Multiple-input Multiple-output Modulation Research Articles

Successive Interference Analysis for 5G System at Mid-Band and High-Band Frequency

This research study focuses on the impact of interference on different 5G system parameters such as modulation techniques (64-QAM, 256-QAM), channel models (AWGN, Rayleigh, and Rician), and MIMO (multiple input, multiple output) in terms of Bit Error Rate (BER). After the analysis of interference for each parameter, an analysis of interference by Short Range Devices (SRDs) on the 5G system network on the downlink channel is done. Finally, successive interference cancellation (SIC) for a 5G Non-Orthogonal Multiple Access (NOMA) system with Power Division Multiplexing (PDM) is applied. A 5G NOMA has higher spectral efficiency as compared to an Orthogonal Frequency Division Multiple Access (OFDMA), so it can fulfil the needs of the Internet of Things (IoT). SIC is implemented using PDM, where each user is assigned a certain power factor and generates a signal, the generated signal is superimposed and the New-Radio (NR) transmitter that transmits the superimposed signal. Finally, the signal is detected with and without SIC on the access side with SRDs as an interferer. After simulation and analysis of different 5G system parameters, it is found that the BER is decreased with an increase in the MIMO and is more applicable to the higher order modulation. With the SIC, the BER for the NOMA users decreased as compared to OFDMA users. The power coefficients for the stronger signal user (user 1) and weaker signal user (user 2) are 0.25 and 0.75 respectively.

Adaptive Transmission Based on MIMO Mode Switching Over Malaga Turbulence Channel With Pointing Error

In this paper, we propose a dynamic adaptive multiple input multiple output (MIMO) free space optical (FSO) system with spatial mode switching. Based on the channel conditions, the proposed system can select different MIMO transmission modes: diversity, multiplexing or hybrid mode that yields the maximum average channel capacity while satisfying the reliable average bit error rate (BER). Considering the combined effects of path loss, pointing error and atmospheric turbulence-induced fading modeled by Malaga distribution, we derive the closed-form expressions of average channel capacity and average BER of MIMO system for each transmission mode. From adaptive system performance evaluated results, we establish the signal-to-noise ratio (SNR) threshold look-up table (LUT) in different scenarios to select the optimal transmission mode. The extensive numerical results demonstrate that the proposed adaptive system has a significant improvement in average channel capacity compared with each stand-alone mode system. Finally, Monte Carlo simulation is also provided to verify the correctness of the proposed adaptive scheme and conclusions.

A quad-port multiple-input-multiple-output system for underlay or interweave cognitive radio

<span lang="EN-US">This paper presents a four-element frequency reconfigurable antenna system that is novel in terms of gathering both underlay and interweave cognitive radio in a single multiple input, multiple output (MIMO) design. Built on a 50×38×0.8 mm3 Rogers RT/Duroid 5880 substrate, this system is constructed of two scanning elements to sense ultra-wide band (UWB) with controllable band notching capabilities and two elements act as communication antennas. Eighteen MIMO modes can be provided depending on the state of the five positive-intrinsic-negative (PIN) diodes in each sensing antenna and the four PIN diodes in each communication antenna. These include a scanning UWB mode, fourteen modes to notch WiMax/Cband/<a name="_Hlk120169348"></a>wireless local area network (WLAN)/Xband/ITU in single/dual/triple/quad band rejection states and three interweave modes where each targeting one of the regions of WiMax/Cband/WLAN. Simulated by CST v.10; results like input reflection coefficient and realized gain verify system's capability to work in each operation mode. Moreover, mutual coupling, envelope correlation coefficient and diversity gain all evidence the performance of the proposed system as a MIMO system. Results, simple and compact profile, wide and flexile range of MIMO operation modes in line with the novelty to handle both underlay and interweave cognitive radio all nominate this system as promising to fulfill the needs of modern wireless communications.</span>

An Artificial Intelligence-Assisted Expectation Propagation Detection for MIMO Systems

Multiple-input multiple-output (MIMO) technology is one of the key technical approaches to improve the spectrum efficiency of wireless communication. Modern communication systems employ MIMO and high-order quadrature amplitude modulation (QAM) to maximize spectral efficiency. However, with the increase in the number of antennas and modulation orders, it is very challenging to design a low-complexity and high-efficiency MIMO receiver. In recent years, with the rapid development of new technologies such as artificial intelligence, more and more researchers have tried to apply machine learning techniques in the field of communication to break through the performance of traditional communication algorithms. In this paper, we propose a new low-complexity MIMO detection algorithm: an artificial intelligence-assisted expectation propagation (EP) detection algorithm. Neural network models are used to learn and map some of the time-consuming steps in the EP detection algorithm, converting the complex operation process into a few matrix multiplication operations in order to reduce the complexity of the detection algorithm. It is verified that the method proposed in this paper can approximate the performance of the original EP detection algorithm with reduced complexity and is applicable in different scenarios.

