Transmit Antenna Selection Technique Research Articles

Deep Learning-Assisted Transmit Antenna Classifiers for Fully Generalized Spatial Modulation: Online Efficiency Replaces Offline Complexity

In this work, deep learning (DL)-based transmit antenna selection (TAS) strategies are employed to enhance the average bit error rate (ABER) and energy efficiency (EE) performance of a spectrally efficient fully generalized spatial modulation (FGSM) scheme. The Euclidean distance-based antenna selection (EDAS), a frequently employed TAS technique, has a high search complexity but offers optimal ABER performance. To address TAS with minimal complexity, we present DL-based approaches that reframe the traditional TAS problem as a classification learning problem. To reduce the energy consumption and latency of the system, we presented three DL architectures in this study, namely a feed-forward neural network (FNN), a recurrent neural network (RNN), and a 1D convolutional neural network (CNN). The proposed system can efficiently process and make predictions based on the new data with minimal latency, as DL-based modeling is a one-time procedure. In addition, the performance of the proposed DL strategies is compared to two other popular machine learning methods: support vector machine (SVM) and K-nearest neighbor (KNN). While comparing DL architectures with SVM on the same dataset, it is seen that the proposed FNN architecture offers a ~3.15% accuracy boost. The proposed FNN architecture achieves an improved signal-to-noise ratio (SNR) gain of ~2.2 dB over FGSM without TAS (FGSM-WTAS). All proposed DL techniques outperform FGSM-WTAS.

NOMA with optimal transmit antenna selection scheme with self adaptive metaheuristic model

AbstractNonorthogonal multiple access (NOMA) constitutes a promising technique in the fifth‐generation (5G) mobile networks. On the transmitter side, the concurrent usage of multiple antennas needs an appropriate count of parallel Radio Frequency (RF) chains at the front end. Owing to this consequence, it maximizes the power consumption, cost, and system complexity along with maximization in the antenna count. In order to tackle these aforesaid problems, some researchers prefer the Transmit Antenna Selection (TAS) for modeling the transmitter structure simple. The best antenna is selected opportunistically by an efficient TAS technique from multiple antennas and deploys a single RF chain for transmission. In this paper, a novel approach for optimized antenna selection in overlay CR networks using NOMA and SM is proposed via the usage of optimization tactics. To choose the desired respective antenna, this paper introduces a new Mean and Median Fitness Centered Moth flame Optimization (MM‐FCMO), which is the modified Moth Flame Optimization (MFO) Algorithm, which taken the core objectives such as power consumption and Mean Square Error (MSE). The MSE and power consumption of the chosen antennas have to be lower for the system to attain maximum antenna gain with lower noise. Finally, to exhibit that the presented work is much significant than the traditional works, a comparative analysis is made in terms of error minimization and statistical evaluation.

Performance of Transmit Antenna Selection in Multiple Input Multiple Output-Orthogonal Space Time Block Code (MIMO-OSTBC) System Joint with Bose-Chaudhuri-Hocquenghem (BCH)-Turbo Code (TC) in Rayleigh Fading Channel

The Transmit antenna selection (TAS) technique is essential to increase the efficiency of spatial modulation (SM) systems. This TAS is an effective technique for reducing the Multiple Input Multiple Output (MIMO) systems, which can increase the computational difficulty and Bit error rate (BER) by various TAS algorithms. But these selection methods cannot provide code gain, so it is essential to join the external code in TAS to obtain code gain advantages in BER. In some existing work, the improved BER has been perceived by joining Forward Error Correction Code (FEC) and Space Time Block Code (STBC) for MIMO systems provided greater code gain. A multiple TAS-OSTBC technique with new integration of Bose–Chaudhuri–Hocquenghem (BCH)-Turbo code (TC) is proposed in this paper. The TAS-OSTBC system connects with the external BCH code in sequence of internal Turbo code. This combination can provide increasing code gain and the effective advantages of the TAS-OSTBC system. To perform the system analysis Rayleigh channel is utilized. In the case with multiple TAS-OSTBC systems, better performance can provide by this new combination of the BCH-Turbo compared to the conventional Turbo code for the Rayleigh fading.

Transmit Antenna Selection Methods For Mimo Systems In Wireless Communications

Though MIMO systems improve performance of a wireless communication network by the usage of multiple antennas, demand of distinct set of RF chain (i.e., electronic components required for antenna transmission and reception, in wireless communication) for all the antennas leads to an increase in complexity and cost. Antenna selection technique of MIMO has proved to be a good means to solve this issue. Antenna Selection methods find optimal number of antennas required out of the total antennas present in the MIMO (Multiple Input Multiple Output) system. The selection of antenna can be performed at both ends of the communication network i.e., transmitter or receiver. In this paper, an overview of various Transmit Antenna Selection techniques for various MIMO systems is presented.

