Spatial Modulation MIMO Research Articles

Low-Complex AI-Empowered Receiver for Spatial Media-Based Modulation MIMO Systems

Low-Complex AI-Empowered Receiver for Spatial Media-Based Modulation MIMO Systems

Design of Dynamic Offset Spatial Modulation MIMO for Low-Cost Consumer Electronics Devices

Design of Dynamic Offset Spatial Modulation MIMO for Low-Cost Consumer Electronics Devices

Information-Guided Antenna Selection and Activation for Spatial Modulation MIMO Systems

Information-Guided Antenna Selection and Activation for Spatial Modulation MIMO Systems

Data Transmission and Reception in Spatial Modulation MIMO Wireless Systems and Analysis in Nakagami-m Fading Channels

Data Transmission and Reception in Spatial Modulation MIMO Wireless Systems and Analysis in Nakagami-m Fading Channels

Ergodic Rate Analysis of Massive Spatial Modulation MIMO System With NOMA in Cooperative Relay Networks

In this article, by introducing nonorthogonal multiple access (NOMA) scheme into the massive spatial modulation (SM) MIMO in cooperative relay networks, a massive cooperative NOMA-aided SM (NOMA-SM) system is presented. The ergodic rate performance of uplink massive cooperative NOMA-SM with finite alphabet inputs is investigated over Rayleigh fading channels. According to the performance analysis, the mutual information between the SM signals transmitted by users and the signal received at the base station (BS) is derived. Based on this, the theoretical lower bound and tight approximation of the ergodic rates are deduced for performance evaluation. With the aforementioned results, simple expressions of the ergodic rates are derived for the system with single-antenna relay, which can simplify the calculation of theoretical ergodic rate. Besides, when the number of receive antennas at the BS is very large, the asymptotic ergodic rate analysis is presented for massive cooperative NOMA-SM system, and the corresponding asymptotic lower bounds of the ergodic rate are derived. Simulation results indicate that the presented theoretical analysis is valid and can match the corresponding simulation well. Thus, the ergodic rate performance can be well assessed in theory.

Detection of Spatially Modulated Signals via RLS: Theoretical Bounds and Applications

This paper characterizes the performance of massive multiuser spatial modulation MIMO systems, when a regularized form of the least-squares method is used for detection. For a generic distortion function and right unitarily invariant channel matrices, the per-antenna transmit rate and the asymptotic distortion achieved by this class of detectors are derived. Invoking an asymptotic characterization, we address two particular applications. Namely, we derive the error rate achieved by the computationally-intractable optimal Bayesian detector, and we propose an efficient approach to tune LASSO-type detectors. We further validate our derivations through various numerical experiments.

Expectation Propagation Aided Signal Detection for Uplink Massive Generalized Spatial Modulation MIMO Systems

In this paper, we propose a joint signal detection algorithm under the framework of the expectation propagation (EP) algorithm for uplink massive multiuser multiple-input multiple-output (MIMO) systems with generalized spatial modulation (GSM). By projecting the discrete probability distribution into a multivariate complex Gaussian function, the symbol beliefs of the tridimensional GSM constellation are calculated via the iterative propagation of the mean vectors and covariance matrices. To reduce the computational complexity, an efficient separate signal detection called two-stage EP (TS-EP) algorithm is designed. In the first stage, the active transmit antenna indices are determined via the EP. Each vector-valued variable node (VN) in the factor graph is decomposed into multiple sub-VNs, and the invalid sub-VNs of the determined silent transmit antennas are pruned from the factor graph. In the second stage, since the modulation symbols are independent conditioned on the active transmit antennas, the symbols are independently detected by adopting the EP with univariate complex Gaussian approximations, and the number of probability calculations for each symbol belief is significantly reduced in the subsequent EP update. Simulation results illustrate that the proposed EP and TS-EP signal detection schemes outperform the recently proposed counterparts. Moreover, the proposed TS-EP algorithm strikes a desirable and flexible performance-complexity tradeoff.

Parallel signal detection for generalized spatial modulation MIMO systems

Generalized Spatial Modulation is a recently developed technique that is designed to enhance the efficiency of transmissions in MIMO Systems. However, the procedure for correctly retrieving the sent signal at the receiving end is quite demanding. Specifically, the computation of the maximum likelihood solution is computationally very expensive. In this paper, we propose a parallel method for the computation of the maximum likelihood solution using the parallel computing library OpenMP. The proposed parallel algorithm computes the maximum likelihood solution faster than the sequential version, and substantially reduces the worst-case computing times.

