We investigate the interference management strategy for multiuser two-way transmission network where multiple pairs of users communicate with their pre-assigned partners, with assistance of an amplify-and-forward rela...
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We investigate the interference management strategy for multiuser two-way transmission network where multiple pairs of users communicate with their pre-assigned partners, with assistance of an amplify-and-forward relay. The design objective is that the tradeoff between the efficiency and reliability could be achieved as much as possible. By taking advantage of the signal space alignment technique to cancel the multi-user interference, all users can transmit massages to the relay simultaneously over the same channel resource. And a new multiple-input multiple-output (MIMO) precoding matrix is designed to reduce the decoding complexity. Simulation result shows the average sum rate performance of the proposed system, and the achievable degrees of freedom can outperform MU-MIMO scheme and TDMA scheme.
A multiple relay selection system model that implements the decode-and-forward mode is investigated. All communication nodes are assumed to be equipped by multiple antennas. Furthermore, lattices space-time coded mult...
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A multiple relay selection system model that implements the decode-and-forward mode is investigated. All communication nodes are assumed to be equipped by multiple antennas. Furthermore, lattices space-time coded multiple-input multiple-output half duplex channel is applied. The main goal is to increase the throughput of the system by selecting multiple number of relays. The selection criteria depends on the maximum decoding delay at relays where the system implements a decoding time-out algorithm at each relay. This leads to a significant saving in the overall system power consumptions and attempts to solve the relays synchronization problem. All results are presented using numerical simulations.
A novel coherent optical multiple-input multiple-output architecture is proposed for wireless communication links to mitigate atmospheric turbulence effects. Transmitter optical signals operate at distinct carrier fre...
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ISBN:
(纸本)9781467300094
A novel coherent optical multiple-input multiple-output architecture is proposed for wireless communication links to mitigate atmospheric turbulence effects. Transmitter optical signals operate at distinct carrier frequencies to allow the received optical signals to be separately processed. The accumulated phase noise in each transmission branch can be independently compensated electronically. Based on the proposed architecture, several popular diversity combining techniques are considered for system performance evaluation. The presented results demonstrate substantial error performance improvement over a single-input single-output coherent optical wireless link.
In multiple-input multiple-output radar, independent waveforms are transmitted from different antennas, and the target parameters are estimated via the linearly independent echoes from different targets. Several adapt...
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ISBN:
(纸本)9781479925650
In multiple-input multiple-output radar, independent waveforms are transmitted from different antennas, and the target parameters are estimated via the linearly independent echoes from different targets. Several adaptive approaches are directly applied to target angle and target amplitude estimation, including Capon, APES (amplitude and phase estimation). The CCA (canonical correlation analysis) approach is first proposed to estimate target locations which has high peak amplitudes, then a gradient-based algorithm is presented to improve the target angle estimation accuracy based on Capon approach which has a high resolution. With an initial angle, the angle sequence is iteratively updated with adaptive steps and converges to local peaks which indicate the target locations. Simulations show that the target angle accuracy is improved, and the common DOA (direction-of-arrive) problem is avoided.
In this paper a novel decoupling method using eigenmode derived from S-parameter is proposed. Eigen beam forming toward a degenerated eigenmode of a mutual coupling channel allows one antenna group to be isolated from...
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ISBN:
(纸本)9781479910861;9781479910885
In this paper a novel decoupling method using eigenmode derived from S-parameter is proposed. Eigen beam forming toward a degenerated eigenmode of a mutual coupling channel allows one antenna group to be isolated from the other spatially, which results in decoupling over a wide range of frequencies. Moreover, due to symmetric antenna arrangement, the proposed method can isolate one antenna group from many more antennas.
In this letter, we report the performance of multi-user transmitter pre-processing (MUTP) assisted multiple-input multiple-output downlink (DL) communication, when the channel state information (CSI) required to formu...
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ISBN:
(纸本)9781467348669;9781467348652
In this letter, we report the performance of multi-user transmitter pre-processing (MUTP) assisted multiple-input multiple-output downlink (DL) communication, when the channel state information (CSI) required to formulate the preprocessing matrix is estimated at the receiver and fed back to the base station (BS) through feedback channels that experience noise. In particular, in our work the CSIs are estimated at the mobile stations (MSs) and the estimated CSIs (ECSIs) are decomposed by invoking singular value decomposition. The signal space of right-hand side unitary matrix of the decomposed ECSI associated with each of the MSs is then vector quantized and the magnitudes and phases are communicated to the BS as channel spatial information through noisy feedback channels. This vector quantized channel spatial information which is tainted by noise is recovered by employing minimum mean square error based linear detector. The recovered spatial information is then utilized to conceive the pre-processing matrix to deal with the DL multi-user interference (MUI). Our study shows that, MUTP realized with perfect CSI at the BS is capable of completely eliminating the MUI. However, vector quantized channel spatial information based MUTP results in imperfect removal of MUI, as the quantization errors and feedback channel induced errors play a principal role in determining its performance in the context of interference removal. Albeit the achievable symbol error rate (SER) slightly degrades compared to the perfect CSI case, we advocate that vector quantization seems to be an efficient approach in quantizing the necessary spatial information and feeding them back to the BS for the purpose of formulating the pre-processing matrix particularly in frequency division duplex aided wireless systems.