Research on uplink performance of MIMO terrestrial-satellite laser communication based on OSM-MBM joint modulation

This paper proposes a multiple-input multiple-output (MIMO) terrestrial-satellite laser communication uplink system based on optical spatial modulation with medium-based modulation (OSM-MBM) joint modulation. The Málaga(M) distribution is used to describe the combined effects of near-ground turbulent light intensity scintillation, beam wander and angle of arrival fluctuation. The closed expression of the bit error rate (BER) of the OSM-MBM joint modulation MIMO terrestrial-satellite laser communication uplink is derived. The simulation analyzes the influence of transmitting radius, receiving aperture, beam divergence, zenith angle and signal-to-noise ratio on the system error performance, and compares it with traditional modulation, media-based modulation and optical space modulation. Finally, the experiment is verified by Monte Carlo. This research provides a theoretical reference for the engineering realization of the modulation technology for the MIMO terrestrial-satellite laser communication uplink system.

Приемник сигналов многоантенных систем связи с множественным доступом на основе разреженных кодов, основанный на QR-разложении

Methods of non-orthogonal multiple access are a promising group of techniques that allow increasing the noise immunity of communication and the number of network connections. One of the implementation techniques of this approach is sparse code multiple access (SCMA). The use of SCMA in conjunction with multiple-input multiple-output (MIMO) systems allows for a high level of noise immunity and spectral efficiency and can be a concept for organizing the physical layer of 6G networks. In this article we look at different MIMO-SCMA circuits and give the basic steps of signal formation and processing. One of the problems in implementing SCMA-MIMO is the high computational complexity of signal processing algorithms in the receiver. To solve this problem, we suggest using a method based on QR-decomposition. In the article, we demonstrate that this method makes it possible not only to reduce computational complexity by several times but also to provide higher noise immunity compared to classical approaches. The results are obtained for various MIMO configurations and modes. The proposed method can be used in promising communication systems of future generations.

Zero Forcing Assisted Single Layer Beamforming for Spatial Modulation MIMO Systems

A zero forcing (ZF) assisted single layer beamforming is developed for spatial modulation (SM) and space shift keying (SSK) modulation multiple input multiple output (MIMO) systems, termed as SZF-SM/SZF-SSK, to achieve both transmit beamforming and receive diversity gain in this paper. Specifically, the proposed SZF-SM/SZF-SSK maps part of the bits to spatial domain, simultaneously forming a ZF precoding assisted single layer data both in multiple input single output (MISO) and MIMO systems, that differs greatly from conventional ZF beamforming assisted MIMO systems. With MISO configuration, the ZF precoder of SZF-SM/SZF-SSK converges to the maximum ratio transmission (MRT), achieving only the transmit beamforming gain. With MIMO configuration, SZF-SM/SZF-SSK tranceiver could be further modified along with the MIMO channel to achieve single layer transmission and joint detection, attaining both the transmit beamforming and receive diversity gain in SM-MIMO system. The theoretical analysis and the simulation results of the proposed SZF-SM/SZF-SSK with MISO and MIMO configurations are presented in this paper respectively, which show an attractive performance gain over the conventional SM/SSK. Compared with the conventional ZF beamforming assisted MIMO systems and some other CSI assisted SM-MIMO schemes, the proposed scheme exhibits better performance, especially under highly correlated MIMO channels, rendering a new and practical way to achieve low rank MIMO transmission with good performance and high data rate.