Capacity analysis of cooperative amplify and forward–quadrature spatial modulation MIMO system

Capacity analysis of cooperative amplify and forward–quadrature spatial modulation MIMO system

Performance analysis of AGSM adaptive unipolar MIMO-OFDM for visible light communication

Visible light communication is a leading technology in wireless communication which provides free spectrum with high data rate. In this paper, improvement of the data rate is achieved in the adaptive transmission for U-OFDM system which works on switching of various MIMO modes. In VLC system different MIMO modes give different performance on the basis of their modulation size. The adaptive system switches between spatial modulation (SM), spatial multiplexing (SMUX), repetition code (RC) and adaptive generalized spatial modulation (AGSM) MIMO modes on the basis of received SNR and target Bit Error rate to attain high spectral efficiency (χ). The performance of adaptive generalized spatial modulation mode is analysed and compared with the three modes (RC, SM, SMUX) over 2×2, 4×4, 8×8 MIMO systems in realistic channel models. The simulation results show that significant improvement in data rate and spectral efficiency is achieved using AGSM MIMO mode in comparison to SM, RC and SMUX MIMO modes.

Performance Analysis of Uplink Massive Multiuser SM-MIMO System With Imperfect Channel State Information

In this paper, the error performance and spectrum efficiency (SE) of uplink massive multiuser spatial modulation (SM) MIMO systems with zero-forcing detection for perfect and imperfect channel state information (CSI) are investigated over composite Rayleigh fading channels. We firstly derive the error probabilities of transmit antenna index detection and transmitted symbol detection of each user. Using these results, the bit error rate (BER) performance of the system under perfect CSI is analyzed. Furthermore, a closed-form average BER of the system is derived. We generalize the analytical results of perfect CSI to those of imperfect CSI for practicality, and derive a closed-form BER for the system with imperfect CSI. Based on this, two asymptotic BER expressions are developed to characterize the error performance of the system for large-scale receive antennas and high SNR. By means of the asymptotic expressions, the diversity order of the system is attained. Besides, we derive a lower bound on the achievable SE of the system with imperfect CSI. With this lower bound, an approximate expression of the achievable SE is obtained in closed form. Simulation results indicate that our theoretical analysis is valid, and agrees with simulation results well.

Receivers for the uplink of multiuser generalized spatial modulation MIMO systems

Receivers for the uplink of multiuser generalized spatial modulation MIMO systems

Sparse detection with orthogonal matching pursuit in multiuser uplink quadrature spatial modulation MIMO system

Quadrature spatial modulation (QSM) is one of the most prevalent transmission techniques for future wireless mobile network due to its high spectral efficiency (SE) and low complexity. However, it is restrictive to downlink of the cellular network deployments. Therefore, this paper proposes QSM for the multiuser uplink data transmission that increases the SE of the network by deploying multiple antennas at the mobile user with only two radio frequency (RF) chains. Maximum likelihood (ML) decoder is used to detect the received signal and attains the optimal detection performance but it is impractical because of its high computational complexity. Consequently, this paper proposes compressed sensing (CS) based orthogonal matching pursuit (OMP) detection as it has a suboptimal performance with a low computational complexity which can be a practical solution in the high-density uplink multiuser network. However, conventional OMP algorithm has a low estimation performance due to multiuser interference which corrupt channel matrix. Thus, this work design an equalizer that mitigates the multiuser interference and improve the detection performance by orthonormalizing the columns of channel matrix. Simulation analysis confirm that the proposed QSM technique based on CS detector outperforms the conventional schemes in terms of SE and bit error rate (BER).

Reconfigurable Compact Antenna for Spatial Modulation MIMO Communications

Recently, a new wireless communication scheme called Spatial Modulation MIMO (SM-MIMO) has been introduced for Green wireless communications. Here, an application of a compact reconfigurable antenna working at 2.45 GHz to SM-MIMO is presented. The designed antenna can generate up to eight different radiation patterns. It is composed of two meanderlines radiating elements surrounded by parasitic electronically switchable resonators. The impedance matching has been optimized for six states of the reconfigurable antenna. The spatial diversity, which is a key parameter for SM-MIMO is estimated from the analysis of the complex inter-correlation matrix of the radiation patterns at the operating frequency. Finally, the performance of the designed reconfigurable antenna is assessed by computing the bit error rate (BER) in a Non-Line-of-Sight (NLOS) configuration. The proposed reconfigurable antennas are particularly suitable for indoor SM-MIMO applications that require low power and compact devices.

