The Experts below are selected from a list of 171 Experts worldwide ranked by ideXlab platform
Lajos Hanzo - One of the best experts on this subject based on the ideXlab platform.
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Initial acquisition performance of the Multiple Receive Antenna assisted DS-UWB downlink using Search Space Reduction and iterative code phase estimation
IEEE Transactions on Wireless Communications, 2009Co-Authors: Lajos HanzoAbstract:In this paper we propose and investigate an iterative code acquisition scheme assisted by both search space reduction (SSR) and iterative message passing (MP), which was designed for the Multiple Receive Antenna assisted direct sequence-ultra wideband (DS-UWB) downlink (DL). The performance of this iterative code acquisition scheme is analysed in terms of both the correct detection probability and the achievable mean acquisition time (MAT). We propose an improved criterion for designing the iterative MP based two-stage acquisition regime in terms of the achievable MAT performance. Our proposed scheme is capable of reducing the MAT by several orders of magnitude compared to the benchmark scenario, when considering the employment of long pseudonoise (PN) codes suitable for a variety of applications.
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VTC Fall - Iterative Spreading-Sequence Acquisition in the Multiple Receive Antenna Aided DS-UWB Downlink
2008 IEEE 68th Vehicular Technology Conference, 2008Co-Authors: Lajos HanzoAbstract:In this paper we investigate an iterative message passing (MP) aided Pseudonoise (PN) sequence acquisition scheme employing both beneficially selected generator polynomials (GPs) and Multiple Receive Antennas in the direct sequence-ultra wideband (DS-UWB) downlink (DL). The performance of this iterative acquisition scheme is analysed in terms of the achievable correct detection probability. Our scheme leads to an improved correct detection performance over an extended coverage area.
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adaptive bayesian space time equalisation for Multiple Receive Antenna assisted single input Multiple output systems
Digital Signal Processing, 2008Co-Authors: Sheng Chen, Lajos HanzoAbstract:This contribution considers nonlinear space-time equalisation (STE) for Multiple Receive-Antenna induced single-input Multiple-output (SIMO) systems. By exploiting the inherent symmetry of the underlying optimal Bayesian STE solution, a novel symmetric radial basis function (RBF) based STE scheme is proposed, which is capable of approaching the optimal Bayesian equalisation performance. Adaptive implementation of this symmetric RBF (SRBF) based STE can be achieved conveniently by estimating the SIMO channels using the least mean square channel estimator and computing the optimal RBF centres from the resulting SIMO channel matrix estimate. Simulation results also demonstrate that the performance of this SRBF based STE is robust with respect to the choice of the RBF variance value. The proposed adaptive solution is then extended to the space-time decision feedback equalisation (ST-DFE) structure.
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analysis of serial search based code acquisition in the Multiple transmit Multiple Receive Antenna aided ds cdma downlink
IEEE Transactions on Vehicular Technology, 2008Co-Authors: Lajos HanzoAbstract:In this paper, we investigate the serial-search-based initial code-acquisition performance of direct-sequence code division Multiple access (DS-CDMA) employing Multiple transmit/Multiple Receive Antennas when communicating over uncorrelated Rayleigh channels. We characterize the associated performance trends as a function of the number of Antennas. It is demonstrated that, in contrast to our expectation, the achievable correct-detection probability degrades in our typical target operational range as the number of transmit Antennas is increased. When maintaining a given total transmit power, our findings suggest that increasing the number of transmit Antennas results in the combination of the low-energy noise-contaminated signals of the transmit Antennas, which ultimately increases the mean acquisition time (MAT). However, it is extremely undesirable to increase the MAT when the system is capable of attaining its target bit-error-ratio performance at reduced signal-power levels, as a benefit of employing Multiple transmit Antennas.
