Antenna Selection Scheme Research Articles

Transmit Antenna Selection in Offset Spatial Modulation Systems

In this letter, the idea of transmit antenna selection is combined with the offset spatial modulation (OSM) technique. Specifically, two novel transmit antenna selection schemes, termed as antenna selection based on grouped Euclidean distance (AS-GED) and channel coefficient (AS-CC), are developed toward a flexible tradeoff between system performance and computational complexity. Simulation results show that the proposed antenna selection schemes achieve significant performance improvement compared to traditional OSM systems.

On Secure Mixed RF-FSO Systems With TAS and Imperfect CSI

In this work, we analyze the secrecy outage performance of a dual-hop relay system composed of multiple-input-multiple-output radio-frequency (RF) links and a free-space optical (FSO) link while a multiple-antenna eavesdropper wiretaps the confidential information by decoding the received signals from the resource node. The channel state information (CSI) of the RF and FSO links is considered to be outdated. We propose three transmit antenna selection (TAS) schemes to enhance the secrecy performance of the considered systems. The secrecy outage performance with different TAS schemes is analyzed and the effects of misalignment and detection technology on the secrecy outage performance of mixed systems are studied. We derive the closed-form expressions for probability density function (PDF) and cumulative distribution function (CDF) over M\'alaga channel with imperfect CSI. Then the closed-form expressions for the CDF and PDF of the equivalent signal-to-noise ratio (SNR) at the legitimate receiver over Nakagami-$m$ and M\'alaga channels are derived. Furthermore, the lower bound of the secrecy outage probability (SOP) with different TAS schemes are derived. Besides, the asymptotic results for SOP are investigated by exploiting the unfolding of Meijer's $G$-function when the electrical SNR of FSO link approaches infinity. Finally, Monte-Carlo simulation results are presented to testify the correctness of the proposed analysis. The results illustrate that the outdated CSI shows a strong effect on the secrecy outage performance. In addition, increasing the number of antennas at the source cannot significantly enhance the secrecy performance of the considered systems.

Efficient transmit antenna selection and resource allocation scheme for mmWave D2D networks

Employing switchable directional antennas in the user equipment (UE) is becoming a popular method to replace conventional beamforming methods. This approach is mainly applicable to mmWave networks due to the small size of directional microstrip antenna elements on corresponding frequencies, and requires exploiting proper transmit antenna selection (TAS) schemes to obtain the optimal directivity of selected active antennas. TAS is rather complex in the heterogeneous cellular networks with underlaid D2D communication. For each D2D user, selecting transmit antennas with maximum radiation gain does not necessarily lead to the optimal throughput due to the potential interference that might be imposed on other high priority users, thus, finding the optimal transmit antennas of users is generally a challenging issue in networks with multi-antenna D2D users. In this work, based on Lagrangian relaxation method, we propose a novel and efficient transmit antenna selection and resource (channel and power) allocation (ASRA) for D2D mmWave networks. In order to validate the performance of our proposed algorithm, we devise another efficient low-complexity greedy-based ASRA as well. Numerical results verify the performance of our proposed Lagrangian-based ASRA in comparison to other methods.