On the Joint Impact of Hardware and Channel Imperfections on Cognitive Spatial Modulation MIMO Systems: Cramer–Rao Bound Approach

This paper investigates the performance of spatial modulation for multiple-input multiple-output underlay spectrum-sharing systems in the presence of three practical deleterious effects: 1) transceiver hardware impairments, 2) outdated channel state information (CSI), and 3) imperfect CSI. In particular, for Rayleigh fading channels, a closed-form expression of the average pairwise error probability and a tight upper bound of the average bit error rate (ABER) are derived. In addition, asymptotic and yet simple approximate expressions are obtained, and consequently insightful discussions are manifested on the impacts of channel and hardware imperfections and on the diversity order. Moreover, explicit exact and approximate expressions for the Cramer–Rao bound are computed for assessing the channel estimation accuracy. Numerical results, which are validated through simulations, show that nonzero bounds of the ABER occur in the high power domain because of the effects of channel and hardware impairments.

Performance of Multiple Rank Modulation Based on SM-MIMO

Abstract A multiple rank modulation (MRM) scheme is proposed that provides better error performance, enhances the data rate and reduces the system demodulation complexity. Multiple input multiple output (MIMO) scheme is a technique that uses several antennas at the transmitter and receiver to minimize error and optimize data speed. MRM is a novel technique that borrows from spatial modulation-MIMO (SM-MIMO) scheme. The basic idea of this scheme involves the transmitter receiving a group of bits and subdividing them into two blocks; rank index block and signal modulation block. The rank index bit block is used to select the rank to be activated and the rank selected contains at least one active transmit antenna (TA). The signal modulation bit block is encoded in a given modulation scheme for transmission. It is then transmitted through the activated rank that contains at least one active TA. The transmitted encoded signal modulation bit block is received through the receive antenna and a receiver. The receiver estimates a rank index and the transmitted symbol from the signal received. The signal modulation bit block is finally decoded. This paper addresses the performance of MRM scheme based on error performance to run cellular fifth generation (5G). We perform and present simulation results of MIMO systems employing MRM scheme to generate bit error rate (BER) of this system.

Adaptive Spatial Modulation MIMO Based on Machine Learning

In this paper, we propose a novel framework of low-cost link adaptation for spatial modulation multiple-input multiple-output (SM-MIMO) systems-based upon the machine learning paradigm. Specifically, we first convert the problems of transmit antenna selection (TAS) and power allocation (PA) in SM-MIMO to ones-based upon data-driven prediction rather than conventional optimization-driven decisions. Then, supervised-learning classifiers (SLC), such as the K -nearest neighbors (KNN) and support vector machine (SVM) algorithms, are developed to obtain their statistically-consistent solutions. Moreover, for further comparison we integrate deep neural networks (DNN) with these adaptive SM-MIMO schemes, and propose a novel DNN-based multi-label classifier for TAS and PA parameter evaluation. Furthermore, we investigate the design of feature vectors for the SLC and DNN approaches and propose a novel feature vector generator to match the specific transmission mode of SM. As a further advance, our proposed approaches are extended to other adaptive index modulation (IM) schemes, e.g., adaptive modulation (AM) aided orthogonal frequency division multiplexing with IM (OFDM-IM). Our simulation results show that the SLC and DNN-based adaptive SM-MIMO systems outperform many conventional optimization-driven designs and are capable of achieving a near-optimal performance with a significantly lower complexity.

Low-Complexity Detection Algorithms for Spatial Modulation MIMO Systems

In this paper, the authors propose three low-complexity detection schemes for spatial modulation (SM) systems based on the modified beam search (MBS) detection. The MBS detector, which splits the search tree into some subtrees, can reduce the computational complexity by decreasing the nodes retained in each layer. However, the MBS detector does not take into account the effect of subtree search order on computational complexity, and it does not consider the effect of layers search order on the bit-error-rate (BER) performance. The ost-MBS detector starts the search from the subtree where the optimal solution is most likely to be located, which can reduce total searches of nodes in the subsequent subtrees. Thus, it can decrease the computational complexity. When the number of the retained nodes is fixed, which nodes are retained is very important. That is, the different search orders of layers have a direct influence on BER. Based on this, we propose the oy-MBS detector. The ost-oy-MBS detector combines the detection order of ost-MBS and oy-MBS together. The algorithm analysis and experimental results show that the proposed detectors outstrip MBS with respect to the BER performance and the computational complexity.

Efficient Sphere Decoding Based on a Regular Detection Tree for Generalized Spatial Modulation MIMO Systems

Efficient Sphere Decoding Based on a Regular Detection Tree for Generalized Spatial Modulation MIMO Systems

Power Efficient Generalized Spatial Modulation MIMO for Indoor Visible Light Communications

In this letter, we propose an active-space, collaborative constellation-based generalized spatial modulation (GSM) multiple-input multiple-output encoding that can enhance the power efficiency of indoor visible-light communication compared with the conventional optical GSM. Simulation results verify that the proposed scheme can also achieve performance improvement compared with both spatial modulation and conventional GSM under the line-of-sight channel condition, particularly for higher values of spectral efficiency.