Low Complexity Optimal and Suboptimal Detection at Spatial Modulation MIMO Receivers

This paper develops three low-complexity detection schemes for the spatial modulation (SM) Multiple Input Multiple Output (MIMO) systems. We first propose a reduced complexity maximum likelihood (RC-ML) detection scheme. For the practical values of the modulation index, the proposed RC-ML method is simpler than the existing hard-limiting-based ML schemes. The two other proposals are based on a suboptimal Maximum Ratio Combining (MRC) detection method. We present a new analysis of the MRC detector in the uncorrelated Rayleigh fading channel and identify the system operational scenarios for which the MRC performance is nearly identical to the ML performance. Our proposals — a hybrid MRC-ML method and an MRC scheme with rank reduction — are inspired by this analysis. The analytical and simulation results show that the proposed MRC-based schemes can attain a near-optimal performance while reducing the complexity of the ML-based SM receiver.

MIMO Radar Hardware Acceleration with Enhanced Resolution

This paper proposes a method for accelerating an enhanced resolution 3D (range, velocity, and azimuth) Multiple Input Multiple Output (MIMO) radar on a Graphics Processing Unit (GPU). Implementation of MIMO radars and the investigation of their performance are of interest to the research community. However, the MIMO mode of operation increases the computational requirements of the radar system and seldom permits real-time operation without performance compromises. Current methods for achieving reasonable frame rates include reducing the scope of the radar (i.e., limiting the number of dimensions, the field of view, or the ranges of interest), choosing efficient but coarse algorithms (i.e., the FFT for range, velocity, and bearing estimation), or offloading the computation on task specific hardware, DSP, or FPGA. The proposed framework enables real-time operation of the MIMO radar by performing the signal processing on a GPU without compromising the radar coverage, while replacing the widely used 3D FFT with an enhanced resolution alternative. The proposed framework is tested on a Frequency Modulated Continuous Wave (FMCW) MIMO radar using 8 transmitters, 8 receivers, and having a Coherent Processing Interval (CPI) of 256 chirps. The parallel implementation of the enhanced resolution signal processing yields an acceleration of 453.6x when compared to sequential execution on CPU.

Historical Development of Spatial Modulation and Massive MIMO Communication System with Implementation Challenges: A Review

: For wireless communication networks, massive MIMO (Multiple-Input Multiple- Output) technology has been considered a major achievement. MIMO Technology consists of equipping a base station with a large number of antennas to serve many active users. Through MIMO Technology, the ability to concentrate on transmitted signal energy in very short spaces would result in huge increases in system capacity. While this new concept provides some fascinating benefits, it creates a new tension that has drawn both academia and industry attention. Channel state information acquisition, channel feedback, instant reciprocity, statistical reciprocity, architecture and hardware impairments are few of them. This paper presents a survey on Spatially Modulated Massive MIMO's historical development.

SYMMeTRy: Exploiting MIMO Self-Similarity for Under-Determined Modulation Recognition

Modulation recognition (modrec) seeks to identify the modulation of a transmitter from coresponding spectrum scans. It is an essential functional component of future spectrum sensing with critical applications in dynamic spectrum access and spectrum enforcement. While predominantly studied in single-input single-output (SISO) systems, practical modrec for multiple-input multiple-output (MIMO) communications requires more research attention. Existing MIMO modrec impose stringent requirements of fully- or over-determined sensing front-end, i.e. the number of sensor antennas should exceed that at the transmitter. This poses a prohibitive sensor cost even for simple 2x2 MIMO systems and will severely hamper progress in flexible spectrum access. We design a MIMO modrec framework that enables efficient and cost-effective modulation classification for under-determined settings involving fewer sensor antennas than those used for transmission. Our key idea is to exploit the inherent multi-scale self-similarity of MIMO modulation IQ constellations, which persists in under-determined settings. Our framework, called SYMMeTRy (Self-similaritY for MIMO ModulaTion Recognition), designs domain-aware classification features with high discriminative potential by summarizing regularities of symbol co-location in the MIMO constellation. To this end, we summarize the fractal geometry of observed samples to extract discriminative features for supervised MIMO modrec. We evaluate SYMMeTRy in a realistic simulation and in a small-scale MIMO testbed. We demonstrate that it maintains high and consistent performance across various noise regimes, channel fading conditions and with increasing MIMO transmitter complexity. Our efforts highlight SYMMeTRy's high potential to enable efficient and practical MIMO modrec in spectrum sensing infrastructures with mixed-complexity sensors.