Transmit Antenna Selection Strategies for SC- FDMA- IDMA Massive MIMO Systems

The 5 G wireless offers many advancements over the prevalent 4 G LTE communication networks, such as enhanced data transmission rates (in order of Gbps), Substantially reduced latency, many times increase in the Base Station Capacity and praiseworthy betterments in the QoS offered to the users. IDMA has already proven its potential in 5 G and it can be easily integrated in to massive MIMO systems. The ideology behind the concept of Massive MIMO is to match the requirement for efficient usage of spectrum, and is implemented using several numbers of antennas at the Base Station, catering to a number of subscribers concurrently using same band of the given frequency. However, the cost and complexity of implementation of such large-scale antenna systems is quite high. Thus for reduction in the number of radio frequency chains, the technique of Transmit Antenna Selection is used. In this paper, we propose two transmit antenna selection strategies considered for individual user or overall users based on selection criteria maximum sum rate or minimum bit error performance considering for (MIMO) multiuser multiple input and multiple output single carrier frequency division multiple access based interleave division multiple access wireless system (MIMO-SCFDMA-IDMA). We have taken this scheme for the uplink communication and selection of the subcarrier is through the bulk selection. The performance may get degraded in case of heavy load of multiple subcarriers attached to one antenna, which will in turn call for the role of power amplifier and thus efficiency of the system may go down. Therefore, here we prefer bulk subcarrier selection instead of per subcarrier selection. It is shown in this paper that enhanced sum rate can be achieved as more users are allowed to transmit concurrently, and thus multiuser gain is achieved. We also demonstrated the comparison with simulation result of sum rate performance and Bit error rate performance of varying users. Result shows that antenna selection based on overall system is better than the antenna selection considering each user.

Joint transmit antenna selection and precoding for millimeter wave massive MIMO systems

Millimeter wave (mmW) communication coupled with massive MIMO architecture is attaining considerable attention to overcome the huge data rate requirements. Increasing the dimensions of a massive MIMO architecture provides spatial multiplexing gains, but at the cost of decrease in hardware efficiency. To optimize the energy efficiency of massive MIMO systems, in this paper, focusing on a sub-connected hybrid architecture, we propose a joint transmit antenna selection and precoding technique. Low Complexity heuristic algorithms are used to perform the antenna selection in order to limit the number of active antennas, hence, decreasing the power consumption which subsequently increases the energy efficiency. Precoding for the selected transmit antennas is performed using successive interference cancellation (SIC) based scheme. Simulation results show that the heuristic algorithms based transmit antenna selection scheme requires less computations and its performance is close to exhaustive search algorithm. Furthermore, SIC based precoding enables to overcome serious signal attenuation of mmW systems and performs best in terms of spectral efficiency for a partially connected hybrid structure. The joint solution is optimal in-terms of computational complexity and energy efficiency, which optimizes the performance of mmW massive MIMO systems.

Analysis of secrecy outage performance of TAS–CIOD systems over wireless Rayleigh fading channels

In this paper, the physical layer (PHY) security performance for a coordinate interleaved orthogonal design (CIOD) for space–time coding system with transmit antenna selection scheme (TAS) is analyzed and evaluated. As an important performance measure for the PHY security in the wireless systems, closed-form expression is derived for the secrecy outage probability (SOP) of a CIOD space–time coding system, where transmit antennas selection is employed. Using the numerical results obtained from the derived closed-form expression, the SOP performance of the CIOD with TAS is presented and compared with that of the classical orthogonal space–time block coding (OSTBC) system, in which Alamouti coding and transmit antenna selection scheme is employed. We show that the CIOD with transmit antenna selection can provide a superior secrecy performance than the Alamouti-OSTBC system with TAS. To verify the analysis we also provide the Monte Carlo simulation results to show the accuracy of the results obtained from theoretical expressions derived in this paper.

Antenna selection strategy for transmit beamforming-based joint radar-communication system

Antenna array-based joint radar-communication (JRC) system employs the beamforming strategy to steer the transmit signals in different directions such that different beamforming weight vectors are exploited which perform the corresponding radar-communication objectives. Such functionality has been provisioned in the spectrally congested environments where both systems are destined to coexist. The transmit antenna selection has become an increasingly interesting topic as the antennas become significantly cheaper and smaller relative to the up-conversion chains. In this paper, we address the problem of antenna selection for the JRC system by employing a re-weighted l1-norm minimization naturally yielding the low-complexity solution compared to the exhaustive l0-norm-based optimization. We present the mathematical framework for the proposed approach in the context of the individual as well as grouped beamforming weight vectors and analyze the practical applicability of the proposed approach for both cases. We argue that the grouped approach for optimizing the JRC antenna selection is hardware-efficient compared to the antenna selection for individual beamforming weight vectors. Simulation results illustrate that the proposed technique significantly reduces the number of required antennas while simultaneously satisfying the radar and communication system objectives.

