Low-complexity minimum-mean-square error (MMSE)-based integrated equalisation (IEQ) for multiple-inputmultiple-output (MIMO) systems with hybrid automatic repeat request (HARQ) is proposed. In the proposed MMSE-based...
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Low-complexity minimum-mean-square error (MMSE)-based integrated equalisation (IEQ) for multiple-inputmultiple-output (MIMO) systems with hybrid automatic repeat request (HARQ) is proposed. In the proposed MMSE-based IEQ, the calculations of the MMSE filtering vector for each symbol in the conventional MMSE-based IEQ are newly derived in a simplified form. This not only allows the proposed IEQ to have the same MMSE filtering vector to the conventional IEQ but it also allows the matrix size to be inverted and the number of matrix inversions are also significantly decreased. Therefore, without sacrificing the error performance, the proposed IEQ requires a significantly lower computational complexity than the conventional IEQ as the number of inputs increases. Furthermore, the proposed IEQ can outperform the MMSE-based iterative equalisation with the log-likelihood ratio-level combining in terms of both error performance and computational complexity.
Orthogonal Space-Time Block Codes (STBC) with multiple-inputmultiple-output (MIMO) systems have become a very popular way of adding spatial diversity to transmissions. Orthogonal Frequency Division multiplexing (OFDM...
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ISBN:
(纸本)9781479967704
Orthogonal Space-Time Block Codes (STBC) with multiple-inputmultiple-output (MIMO) systems have become a very popular way of adding spatial diversity to transmissions. Orthogonal Frequency Division multiplexing (OFDM) is a modulation technique to further increase the robustness against frequency selective fading at high data rates. Some authors have then proposed to combine both: linear STBC codes with OFDM;however, with a major weakness: high Peak to Average Power Ratio (PAPR). Using instead Continuous Phase Modulation (CPM) to get constant envelope signals to reduce PAPR, CPM-OFDM can take advantage of a favorable trade-off between power and bandwidth efficiency given by CPM with the well-known robustness to frequency selective fading of OFDM. To further increase the data throughput, while maintaining robustness to frequency selective fading and low PAPR, we introduce here a new space-time-frequency diversity technique based on MIMO OFDM using L2-orthogonal multi-h CPM STBC codes. We benchmark these schemes under Rayleigh frequency selective channels with semi-coherent detection and show how they achieve improved spectral compactness while providing a low decoding complexity by the use of a simplified Zero-Forcing (ZF) detection/ correlation algorithm.
Sphere decoding (SD) is a promising means for implementing high-performance data detection in multiple-inputmultiple-output (MIMO) wireless communication systems. In this paper, we focus on the register transfer leve...
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ISBN:
(纸本)9781424464708
Sphere decoding (SD) is a promising means for implementing high-performance data detection in multiple-inputmultiple-output (MIMO) wireless communication systems. In this paper, we focus on the register transfer level implementation of SD with minimum area-delay product for application in wideband MIMO communication systems, such as IEEE 802.11n, where multiple SD cores need to be instantiated. The basic architectural considerations and the proposed optimizations are explained based on hard-output SD, but are also applicable to soft-output SD. Corresponding VLSI implementation results (for both hard-output and soft-output SD) show an improvement in the area-delay product by almost 50% compared to that of other SD implementations reported in the literature.
This paper deals with the localization of passive stationary objects from the received radio-frequency (RF) signals in 3-dimensional (3D) indoor environments. Each object located in the 3D indoor environment is modell...
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ISBN:
(纸本)9781728112206
This paper deals with the localization of passive stationary objects from the received radio-frequency (RF) signals in 3-dimensional (3D) indoor environments. Each object located in the 3D indoor environment is modelled by a single point scatterer. The propagation space is equipped with a multiple-inputmultiple-output (MIMO) wireless communication system. The employed channel model is flexible and allows to have a line-of-sight (LOS) component as well as single- and double-bounce scattering components. Here, we present a new accurate iterative estimation technique for computing the optimal coordinates as well as the number of the main stationary objects (scatterers) in indoor areas. The proposed approach aims at matching the frequency correlation function (FCF) of the transfer function (TF) of the received RF signals to the FCF of the channel model. This iterative procedure is based on numerical optimization techniques to estimate the number and coordinates of the scatterers and the channel parameters by minimizing the Euclidean norm of the fitting error. Numerical results are presented to confirm the accuracy of the proposed estimation procedure by comparing the estimated positions as well as the resulting FCF with the corresponding exact quantities, known from generated RF signals.
The use of multiple-inputmultiple-output (MIMO) systems has been a central part of cellular systems for achieving higher capacity. Distributed antenna system (DAS) is a MIMO system with geographically distributed ant...
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ISBN:
(纸本)9781479974986
The use of multiple-inputmultiple-output (MIMO) systems has been a central part of cellular systems for achieving higher capacity. Distributed antenna system (DAS) is a MIMO system with geographically distributed antennas that provide high coverage and capacity due to the spatial macro diversity. In a multi-user scenario, DAS provides better spatial separation among users. An optimal transmission strategy in a multiuser multi-cell DAS is unknown. We analyze and evaluate downlink capacity of three multiplexing strategies: orthogonal transmission, joint precoding, and space division multiplexing (SDM). Based on the evaluation we propose the most appropriate strategy. The sum-rate has been measured in different scenarios. Simulation results show that DAS has superior performance compared to co-located antennas systems (CAS). It is particularly shown that DAS with simple SDM can provide better capacity than joint transmission in addition to reduced complexity and less feedback overhead. This happens when the number of users increases and remote radio units have single antenna.