Transmit antenna selection for spatial modulation MIMO IoT networks with full-duplex relaying

Recent advances in 5G wireless technology, including multiple-input multiple-output (MIMO) systems and full-duplex communications, have opened the gate for Internet of Things (IoT) applications, especially for wireless sensor nodes to collect and transfer data between environment and control center. This study analyzes the deployment of transmit antenna selection (TAS) in spatial modulation (SM) MIMO full-duplex relaying (FDR) system (SM-MIMO-FDR), where relay uses decode-and-forward (DF) protocol. Due to the computational complexity, TAS was usually neglected in previous studies on SM-MIMO system, especially when FDR is employed in the system. Here, we derive the exact form of outage probability (OP) and symbol error rate (SER) to indicate the performance of SM-MIMO-FDR system with TAS over Rayleigh fading channel. A comparison between SM-MIMO-FDR with TAS and conventional SM-MIMO-FDR shows a significant performance enhancement. Also, this study includes the impact of antenna quantity, data transmission rate, and residual self-interference (RSI) on the OP and SER through derived mathematical expressions. Finally, the correctness of the analysis is verified by numerical results through Monte Carlo simulations.

Performance Analysis of Variant MIMO Systems Over 3-D Vehicular to Vehicular Channel

This article analyzes the performance of variant multiple-input multiple-output (MIMO) systems over three-dimensional (3D) vehicular to vehicular (V2V) wireless communication channel. In particular, quadrature spatial modulation (QSM), spatial multiplexing (SMX) and spatial modulation (SM) MIMO techniques are considered. A unified framework to analyze the average bit error rate (BER) for all considered MIMO techniques is developed while considering the 3D geometry dependent stochastic V2V channel model and substantiated through Monte Carlo simulation results. Reported results corroborate the accuracy of the derived formulas and the impact of different system and channel parameters is studied. Specifically, the encroachment of Doppler effect, channel estimation errors, 3D features and vehicle traffic density (VTD) on the BER performance of all systems are examined and discussed. It is revealed that QSM system achieves substantial gains as compared to its counterpart SM and SMX schemes. Gains of up to 2-4 dB in signal-to-noise-ratio are reported for different scenarios.

On the Performance of Full-Duplex Spatial Modulation MIMO System With and Without Transmit Antenna Selection Under Imperfect Hardware Conditions

Hardware impairments (HI) due to imperfect manufactured electronic parts degrade the performance of wireless systems. In this paper, we consider a bidirectional full-duplex (FD) spatial modulation (SM) multiple-input multiple-output (MIMO) system with non-ideal hardware and residual self-interference (RSI). We propose to use the transmission antenna selection (TAS) as a solution to mitigate this degradation. The performance of the considered system is analyzed using mathematical analysis. Specifically, we first derive the exact closed-form expressions of the outage probability (OP), symbol error probability (SEP), and achievable data rate (ADR) for two cases: with and without TAS. Given these expressions, we conduct a detailed evaluation of the system performance under various scenarios to gain insight into its behavior. Essential conclusions are then made on HI and RSI’s impacts, especially for the case with TAS and high transmission rates.

Implementation and analysis of MIMO system based on Alamouti coding

Use of multiple antennas at the receiver and transmitter in a wireless network is a rapidly emerging technology that promises higher data rates at longer ranges without consuming extra bandwidth or transmit power. These systems can be with single-input multiple-output (SIMO), multiple-input single-output (MISO), or with multiple-input multiple-output (MIMO) architectures to improve the signal quality at the receiver using multiple data pipes over a link. MIMO communication system considers multiple antennas used at the transmitting end as well as the receiving end. In addition, the MIMO system has the ability to spread in the spatial domain which is combined in such a way that they either create effective multiple parallel spatial data pipes and diversity to improve the quality (for example decrease the bit error rate). The benefit from the multiple antennas arise from the new dimension space. Hence, the spatial dimension comes as a complement to time. MIMO technology also known as space-time ‘wirelesses’. Space–time block coding (STBC) is a technique used in wireless communications to transmit multiple copies of a data stream across a number of antennas and to exploit the various received versions of the data to improve the reliability of data transfer. The Alamouti coding is a STBC coding technique that is widely use in wireless communication. Alamouti coding can be used in different models like using 2×1 MISO mode or a 2×2 MIMO mode and it can use OFDM system. The purpose of this project is to test a performance of wireless communication system under different type of noise, and the channel model. Also, implementation and analysis of MIMO system based on Alamouti STBC coding.