Transceiver Design and Signal Detection in Backscatter Communication Systems With Multiple-Antenna Tags

Ambient backscatter technology utilizes ambient radio frequency (RF) signals to enable battery-free devices (tags and readers) to communicate. Most existing studies assume single-antenna tags. However, in this paper, we consider tags with multiple antennas, which are exploited to provide transmit diversity. Channel state information (CSI) estimation is then a fundamental challenge because the tags can transmit few or no training symbols. To overcome it, we require detectors that operate without CSI. Thus, we propose and design three detectors based on the chi-squared test, F-test and Bartlett's test. The latter two are blind detectors because they require neither CSI nor the knowledge of RF source power and noise variance. We derive the detection probability bounds for the first two detectors. We also propose optimal tag antenna selection schemes to maximize the detection probabilities. Finally, simulation results are provided to corroborate our theoretical studies.

A Novel Machine Learning Aided Antenna Selection Scheme for MIMO Internet of Things.

In this article, we propose a multi-label convolution neural network (MLCNN)-aided transmit antenna selection (AS) scheme for end-to-end multiple-input multiple-output (MIMO) Internet of Things (IoT) communication systems in correlated channel conditions. In contrast to the conventional single-label multi-class classification ML schemes, we opt for using the concept of multi-label in the proposed MLCNN-aided transmit AS MIMO IoT system, which may greatly reduce the length of training labels in the case of multi-antenna selection. Additionally, applying multi-label concept may significantly improve the prediction accuracy of the trained MLCNN model under correlated large-scale MIMO channel conditions with less training data. The corresponding simulation results verified that the proposed MLCNN-aided AS scheme may be capable of achieving near-optimal capacity performance in real time, and the performance is relatively insensitive to the effects of imperfect CSI.

Efficient Selection on Spatial Modulation Antennas: Learning or Boosting

In this letter, a novel deep learning-based transmit antenna selection (TAS) scheme for the multiple-input multiple-output (MIMO) with spatial modulation (SM) system is proposed. We formulate the generalized TAS pipeline in both neural networks (NN) and gradient boosting decision trees (GBDT), in which the importance of different features reflecting the different elements from channel state information (CSI) is analyzed regarding to the empirical data as well. Furthermore, the bit error rate (BER) performance and the complexity comparison of two structures is investigated. Simulation results confirm that GBDT can be efficiently implemented for real-time application with near-optimal performance.

Secure transmission using optimal antenna selection for MIMO underlay CRN with multiple primary users

The authors present a method of utilisation diversity combining to improve the secrecy performance of an underlay cognitive radio network (CRN) with single or multiple primary users (PUs) over Rayleigh fading environment. They consider a practical scenario where a secondary transmitter $({ST_X})$ ( S T X ) , a secondary receiver $({SR_X})$ ( S R X ) , and an eavesdropper (Eve) receiver are equipped with multiple antennas while all PUs are employed with a single antenna. The confidential information is transmitted from ${ST_X}$ S T X to ${SR_X}$ S R X under the malicious attempt of an Eve. Generalised selection combining is applied at the ${SR_X}$ S R X , and maximal ratio combining is adopted at the Eve. Depending upon the availability of the global channel state information of the main and eavesdropper's channels at ${ST_X}$ S T X , the secrecy outage performances of optimal antenna selection and sub-optimal antenna selection schemes have been examined. They derive a closed-form expression for the exact secrecy outage probability, asymptotic secrecy outage probability and intercept probability in a Rayleigh fading environment. Numerical results show that secrecy performance of the network improves with increasing the transmitting antennas while it degrades with increasing the number of PUs.