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Iterative Spreading-Sequence Acquisition in the Multiple Receive Antenna Aided DS-UWB Downlink
2008 IEEE 68th Vehicular Technology Conference, 2008Co-Authors: Lajos HanzoAbstract:In this paper we investigate an iterative message passing (MP) aided Pseudonoise (PN) sequence acquisition scheme employing both beneficially selected generator polynomials (GPs) and Multiple Receive Antennas in the direct sequence-ultra wideband (DS-UWB) downlink (DL). The performance of this iterative acquisition scheme is analysed in terms of the achievable correct detection probability. Our scheme leads to an improved correct detection performance over an extended coverage area.
See-may Phoong - One of the best experts on this subject based on the ideXlab platform.
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EUSIPCO - Zero-forcing equalization of space-time block coded transmissions over frequency selective channels
2007Co-Authors: Yuan-hwui Chung, See-may PhoongAbstract:Recently, a polyphase approach was proposed for the analysis of space-time block coded (STBC) transmissions over frequency selective channels. Using this approach, we study the zero-forcing (ZF) equalization of these systems. In this study, we consider only the two transmit Antennas case. For the Receiver, the single and Multiple Receive Antennas cases are both considered. For the case of single Receive Antenna, the ZF Receiver is a unique infinite impulse response (IIR) filter whereas for the case of Multiple Receive Antenna, there exist finite impulse response (FIR) ZF Receivers. We will derive the general form of the ZF Receiver. Then the optimal ZF solution that minimizes the output noise variance will be derived. Simulation results show that the performance of STBC system with two transmit and one Receive Antenna is better than the conventional system with one transmit and one Receive Antenna. When there are Multiple Receive Antennas, it is found that there can be significant improvement if we optimize the ZF Receiver.
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Zero-forcing equalization of space-time block coded transmissions over frequency selective channels
2007 15th European Signal Processing Conference, 2007Co-Authors: Yuan-hwui Chung, See-may PhoongAbstract:Recently, a polyphase approach was proposed for the analysis of space-time block coded (STBC) transmissions over frequency selective channels. Using this approach, we study the zero-forcing (ZF) equalization of these systems. In this study, we consider only the two transmit Antennas case. For the Receiver, the single and Multiple Receive Antennas cases are both considered. For the case of single Receive Antenna, the ZF Receiver is a unique infinite impulse response (IIR) filter whereas for the case of Multiple Receive Antenna, there exist finite impulse response (FIR) ZF Receivers. We will derive the general form of the ZF Receiver. Then the optimal ZF solution that minimizes the output noise variance will be derived. Simulation results show that the performance of STBC system with two transmit and one Receive Antenna is better than the conventional system with one transmit and one Receive Antenna. When there are Multiple Receive Antennas, it is found that there can be significant improvement if we optimize the ZF Receiver.
Ye Li - One of the best experts on this subject based on the ideXlab platform.
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Iterative and Diversity Techniques for Uplink MC-CDMA Mobile Systems With Full Load
IEEE Transactions on Vehicular Technology, 2008Co-Authors: Y. Yuan-wu, Ye LiAbstract:Iterative and diversity techniques are two of the most effective techniques for uplink multicarrier code-division Multiple-access (MC-CDMA) systems. However, there is still no knowledge on how to efficiently combine these techniques to design high-performance uplink Receivers when there is a complexity constraint. In this paper, we compare the performance and the complexity of MC-CDMA systems with and without iterative detectors and Multiple-Receive-Antenna arrays. Through extensive simulation, we demonstrate that the following four combinations are good tradeoffs between complexity and performance: a single-Antenna Receiver with an iterative parallel-interference-cancellation (PIC) detector initialized by a matched filter (MF) with three iterations, a two-Antenna Receiver with a minimum-mean-square-error multiuser detector or an iterative PIC detector initialized by an MF with two iterations, and a four-Antenna Receiver with a simple MF detector. Therefore, noniterative detectors with Multiple-Receive-Antenna arrays can be used to replace iterative detectors and reduce complexity, which is a promising solution for fourth-generation (4G) uplink MC-CDMA systems, where Multiple-Receive Antennas are available at the base stations. In this paper, we also briefly discuss pilot-aided channel estimation using the weighted-delay-profile technique and investigate the impact of channel-estimation error in different environments.
