Rapid development of wireless services, leads to ubiquitous personal connectivity in the world. The demand for multimedia interactivity is higher in the world which leads to the requirement of high data transmission r...
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This study develops a feature-based Automatic Modulation Classification (AMC) algorithm for spatially multiplexed multiple-input multiple-output (MIMO) systems employing two Higher Order Cumulants (HOCs) of the estima...
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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.
In this paper, we investigate an indoor multiuser visible light communication system employing multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM). For each subcarrier in OFDM, the ...
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ISBN:
(纸本)9781479975921
In this paper, we investigate an indoor multiuser visible light communication system employing multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM). For each subcarrier in OFDM, the corresponding precoding matrix is calculated in the frequency domain to eliminate multi-user interference. The distances of the multiple transmitter-receiver links are different, which results in various temporal delays and phase differences in the frequency domain. Phase information is firstly considered, whereby complex instead of real channel matrices are used for precoding, which reduces the channel correlation and achieves better performance. Moreover, two DC bias and scaling factor calculation schemes are proposed, and their performances are compared with zero forcing and minimum mean-squared error (MMSE) precoding techniques.
In this paper, we propose a novel codebook-based precoding design for orthogonal space-time block codes (OSTBCs) over multiple-input multiple-output (MIMO) channels with finite rate feedback. The proposed approach aim...
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In this paper, we propose a novel codebook-based precoding design for orthogonal space-time block codes (OSTBCs) over multiple-input multiple-output (MIMO) channels with finite rate feedback. The proposed approach aims at providing better system performance by utilizing the property of OSTBCs and the prior information of the statistical antenna correlation. Under a new way of controlling the average transmit power, a novel structure of precoding matrix is given, which is different from the unitary precoding. Moreover, with the information of the transmit correlation matrix, the codebook design is generalized to correlated channels. Both theoretical analyses and simulation results are provided.
Orthogonal space-time block coding (STBC) offers linear-complexity one-shot maximum-likelihood (ML) reception when the channel coefficients are known to the receiver. However, when the channel coefficients are unknown...
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ISBN:
(纸本)9781424429257
Orthogonal space-time block coding (STBC) offers linear-complexity one-shot maximum-likelihood (ML) reception when the channel coefficients are known to the receiver. However, when the channel coefficients are unknown, the optimal receiver takes the form of sequence detection. In this work, we prove that ML noncoherent sequence detection can always be performed in polynomial time with respect to the block length for orthogonal STBC and Rayleigh distributed channel coefficients. Using recent results on efficient maximization of reduced-rank quadratic forms over finite alphabets, we develop a novel algorithm that performs ML noncoherent orthogonal STBC detection with polynomial complexity in the block length. The order of the polynomial complexity of the proposed receiver is determined by the number of transmit and receive antennas.
In multiple-input multiple-output (MIMO) communication systems, complex matrix inversion is a very computationally demanding operation. Especially when the number of antennas increases, i.e., in a massive MIMO system,...
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ISBN:
(纸本)9781467376884
In multiple-input multiple-output (MIMO) communication systems, complex matrix inversion is a very computationally demanding operation. Especially when the number of antennas increases, i.e., in a massive MIMO system, the complexity of matrix inversion becomes very high. Motivated by this observation, a new low complexity complex matrix inversion method, called SDF-SGR (Square root and Division Free Squared Givens' Rotations) based algorithm, is designed for MIMO channels. Square root operation is avoided in the whole algorithm, and division operation is replaced by shift operation during the Givens' rotations phase. Besides, since the scale factor z, involved in the traditional SGR, has little influence on the whole algorithm, it is removed in this SDF-SGR algorithm. Considering a 4×4 complex matrix inversion, the SDF-SGR based algorithm could reduce the multiplication operations by 13.07% compared with the traditional SGR algorithm, and the division operation is reduced by almost 52.94%.
In this letter, we report the performance of multiuser transmitter pre-processing (MUTP) assisted multiple-input multiple-output downlink (DL) communication, when the channel state information (CSI) required to formul...
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ISBN:
(纸本)9781467348652
In this letter, we report the performance of multiuser 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.
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