A Constrained Clustering-Based Blind Detector for Spatial Modulation

In this letter, we propose a novel clustering-based detector for spatial modulation multiple-input multiple-output (MIMO) system. Specifically, we first convert unconstrained optimization problem of conventional K-means algorithm to the constrained optimization by controlling the number of received symbols in each cluster. Then, a low-complexity greedy algorithm is designed for solving the constrained optimization problem to determine the cluster centroids of the proposed detector and a novel detector based on the greedy algorithm is proposed accordingly. Simulation results show that the proposed detector efficiently avoids the occurrence of error floor effects of conventional K-means detector and can achieve near-maximum likelihood (ML) performance even if the number of clusters is large while effectively reducing the complexity compared to existing blind detectors.

Low complexity and high performance EP-SU large-scale MIMO detection based on expectation propagation

In recent years, the detection algorithm based on expectation propagation in high-dimension high-order modulation multiple-input-multiple-output (MIMO) systems shows a huge advantage over the traditional detection algorithm; however, this MIMO-based detection algorithm suffers from the prohibited complexity caused by matrix inversion in each iteration. In this paper, an EP-SU detection algorithm for large-scale MIMO systems is proposed. On the one hand, a successive updating method of information nodes is proposed, which speeds up the efficiency of information updating and avoids the matrix inversion of original EP; on the other hand, the single node update algorithm is optimized, which improves the efficiency and accuracy of information update. Simulation results show that the proposed EP-SU detection algorithm in various large-scale MIMO scenarios exhibits a more outstanding detection performance, faster convergence rate, lower error flat layer, and lower computational complexity compared with traditional EP detection; most importantly, these advantages will be more significant at higher antenna scales.

MIMO Modes in LTE

The multiple input multiple output (MIMO) technology is a key technology for fourth generation (4G) and beyond wireless communications. The MIMO exploits the space diversity to improve performance as well as augment its capacity. Long term evolution (LTE), the dominant 4G standard, operates in diverse MIMO modes, including spatial multiplexing, spatial diversity, and beamforming techniques to combine the advantages of spatial diversity and spatial multiplexing. This article discusses the various modes in LTE and analyses the performance of the single input single output (SISO) and the single input multiple output (SIMO) modes with selection combining (SC) and maximal ratio combining (MRC) at the receiver end. multiplexing (OFDM) is the multiple. The analysis was done on different values of power decay factor and the different number of channel taps. The performance of MIMO configurations for varying power delay profiles and resolvable paths has been analyzed. It is inferred that the higher number of resolvable paths and a low scattering propagating environment augments the performance.

Effect of Wiring and Cabling Topologies on the Performance of Distributed MIMO OFDM VLC Systems

Since most indoor spaces have multiple luminaires for illumination, for visible light communication (VLC) systems, multiple-input multiple-output (MIMO) communication emerges as a natural solution to improve the data rates and/or the link reliability. The existing works on MIMO VLC systems, however, overlook the characteristics of the lighting infrastructure and the luminaire design, which might have implications for the VLC system design. A luminaire typically consists of multiple LED chips. The wiring topology refers to how the LED chips are connected within the luminaire. The cabling topology, on the other hand, refers to how the luminaires are connected to the communication access point (AP). Based on the type and length of cabling and wiring, significant delays can be introduced, which should be taken into account in channel modeling. In this paper, we adopt the non-sequential ray tracing to model the distributed MIMO VLC channels for various practical wiring and cabling topologies. Based on the developed channel models, we provide a comparative performance analysis of repetition coding (RC), spatial multiplexing (SMUX), and spatial modulation (SMOD) MIMO modes. Our results quantify the effect of wiring/cabling delays and provide insights into the optimized design of lighting infrastructure and luminaires for the support of VLC as an add-on service.

Adaptive MIMO FSO Communication Systems with Spatial Mode Switching

In this paper, we propose an adaptive multiple-input multiple-output (MIMO) free-space optical (FSO) system with dynamic adaptation between spatial modes of operation. The proposed adaptive system supports three MIMO modes. In the spatial multiplexing mode, the system transmits independent parallel data streams over multiple apertures to increase data rate. In diversity mode, the system transmits coded streams through multiple apertures to extract diversity gains. In hybrid mode, a trade-off between diversity and multiplexing gains is targeted. For each operation mode, we first derive the outage probability for the MIMO FSO system over log-normal turbulence channels. Then, we formulate the design of an adaptive FSO system to select the MIMO mode that yields the highest throughput while satisfying a predefined target outage probability. Extensive numerical results are provided to demonstrate the performance of the proposed adaptive scheme.