RETRACTED ARTICLE: Antenna selection with improved group based particle swarm optimization (IGPSO) and joint adaptive beam forming for wideband millimeter wave communication

In general, realization of large array communication for mm Wave systems is non-vital. Radio Traditional digital antenna array that comprises of one Radio Frequency (RF) chain for every antenna leads to high consumption of energy, complexity in signal processing, residue of noise. However, one major drawback of analogue beam forming lies in its inability to support spatial multiplexing. Minimum Variance Distortion less Response (MVDR) is enhanced to rectify this noise inference and also the variance/power of interference. The major aim of this work is to maximize the MVDR and minimum Signal-To-Interference-Plus-Noise Ratio (SINR through effective designing of beamforming and optimal selection of antenna. Antenna selection based on power is proposed at first step and beamforming vector is optimized after selection of antenna as like in single-user setup. In case of impossibility of separation of multi-path signal, performance is enhanced by an Improved Group based Particle Swarm Optimization (IGPSO) based antenna selection and Joint adaptive beamforming scheme is proposed. A Beamforming coefficient of the entire user’s associated with an antenna is assigned to zero by MVDR and SINR in order to deactivate certain antenna. So, IGPSO is deployed in design of beamforming and joint selection of antenna. It has a non-convex constraint. Convex constraint is used for effectively approximate it. Experimental results shows that proposed design including array of lens antenna is able to produce better performance than benchmark schemes with reduced Bit Error Rate (BER) and improved spectral efficiently in terms of Spectrum efficiency and max min rate.

Sparse array design for multiple switched beams using iterative antenna selection method

Digital beamforming (DBF) arrays with a large number of small antennas are extensively employed in millimeter-wave (mmWave) sensing systems. Sparse arrays have been posed as an attractive solution to mmWave systems due to their capability of striking the best compromise between performance and complexity. We propose two iterative antenna selection strategies, referred to as deterministic selection and adaptive selection, to design sparse DBF arrays in this paper. The first strategy assumes a common sparse array associated with different beamforming weights for multiple switched beams, while the other exploits switching networks to adaptively change the sparse array configuration with different beams. To counteract hardware-related issues that arise in practical realizations, we then propose guided adaptive selection and regularized adaptive selection to impose additional constraints for different switching networks. The optimality of sparse DBF arrays is defined in terms of both transmit and receive patterns. Taking that into account, an iterative re-weighted l1-norm is modified to promote boolean sparsity of the selection vector in this work. Simulation results validate the effectiveness of proposed antenna selection methods.

Performance Analysis and Optimization for Power Beacon-Assisted Wireless Powered Cooperative NOMA Systems

Wireless power transfer (WPT) is an effective way to prolong the lifetime of the energy-constraint networks. In this paper, we investigate a wireless powered cooperative non-orthogonal multiple access (WP-CNOMA) system, consisting of a power beacon (PB), an information transmitter (S), multiple relays (R) and two information receiving devices with near device <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$D_{1}$ </tex-math></inline-formula> and far device <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$D_{2}$ </tex-math></inline-formula> . We assume both S and R are energy-constraint and there is no direct link between S and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$D_{2}$ </tex-math></inline-formula> . With the help of PB, S and R can harvest energy from it to restart the communication for WP-CNOMA network. For such a system, low-complexity but effective relay and antenna selection schemes are applied. To characterize the performance, outage probabilities and average throughput are derived for linear and non-linear energy harvesting (EH) models, respectively. Moreover, to maximize the average throughput, invoking the unimodal feature for average throughput with respect to the EH time, we find the optimal EH time via Golden section search method. Simulation results validate the accuracy of analytical results, and reveal the performance gain for our system over the benchmark schemes. Also, it can be seen that the non-linear EH model shows different outage behaviors from the linear one. On the other hand, considering the practical application and to improve the performance, the optimization for a simple WP-CNOMA system with single-antenna PB and single relay is also investigated, in which we aim to maximize the minimum throughput by jointly optimizing EH time and power allocation. A low-complexity analytical method is developed to find the max-min rate. Numerical results show that through optimization, the system performance can be improved significantly.