On the performance of energy harvesting AF partial relay selection with TAS and outdated channel state information over identical channels

Energy scarcity has been known to be one of the most noticeable challenges in wireless communication system. In this paper, the performance of an energy harvesting based partial relay selection (PRS) cooperative system with transmit antenna selection (TAS) and outdated channel state information (CSI) is investigated. The system dual-hops links are assumed to follow Rayleigh distribution and the relay selection is based on outdated CSI of the first link. To realize the benefit of multiple antenna, the amplified-and-forward (AF) relay nodes then employs the TAS technique for signal transmission and signal reception is achieved at the destination through maximum ratio combining (MRC) scheme. Thus, the closed-form expression for the system equivalent end-to-end cumulative distribution function (CDF) is derived. Based on this, the analytical closed-form expressions for the outage probability, average bit error rate, and throughput for the delay-limited transmission mode are then obtained. The results illustrated that the energy harvesting time, relay distance, channel correlation coefficient, the number of relay transmit antennas and destination received antenna have significant effect on the system performance. Monte-carol simulation is employed to validate the accuracy of the derived expressions.

A detailed review on non-orthogonal multiple accessbased spatial modulation systems

PurposeNon-orthogonal multiple access (NOMA) is a much hopeful scheme, which is deployed to enhance the spectral efficiency (SE) significantly, and it also enhances the massive access that has attained substantial concern from industrial and academic domains. However, the deployment of superposition coding (SC) at the receiver side resulted in interference. For reducing this interference, “multi-antenna NOMA” seems to be an emerging solution. Particularly, by using the channel state information at the transmitter, spatial beam forming could be deployed that eliminates the interference in an effective manner.Design/methodology/approachThis survey analyzes the literature review and diverse techniques regarding the NOMA-based spatial modulation (SM) environment. It reviews a bunch of research papers and states a significant analysis. Initially, the analysis depicts various transmit antenna selection techniques that are contributed in different papers. This survey offers a comprehensive study regarding the chronological review and performance achievements in each contribution. The analytical review also concerns on the amplitude phase modulation (APM) selection schemes adopted in several contributions. Moreover, the objective functions adopted in the reviewed works are also analyzed. Finally, the survey extends with various research issues and its gaps that can be useful for the researchers to promote improved future works on NOMA-based SM.FindingsThis paper contributes to a review related to NOMA-based SM systems. Various techniques and performance measures adopted in each paper are analyzed and described in this survey. More particularly, the selection of transmission antenna and APM are also examined in this review work. Moreover, the defined objective function of each paper is also observed and made a chronological review as well. Finally, the research challenges along with the gaps on NOMA-based SM systems are also elaborated.Originality/valueThis paper presents a brief analysis of NOMA-based SM systems. To the best of the authors’ knowledge, this is the first work that uses NOMA-based SM systems to enhance SE.

General performance of detect-and-forward cooperative relaying in the presence of multiple interferers for optimum combining receivers

Detect-and-Forward (DF) is a cooperative technique based on the retransmission of a detected version of the transmit signal. It improves performance, throughput and cellular coverage. However, in cellular scenarios, it coexists with co-channel interference (CCI), which is the principal factor that affects the performance of cellular networks. On the other hand, Optimum Combining (OC) is a low complexity combining technique that maximizes the signal-to-interference-plus-noise ratio (SINR), achieving in this case diversity gain by eliminating the CCI. In the present paper, the performance of cooperative DF network in the presence of multiple CCI at relay and destination is analysed, where relay and destination are equipped with multiple antennas and OC. Furthermore, scenarios by considering multiple antenna transmission (MAT) and transmit antenna selection (TAS) technique at relay are supposed. For both MAT and TAS techniques, a tight approximation of the end-to-end instantaneous SINR is proposed. Subsequently, its moment-generating function is derived in closed-form in order to evaluate the average bit-error rate of the system. Analytical results are validated using Monte-Carlo simulations for several scenarios, showing that OC eliminates fully the CCI, even in the case of high-power CCI. The diversity gain depends on the number of destination antennas, relay antennas and interferers.

