Vol. 49, No. 3. (2003), pp. 304-308.</i><br /><br />A novel timing recovery method which combines code acquisition and symbol timing recovery for TDS-OFDM (time domain synchronous OFDM) is developed. The method is based on the searching and tracking of the correlation peaks of the PN sequences embedded in the signals. Simulations show that this algorithm has very good performance for both AWGN and multipath channels, even when a small frequency offset exists in the sampling clock of the receiver. A combined code acquisition and symbol timing recovery method for TDS-OFDM Jun Wang Zhi-Xing Yang Chang-Yong Pan Meng Han Lin Yang Broadcasting, IEEE Transactions on, Vol. 49, No. 3. (2003), pp. 304-308. 2007-11-28T10:51:04-00:00 2003 Broadcasting, IEEE Transactions on 49 3 304 308 acquisition code ofdm synchronization time http://www.citeulike.org/user/dcastro/article/2002922 <i>Selected Areas in Communications, IEEE Journal on, Vol. 18, No. 11. (2000), pp. 2278-2291.</i><br /><br />Orthogonal frequency division multiplexing (OFDM) is an effective modulation technique for high-rate and high-speed transmission over frequency selective fading channels. However, OFDM systems can be extremely sensitive and vulnerable to synchronization errors. In this paper, we present a scheme for performing timing recovery that includes symbol synchronization and sampling clock synchronization in OFDM systems. The scheme is based on pilot subcarriers. In the scheme, we use a path time delay estimation method to improve the accuracy of the correlation-based symbol synchronization methods, and use a delay-locked loop (DLL) to do the sampling clock synchronization. It is shown that by using this scheme, the mean square values of the symbol timing estimation error can be decreased by several orders of magnitude compared to the common correlation methods in both the AWGN and multipath fading channels. In addition, the scheme can track the symbol timing drift caused by the sampling clock frequency offsets Timing recovery for OFDM transmission Baoguo Yang KB Letaief RS Cheng Zhigang Cao doi:10.1109/49.895033 Selected Areas in Communications, IEEE Journal on, Vol. 18, No. 11. (2000), pp. 2278-2291. 2007-11-28T10:49:39-00:00 2000 Selected Areas in Communications, IEEE Journal on 18 11 2278 2291 ofdm synchronization time http://www.citeulike.org/user/dcastro/article/2002785 <i>Communications, IEEE Transactions on, Vol. 49, No. 3. (2001), pp. 467-479.</i><br /><br />We present an improved channel estimation algorithm for orthogonal frequency-division multiplexing mobile communication systems using pilot subcarriers. This algorithm is based on a parametric channel model where the channel frequency response is estimated using an L-path channel model. In the algorithm, we employ the ESPRIT (estimation of signal parameters by rotational invariance techniques) method to do the initial multipath time delays acquisition and propose an interpath interference cancellation delay locked loop to track the channel multipath time delays. With the multipath time delays information, a minimum mean square error estimator is derived to estimate the channel frequency response. It is demonstrated that the use of the parametric channel model can effectively reduce the signal subspace dimension of the channel correlation matrix for the sparse multipath fading channels and, consequently, improve the channel estimation performance Channel estimation for OFDM transmission in multipath fading channels based on parametric channel modeling Baoguo Yang KB Letaief RS Cheng Zhigang Cao doi:10.1109/26.911454 Communications, IEEE Transactions on, Vol. 49, No. 3. (2001), pp. 467-479. 2007-11-28T10:30:31-00:00 2001 Communications, IEEE Transactions on 49 3 467 479 channel estimation model multipath ofdm transmission http://www.citeulike.org/user/dcastro/article/1870048 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 54, No. 7. (2006), pp. 2902-2909.</i><br /><br />Microwave components with nonlinear phase responses are developed using a simplified composite right/left-handed (CRLH) transmission-line (TL) structure without the series capacitance or the shunt inductance. Using such a simplified CRLH structure, arbitrarily dual-band microstrip components have been realized in compact sizes such as a quarter-wavelength short-circuited stub and dual- band branch-line couplers. Simulation and measurement results are given to demonstrate the efficiency and good performance of the proposed components. For the quarter- wavelength short-circuited stub based on the simplified CRLH-TL structure without the series capacitance, it has been shown that the insertion loss is less than -0.1dB. For the arbitrarily dual-band branch-line coupler, experiment results exhibit that S/sub 21/ and S/sub 31/ are larger than -3.6dB, the isolations are smaller than -30dB, the return losses are smaller than -20dB, and the phase differences are within 90/spl deg//spl plusmn/1.8/spl deg/. Arbitrarily dual-band components using simplified structures of conventional CRLH TLs Xian Lin Ruo Liu Xin Yang Ji Chen Xiao Yin Qiang Cheng Tie Cui Microwave Theory and Techniques, IEEE Transactions on, Vol. 54, No. 7. (2006), pp. 2902-2909. 2007-11-05T20:33:09-00:00 2006 Microwave Theory and Techniques, IEEE Transactions on 54 7 2902 2909 component crlh dual-band structure http://www.citeulike.org/user/dcastro/article/1856858 <i>Microwave Conference Proceedings, 2005. APMC 2005. Asia-Pacific Conference Proceedings, Vol. 1 (2005), 4 pp..</i><br /><br />In this paper, new structures with nonlinear phase responses are proposed based on the composite right /left-handed (CRLH) transmission lines. Using such improved CRLH structure, arbitrary dual-band microstrip components have been realized, such as a quarter-wavelength open/short-circuited stub, and a dual-band branch-line coupler, etc. This has been demonstrated by both simulated and measured results. Compared to the conventional CRLH structures, the novel components are more compact and are easier to be realized. Realization of arbitrary dual-band components using an improved CRLH transmission-line model Xian Lin Ruo Liu Xin Yang Ji Chen Xiao Yin Qiang Cheng Tie Cui Microwave Conference Proceedings, 2005. APMC 2005. Asia-Pacific Conference Proceedings, Vol. 1 (2005), 4 pp.. 2007-11-02T17:41:40-00:00 2005 Microwave Conference Proceedings, 2005. APMC 2005. Asia-Pacific Conference Proceedings 1 4 pp. component crlh dual-band model