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How to obtain good performance by iterative and diversity techniques for uplink MC-CDMA systems
2006 IEEE 63rd Vehicular Technology Conference, 2006Co-Authors: Y. Yuan-wu, M. Sarkiss, Ye LiAbstract:This paper aims at the system design on the MC-CDMA uplink. In this paper, we compare the performance and the complexity of MC-CDMA systems with and without iterative detectors and Multiple Receive Antenna arrays. Through extensive computer simulation, we demonstrate that the following four combinations are good solutions: a single-Antenna Receiver with an iterative PIC detector initialized by the MF and with 3 iterations, a two-Antenna Receiver with MMSE-MUD or an iterative PIC detector initialized by the MF and with 2 iterations, and a four-Antenna Receiver with a simple MF detector. Therefore, non-iterative detectors can be used with Multiple Receive Antenna arrays to substitute complicated iterative detectors and it is a promising solution for the 4G up-link MC-CDMA systems where Multiple Receive Antennas are available. In this paper, we have also considered pilot-aided channel estimation with weighted delay profile technique and investigated the impact of channel estimation error on different systems
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VTC Spring - How to obtain good performance by iterative and diversity techniques for uplink MC-CDMA systems
2006 IEEE 63rd Vehicular Technology Conference, 2006Co-Authors: Y. Yuan-wu, M. Sarkiss, Ye LiAbstract:This paper aims at the system design on the MC-CDMA uplink. In this paper, we compare the performance and the complexity of MC-CDMIA systems with and without iterative detectors and Multiple Receive Antenna arrays. Through extensive computer simulation, we demonstrate that the following four combinations are good solutions: a single-Antenna Receiver with an iterative PIC detector initialized by the MF and with 3 iterations, a two-Antenna Receiver with MMSE-MUD or an iterative PIC detector initialized by the MF and with 2 iterations, and a four-Antenna Receiver with a simple MF detector. Therefore, non-iterative detectors can be used with Multiple Receive Antenna arrays to substitute complicated iterative detectors and it is a promising solution for the 4G up-link MC-CDMA systems where Multiple Receive Antennas are available. In this paper, we have also considered pilot-aided channel estimation with weighted delay profile technique and investigated the impact of channel estimation error on different systems.
Sheng Chen - One of the best experts on this subject based on the ideXlab platform.
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adaptive bayesian space time equalisation for Multiple Receive Antenna assisted single input Multiple output systems
Digital Signal Processing, 2008Co-Authors: Sheng Chen, Lajos HanzoAbstract:This contribution considers nonlinear space-time equalisation (STE) for Multiple Receive-Antenna induced single-input Multiple-output (SIMO) systems. By exploiting the inherent symmetry of the underlying optimal Bayesian STE solution, a novel symmetric radial basis function (RBF) based STE scheme is proposed, which is capable of approaching the optimal Bayesian equalisation performance. Adaptive implementation of this symmetric RBF (SRBF) based STE can be achieved conveniently by estimating the SIMO channels using the least mean square channel estimator and computing the optimal RBF centres from the resulting SIMO channel matrix estimate. Simulation results also demonstrate that the performance of this SRBF based STE is robust with respect to the choice of the RBF variance value. The proposed adaptive solution is then extended to the space-time decision feedback equalisation (ST-DFE) structure.