Multiple TAS-OSTBC in MIMO with Outer BCH Concatenation under Nakagami-m Fading

Transmit Antenna Selection (TAS) technique with Orthogonal Space Time Block Code (OSTBC) addresses the problem of hardware complexity in multiple antenna systems and improves Bit Error Rate (BER) significantly by using various antenna selection algorithms. TAS technique is not able to provide the coding gain. To achieve the coding gain benefits with improvement in BER, it is necessary to concatenate TAS system with an outer code. In literature, it is observed that the concatenation of Forward Error Correction (FEC) codes and Space Time Block Code (STBC) for MIMO systems provides the high coding gain with improved BER. In this paper, a multiple TAS-OSTBC system is proposed with concatenation of channel coding techniques such as BCH and TURBO. The proposed system is concatenated with BCH as outer code in series with TURBO as inner code. This combination provides the capacity benefits of TAS-OSTBC system with improved coding gain. The channel is assumed to be faded by Nakagami- m fading. It is observed that for multiple TAS-OSTBC system this new concatenation of BCH-TURBO code gives improvement of 5 dB at 10-6 as compared to concatenation of TURBO code at m =0.5 for Nakagami- m fading parameter.

Energy‐efficient relay deployment in cellular systems using fractional frequency reuse and transmit antenna selection techniques

SummaryTo cope with the steep surge in mobile traffic, network operators are now expanding their infrastructure for mobile access networks. However, since energy costs and greenhouse gas emissions are a large burden to network operators, they are making great efforts to improve the energy efficiency (EE) of their networks by promising techniques, including relaying and multiple‐input multiple‐output (MIMO). Relaying technique can considerably improve the EE when the interference between base stations (BSs) and relay stations (RSs) is effectively coordinated by an elaborate relay deployment using the fractional frequency reuse (FFR) technique. Also, MIMO techniques improve the radio channel quality through diversity gains, so the system capacity and the EE can be improved. Therefore, a combination of relaying/MIMO techniques can be considered to achieve the higher performance, particularly, if the system complexity and costs of using such techniques are low. Since the transmit antenna selection (TAS), one of MIMO techniques, can provide a sufficient transmit diversity gain and satisfy the requirements for low complexity and cost (thus, practical), the TAS is recommended for use with the relaying technique. In this paper, for an energy‐efficient relay deployment using FFR and TAS techniques, we derive the EE and the resource partitioning according to RS positions and the number of BS antennas by a mathematical analysis. Then, the optimal RS positions according to the number of antennas can be determined by an optimization approach. The numerical and simulation results indicate that the proposed analysis method can efficiently analyze the EE and locate the RSs.

Transmit Antenna Selection Schemes for Quadrature Spatial Modulation

The objective of this paper is to investigate the application of transmit antenna selection (TAS) to quadrature spatial modulation (QSM). The application of optimal Euclidean distance based antenna selection (EDAS) to QSM (EDAS-QSM) is first proposed. EDAS-QSM requires an exhaustive search, which imposes a significantly high computational complexity. In this regard, a reduced-complexity algorithm for the computation of EDAS-QSM is proposed. Finally, several low-complexity, sub-optimal TAS techniques for QSM are investigated. The decision metrics of these schemes are based on channel amplitude, antenna correlation, Euclidean distance or a combination thereof. Monte Carlo simulation results demonstrate the effectiveness of the proposed schemes, while the computational complexity of each is analysed. The trade-off between error performance and computational complexity is discussed for each of the schemes.

Improving performance of the asynchronous cooperative relay networks with maximum ratio combining and transmit antenna selection technique

In this paper, a new amplify and forward (AF) asynchronous cooperative relay networks using maximum ratio combining (MRC) and transmit antenna selection (TAS) technique is considered. In order to obtain a maximal received diversity gain, the received signal vectors of all antennas of the each relay node are jointly combined by MRC technique in the first phase. Then, only one the selected antenna of each relay will amplify and retransmit the resulting MRC signal vectors to the destination node in the second transmission step of network. The proposed scheme not only offers to reduce the interference components induced by inter-symbol interference (ISI) among the relay nodes, but also can effectively remove them with employment near-optimum detection (NOD) at the destination node as compared with the previous distributed close loop extended-orthogonal space time block code (DCL EO-STBC) scheme. The analysis and simulation results confirm that the new scheme outperforms the previous cooperative relay networks in both synchronous and asynchronous conditions. Moreover, the proposed scheme allows to reduce the requirement of the Radio-Frequency (RF) chains at the relay nodes and is extended to general multi-antenna relay network without decreasing transmission rate.