Orthogonal Frequency Division multiplexing (OFDM) is a popular modulation technique that provides high data rates and good robustness against frequency selective fading. Space-Time Block Coding (STBC) is an efficient ...
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ISBN:
(纸本)9781479971626
Orthogonal Frequency Division multiplexing (OFDM) is a popular modulation technique that provides high data rates and good robustness against frequency selective fading. Space-Time Block Coding (STBC) is an efficient way to introduce space-time diversity in multiple-inputmultiple-output (MIMO) systems. Using non-linear modulations such as Continuous Phase Modulation (CPM) with its constant envelope and continuous phase properties could be a solution to construct MIMO OFDM systems and to avoid the structural limitations of linear codes and alleviate the typical PAPR issue of OFDM. However, a major issue with CPM based systems may remain: the decoding complexity. In this paper, we introduce a new space-time-frequency diversity technique based on L2-orthogonal multi-h CPM Space-Time codes designed for OFDM transmission. We benchmark these codes under Rayleigh frequency selective channels and show how they achieve full spatial diversity at full rate for any number of antennas, good spectral compactness and also robustness to frequency fading. Furthermore, the decoding complexity is highly reduced and even made linear in the number of antennas thanks to the orthogonality properties.
multiple-inputmultiple-output (MIMO) techniques are now being commonplace in wireless communication systems as they provide diversity and spatial multiplexing gains compared to single-input single-output (SISO) syste...
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ISBN:
(纸本)9781509017492
multiple-inputmultiple-output (MIMO) techniques are now being commonplace in wireless communication systems as they provide diversity and spatial multiplexing gains compared to single-input single-output (SISO) systems. Due to the induced high complexity of maximum likelihood (ML) detection for MIMO systems, suboptimal detection is usually employed but at a performance loss. This loss has been fully characterized for linear receivers, namely, zero-forcing (ZF) and minimum mean square error (MMSE) detectors. Interestingly, it has been noticed that in case of coding across transmit antennas, the MMSE receiver showed significant improvement over ZF in terms of outage probability at low spectral efficiencies, whereas for high spectral efficiencies, both receivers showed similar behaviour. We fill the gap between the two extreme cases (i.e., ML and linear receivers) through relaxing the linearity constraint by considering group receivers (viz. group zero-forcing (GZF) and group minimum mean square error (GMMSE) detectors) with coding across transmit antennas. We first derive the diversity-multiplexing tradeoff (DMT) for those group detectors. Next, we characterize the peculiar rate-dependent outage behaviour of the GMMSE, where it is found that tolerating additional detection complexity provides performance advantage w.r.t the MMSE at specific ranges of spectral efficiency. We corroborate our theoretical analysis via numerical simulations.
In recent times, the research community has shown significant interest in "Millimeter Wave (mmWave)" communication. Specifically, within the context of "Fifth Generation (5G) wireless networks", mm...
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ISBN:
(纸本)9798350395334;9798350395327
In recent times, the research community has shown significant interest in "Millimeter Wave (mmWave)" communication. Specifically, within the context of "Fifth Generation (5G) wireless networks", mmWave "Massive multiple-inputmultiple-output (MIMO)" communications are implemented using hybrid transceivers. In this survey, machine structure algorithms have been raised as trustable solutions over the past decennary. These algorithms offer the potential to tackle complex optimization problems within MIMO systems effectively. This review explains the recent modern deep structure and machine learning applications in the broad field of beamforming. The efficiency of wireless transmission is done by modifying the strength of the signal. Here, the brief introduction to the vector quantity of Beamforming and the selection of antenna in the MIMO sector and its existing literature works are presented elaborately. This review helps readers to understand the latest deep learning and machine learning technologies used for beamforming in MIMO systems. A detailed description from various perspectives on the antenna structures like "phased array antennas" and diversity antennas and several Beamforming learning methodologies are analyzed. Further, it offers better future research guidance to fulfill the development requirements of flexible antennas for upcoming wireless fidelity.
In this paper, we propose a compensation method for the joint effect of high-power amplifier (HPA) nonlinearity, in-phase/quadrature-phase (I/Q) imbalance and crosstalk in multiple-inputmultiple-output (MIMO) orthogo...
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ISBN:
(纸本)9781457713484
In this paper, we propose a compensation method for the joint effect of high-power amplifier (HPA) nonlinearity, in-phase/quadrature-phase (I/Q) imbalance and crosstalk in multiple-inputmultiple-output (MIMO) orthogonal space-time block coding (OSTBC) systems. The performance of the MIMO OSTBC equipped with the proposed compensation mechanism is evaluated in terms of average symbol error probability and system capacity, in Rayleigh fading channels. Numerical results are provided and show the effects on performance of several system parameters, namely, the HPA parameters, image-leakage ratio, crosstalk, numbers of antennas, and phase-shift keying modulation order.
In this paper, we derive user selection criteria based on the error probability for an actually employed detector for multiuser multiple-inputmultiple-output (MIMO) systems. We propose a low complexity sequential use...
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ISBN:
(纸本)9781424456383
In this paper, we derive user selection criteria based on the error probability for an actually employed detector for multiuser multiple-inputmultiple-output (MIMO) systems. We propose a low complexity sequential user selection scheme when a lattice reduction (LR) based MIMO detector is used. We also analyze the diversity gain for combinatorial user selection approaches with a given LR-based detector. From simulation results, we can confirm that the proposed sequential user selection approach can provide a comparable performance to the combinatorial ones with much lower complexity.
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