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Symmetric Radial Basis Function Assisted Space-Time Equalisation for Multiple Receive-Antenna Aided Systems
2007 IEEE 66th Vehicular Technology Conference, 2007Co-Authors: Sheng Chen, Lajos HanzoAbstract:This constribution considers nonlinear space-time equalisation (STE) designed for single-input Multiple-output (SIMO) systems. By exploiting the inherent symmetry of the underlying optimal Bayesian STE solution, a novel symmetric radial basis function (RBF) based STE scheme is proposed, which is capable of achieving the optimal Bayesian equalisation performance. The adaptive adjustment of the STE taps of this symmetric RBF (SRBF) based STE can be achieved by estimating the SIMO channel encountered using the classic least mean square channel estimator and computing the optimal RBF centres from the resultant SIMO channel matrix estimate. Our simulation results demonstrate that the performance of this SRBF based STE is robust with respect to the choice of the algorithmic parameters.
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Minimum bit-error rate design for space-time equalization-based multiuser detection
IEEE Transactions on Communications, 2006Co-Authors: Sheng Chen, A. Livingstone, L. HanzoAbstract:A novel minimum bit-error rate (MBER) space-time-equalization (STE)-based multiuser detector (MUD) is proposed for Multiple-Receive-Antenna-assisted space-division Multiple-access systems. It is shown that the MBER-STE-aided MUD significantly outperforms the standard minimum mean-square error design in terms of the achievable bit-error rate (BER). Adaptive implementations of the MBER STE are considered, and both the block-data-based and sample-by-sample adaptive MBER algorithms are proposed. The latter, referred to as the least BER (LBER) algorithm, is compared with the most popular adaptive algorithm,known as the least mean square (LMS) algorithm. It is shown that in case of binary phase-shift keying, the computational complexity of the LBER-STE is about half of that required by the classic LMS-STE. Simulation results demonstrate that the LBER algorithm performs consistently better than the classic LM Salgorithm, both in terms of its convergence speed and steady-state BER performance.
Yuan-hwui Chung - One of the best experts on this subject based on the ideXlab platform.
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EUSIPCO - Zero-forcing equalization of space-time block coded transmissions over frequency selective channels
2007Co-Authors: Yuan-hwui Chung, See-may PhoongAbstract:Recently, a polyphase approach was proposed for the analysis of space-time block coded (STBC) transmissions over frequency selective channels. Using this approach, we study the zero-forcing (ZF) equalization of these systems. In this study, we consider only the two transmit Antennas case. For the Receiver, the single and Multiple Receive Antennas cases are both considered. For the case of single Receive Antenna, the ZF Receiver is a unique infinite impulse response (IIR) filter whereas for the case of Multiple Receive Antenna, there exist finite impulse response (FIR) ZF Receivers. We will derive the general form of the ZF Receiver. Then the optimal ZF solution that minimizes the output noise variance will be derived. Simulation results show that the performance of STBC system with two transmit and one Receive Antenna is better than the conventional system with one transmit and one Receive Antenna. When there are Multiple Receive Antennas, it is found that there can be significant improvement if we optimize the ZF Receiver.
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Zero-forcing equalization of space-time block coded transmissions over frequency selective channels
2007 15th European Signal Processing Conference, 2007Co-Authors: Yuan-hwui Chung, See-may PhoongAbstract:Recently, a polyphase approach was proposed for the analysis of space-time block coded (STBC) transmissions over frequency selective channels. Using this approach, we study the zero-forcing (ZF) equalization of these systems. In this study, we consider only the two transmit Antennas case. For the Receiver, the single and Multiple Receive Antennas cases are both considered. For the case of single Receive Antenna, the ZF Receiver is a unique infinite impulse response (IIR) filter whereas for the case of Multiple Receive Antenna, there exist finite impulse response (FIR) ZF Receivers. We will derive the general form of the ZF Receiver. Then the optimal ZF solution that minimizes the output noise variance will be derived. Simulation results show that the performance of STBC system with two transmit and one Receive Antenna is better than the conventional system with one transmit and one Receive Antenna. When there are Multiple Receive Antennas, it is found that there can be significant improvement if we optimize the ZF Receiver.