Low Complexity Capacity Maximizing Transmit Antenna Selection Schemes for Massive MIMO Wireless Communications

Recently massive MIMO systems have attracted a lot of attention. A serious limitation in implementing massive MIMO is the number of RF chains required, which is due to its high implementation cost and power consumption. Antenna selection is a wise remedy, that not only reduces the number of required RF chains, but also improves the system’s performance. In this work, two low complexity capacity-maximizing transmit antenna selection (TAS) schemes, one for low SNR region and one for medium to high SNR region, are proposed. It is shown that the proposed antenna selection schemes enhance the MIMO link’s capacity at low SNRs, and select only one antenna in more than $$90\%$$ of channel realizations, which in terms of numbers of required RF chains is very promising. The performance of the proposed schemes are compared to an existing high performance greedy TAS technique in terms of average capacity and complexity. Finally, a close analytical approximation for average capacity of the proposed capacity-based subset selection scheme is presented.

Joint effect of jamming and noise on the secrecy outage performance of wiretap channels with feedback delay and multiple antennas

AbstractIn this paper, we investigate the secrecy performance of multiple‐input–multiple‐output wiretap channels with outdated channel state information (CSI) at the transmitter. The joint effect of multiple jamming signals and noise at the eavesdropper is studied assuming that the transmitter adopts a transmit antenna selection technique, while both the legitimate receiver and the eavesdropper use a maximal‐ratio combining scheme to achieve spatial diversity in reception. Exact closed‐form expressions for the nonzero secrecy rate probability and the secrecy outage probability for an arbitrary number of power distributed jamming signals are derived, by assuming both perfect and imperfect CSI. The general secrecy outage probability expressions are simplified for 2 special cases, ie, different and equal power distributed interferers. Furthermore, we conduct an asymptotic secrecy outage analysis at high signal‐to‐noise ratio, which reveals that the expected diversity gain cannot be realized for imperfect CSI and full diversity order can only be achieved under the perfect CSI condition. In addition, our results reveal that the number of antennas at the eavesdropper as well as the number of jamming signals do not affect the system diversity order. Simulation results are performed to illustrate the effects of imperfect feedback and other key system parameters on the secrecy performance. Finally, our analytical results are validated through Monte Carlo simulations.

Performance of Enhanced Massive Multiuser MIMO Systems Using Transmit Beamforming and Transmit Antenna Selection Techniques

In this paper, the performances of massive multiuser multiple input multiple output (MMU MIMO) system with different transmit beamforming (BF) techniques and different suboptimal transmit antenna selection (TAS) algorithms over Rayleigh fading channels are investigated. Three linear transmit BF types are considered, namely, maximum ratio transmission (MRT BF), zero forcing (ZF BF) and minimum mean square error (MMSE BF). Two TAS algorithms are considered, that are pairwise error probability minimization (PM) and the capacity maximization (CM). TAS techniques are used in order to reduce the number of radio frequency (RF) chains, system complexity, and cost. This makes MMU MIMO more applicable in beyond 4G communication systems. The simulation results show that TAS algorithms are capable of decreasing the complexity of the system while maintaining the same performance of the MMU MIMO system, complex TAS techniques are not needed at large number of RF chains, and the performance improvement due to the increase of this number is limited to a certain threshold. It also demonstrated that the MMSE BF and ZF BF bit error rate performance values are better than MRT BF values for both CM and PM TAS algorithms, but it is limited to the large number of users. On the other hand, the MRT BF technique performance is good at small Eb/N0 values for both PM and CM TAS but it is relatively less affected by increasing the number of users.

Transmit Antenna Selection with Optimum Combining for Aggregate Interference in Cognitive Underlay Radio Network

Transmit antenna selection (TAS) is most popular technique in underlay cognitive radio (CR) networks as they increase the capacity of secondary users with less hardware requirements. In this paper, a new scenario of CR ad-hoc network topology is proposed in which apart from primary users, there are multiple number of secondary users which are assumed to be distributed as homogeneous spatial Poisson point process (PPP) and are trying to use the primary spectrum in underlay mode. These multiple secondary transmitters generate the aggregate interference and can degrade the performance of secondary receiver. Here this aggregate interference is estimated and its impact on performance of secondary receiver under unconstrained mode of operation is presented. Further, to enhance the performance of secondary receivers in this scenario, single TAS technique based on maximizing the received signal to interference noise ratio by using optimum combining (OC) method is proposed. Furthermore, in this work the design of end to end Simulink based environment for secondary trans---receiver system with advancements in channel design and estimation is proposed. The bit error rate (BER) analysis is presented and verified for image data for single TAS-OC technique for unconstrained mode in underlay CR network in Rician fading channel. The BER performance is also presented for different number of secondary interference sources which are located at fixed distance in one case and they are assumed to be distributed as PPP in another case.