An efficient and high-performance semi-blind scheme is proposed for multiple-input multiple-output (MIMO) systems by iteratively combining channel estimation with K-Best Sphere Decoding (SD). To avoid the exponentiall...
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ISBN:
(纸本)9781479915019
An efficient and high-performance semi-blind scheme is proposed for multiple-input multiple-output (MIMO) systems by iteratively combining channel estimation with K-Best Sphere Decoding (SD). To avoid the exponentially increasing complexity of Maximum Likelihood Detection (MLD) while achieving a near optimal MLD performance, K-best SD is considered to accomplish data detection. Semi-blind iterative estimation is adopted for identifying the MIMO channel matrix. Specifically, a training-based least squares channel estimate is initially provided to the K-best SD data detector, and the channel estimator and the data detector then iteratively exchange information to perform the decision-directed channel update and consequently to enhance the detection performance. The proposed scheme is capable of approaching the ideal detection performance obtained with the perfect MIMO channel state information.
Sphere Decoder (SD) is widely being used in multipleinputmultipleoutput (MIMO) systems to reduce the complexity of the system while obtaining near Maximum Likelihood (ML) performance. The complexity of the system i...
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ISBN:
(纸本)9781479921041
Sphere Decoder (SD) is widely being used in multipleinputmultipleoutput (MIMO) systems to reduce the complexity of the system while obtaining near Maximum Likelihood (ML) performance. The complexity of the system increases with the increase in antenna configuration or the constellation size. Some pre-processing is a fundamental prerequisite in iterative detectors to reduce the system complexity by focusing the received signal energy to reduce the effect of inter-symbol interference. The QR Decomposition (QRD) of communication channel matrices in the pre-processor stage is an important issue to ensure good performance of the subsequent steps of decoding thus a QRD) is commonly used in many MIMO detection algorithms. A sorted QR decomposition (SQRD) is an advanced algorithm that improves the performance of MIMO detection. In this paper the efficiency of QRD and SQRD methods in terms of computational complexity, error rate performance and the FPGA resources utilized is presented. The main contribution of this work is a comparison of hardware implementations of the QRD and SQRD system. QRD for 4x4 MIMO system is implemented on various target FPGA platforms to compare their area utilization.
Automatic modulation classification (AMC) of unknown communications signals is employed in both commercial and military applications, such as cognitive radio, spectrum surveillance, and electronic warfare. Most of the...
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ISBN:
(纸本)9781467329323;9781467329293
Automatic modulation classification (AMC) of unknown communications signals is employed in both commercial and military applications, such as cognitive radio, spectrum surveillance, and electronic warfare. Most of the AMC methods proposed in the literature are developed for systems with a single transmit antenna. In this paper, an AMC algorithm for multiple-input multiple-output (MIMO) signals is proposed, which is based on higher-order cumulants. The use of cumulants with different orders, as well as their combinations as feature vectors are investigated. The ideal case of a priori knowledge of the channel state information (CSI) is considered, along with a setting of practical relevance, where the channel matrix is blindly estimated through independent component analysis. The performance of the proposed algorithm with different features is evaluated through simulations and compared with that of the average likelihood ratio test (ALRT).
We demonstrate wavelength-division multiplexed (WDM) and mode-division multiplexed (MDM) transmission over a fiber recirculating loop comprising of a 25-km span of low differential mode group dispersion (DMGD) few-mod...
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ISBN:
(纸本)9780819494160
We demonstrate wavelength-division multiplexed (WDM) and mode-division multiplexed (MDM) transmission over a fiber recirculating loop comprising of a 25-km span of low differential mode group dispersion (DMGD) few-mode fiber carrying the LP01 and LP11 mode groups, and an inline few-mode erbium-doped fiber amplifier (FM-EDFA) providing low mode-dependent gain (MDG) per span. We successfully transmitted a 10 lambda x 6 x 28-Gbaud QPSK signal over a distance of 700 km.
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