Unified analysis of transmit, receive and hybrid diversity techniques over generalized‐K channels

AbstractIn this work, unified performance analysis of various transmit, receive and hybrid diversity techniques are studied over generalised‐K composite fading channels. Of transmit diversity techniques, orthogonal space‐time block coding, maximal‐ratio transmission and transmit antenna selection techniques are investigated. On the other hand, maximal‐ratio combining and selection combining are examined as receive antenna diversity techniques. In this paper, 10 different multi‐antenna techniques have been analyzed. Exact outage probability, symbol error probability, moment generating function, moments and ergodic capacity expressions are derived in closed‐form. Asymptotic expressions are also derived in order to provide deeper insight by obtaining array and diversity gains of the studied multi‐antenna scenarios. Simulations verify theoretical results. We show that the diversity orders of the investigated scenarios are the minimum of the diversity orders of the system for only small‐scale fading channel case and the shadowing parameter, and limited by the shadowing effect especially in heavy shadowing case. Copyright © 2015 John Wiley & Sons, Ltd.

Unified Performance Analysis of Multi-antenna Techniques in Dual Hop Networks over Nakagami-m Fading Channels

In this paper, various multi-antenna dual hop relay networks are studied over flat Nakagami-m fading channels. The studied scenarios include transmit diversity techniques such as orthogonal space-time block coding, maximal-ratio transmission, and transmit antenna selection techniques and receive diversity techniques such as selection combining and maximal-ratio combining, and hybrid versions of these transmit and receive diversity techniques. In order to study and analyze the performance of the multi-antenna relay networks, closed-form and exact expressions for the moment generating function, the signal-to-noise ratio moments, the outage probability, and the symbol error probability are derived. Besides, to provide further insight about the performance of the studied scenarios asymptotic expressions revealing the array and diversity gain are also derived. Theoretical results are approved by the Monte Carlo simulations.

Performance Analysis of Transmit Antenna Selection with MRC in MIMO for Image Transmission in Multipath Fading Channels Using Simulink

<em><span>Multiple antenna configurations can be used to increase the data throughput reducing the effects of multipath fading and interference when channel bandwidth is limited. Orthogonal Space Time Block Codes along with Transmit antenna selection can improve the performance of multiple input multiple output systems. In this paper, we present the Transmit Antenna Selection (TAS) technique based on the Maximal Ratio Combining (MRC) scheme with single antenna selection for image transmission. The performance analysis of the system was carried out under different fading channels i.e. Rayleigh and Rician channel for image input. We design end to end TAS/MRC system in Simulink with advancements in the channel designs and receive diversity techniques along with the feedback models. The Bit Error Rate (BER) analysis was performed for the combinations of number of transmit and receive antennas for TAS/MRC system for various fading environments.</span></em>

Multiple Transmit Antenna Selection in MIMO-OSTBC System in Nakagami-m Fading Channel

Abstract Transmit Antenna Selection (TAS) is essential part of future wireless systems to reduce the complexity of multiple antenna techniques and to satisfy the need of higher data rates. In this paper, we present TAS technique based on Maximal Ratio Combining (MRC) scheme with multiple antenna selection. The sub optimal antenna selection is carried out for selecting more than one subset of antenna which minimizes the upper bound of pair wise error probability. The performance analysis of the system is carried out under Nakagami-m flat fading channel. The Bit Error Rate (BER) analysis is performed for multiple antenna selection in MIMO-OSTBC system for arbitrary values of ‘m’ in Nakagami-m fading channel.

Further Complexity Reduction Using Rotational Symmetry for EDAS in Spatial Modulation

Euclidean distance antenna selection (EDAS) is an effective transmit antenna selection technique for spatial modulation (SM). However, since an exhaustive search over both the antenna set and the set of conventional constellation points is executed, the computational complexity required to find the optimal solution of EDAS is too high for practical applications. In general, digital modulation constellations have rotational symmetry. In this letter, it is shown that the symmetric constellation points have the same value as EDAS. Hence, only one search is enough for the symmetrical constellation set. Using this proposition, we propose a fast algorithm to find the optimal EDAS solution, which exhibits lower computational complexity than the conventional EDAS solution.