Multiuser Space–Time Line Code With Transmit Antenna Selection

In this paper, a multiuser space-time line code (MU-STLC) scheme is newly designed that concurrently delivers multiple STLC signals to multiple users, and a preprocessing matrix for the MU-STLC is derived based on the minimum mean square error criterion. The novel MU-STLC method retains the conventional STLC receiver structure so that each user linearly combines the received signals without using the full channel state information to decode the STLC signals. With more transmit antennas than the number of users having two receive antennas, a transmit antenna selection (TAS) scheme is investigated in combination with the proposed MU-STLC method, and the detection signal-to-interferenceplus-noise ratio (SINR) is derived depending on a specific TAS pattern. The performance improvement obtained from the TAS is significant, yet finding the optimal TAS pattern is a combinatorial problem that requires prohibitively high computational complexity. To resolve this issue, a greedy TAS algorithm is also proposed that iteratively selects the transmit antenna maximizing the detection SINR in each greedy step. The numerical results verify the efficacy of the proposed MU-STLC system with the SINR-based greedy TAS algorithm in terms of the bit error rate performance and computational complexity. For example, comparing with a scheme that selects four antennas from eight antennas randomly to support four users, the proposed TAS scheme can reduce the required signal-to-noise ratio for achieving 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> bit-error-rate by approximately 6 dB when quadrature phase-shift keying is employed. Furthermore, the proposed method can achieve comparable performance to the optimal antenna selection scheme with the reduced computational complexity by O(M <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> ) from O(M <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">U+3</sup> ), where M and U are the numbers of transmit antennas and selected antennas (or users), respectively.

Transmit Antenna Selection for Space–Time Line Code Systems

In this study, we consider a space-time line code (STLC) system with N transmit antennas and two receive antennas. Although the STLC system is scalable to an arbitrary number of transmit antennas, a large number of them will increase the hardware cost and complicate the implementation of the system. To resolve this practical limitation, we propose a transmit antenna selection (TAS) scheme for the N-by-2 STLC system. If S ≤ N antennas are used for the transmission, the STLC transmitter selects the S antennas such that the instantaneous signal-to-noise ratio (SNR) is maximized. For a comprehensive performance analysis, the instantaneous SNR of the proposed TAS is characterized in terms of the statistical mean and moment-generating function (MGF). To investigate the performance of the proposed TAS approach, the approximated expression of error rate is derived based on the MGF method. Moreover, using asymptotic analysis, we show that the proposed TAS-STLC system achieves full spatial diversity of 2N, while the coding gain is affected by N, S, and the modulation order. As a special case, we also provide a mathematical analysis of the error rate of the conventional STLC system when N = S.

Optimized Antenna Selection and Adaptive Power Allocation for Physical Layer Network Coding with Selective Soft-Message-Forward Cooperation

To improve the systematic bit error rate (BER) performance and power efficiency, an optimized antenna selection and adaptive power allocation scheme is proposed for physical layer network coding (PNC) with selective soft-message-forward (SSMF) cooperation. In this scheme, two adaptive power allocation (APA) schemes are proposed for the multiple access (MA) and broadcast (BC) stages, respectively. In the MA stage, the APA scheme aims to maximize the Euclidean distance of network coding symbols received by relay node. In the second BC stage, the relay node takes the maximization of the minimum mutual information of two source nodes as objective function. Then it uses the narrow range method (NRM) to select the optimal antenna set and equally allocates power to them. To further reduce the systematic complexity, an antenna set pre-selection is proposed. It minimizes the antenna number in the initial antenna set of the NRM based on the deletion standard which does not reduce the mutual information in the BC stage. Simulation results indicate that our APA schemes surpass the existing equal power allocation (EPA) scheme with a binary phase-shift keying modulation. Compared with current EPA scheme, the proposed APA schemes for the BC, MA and global stages obtain about 1 dB, 2 dB and 3.5 dB performance gains at BER of 10−3 with two antennas in the relay node, respectively.

Improving the Performance of Spatial Modulation Full-Duplex Relaying System With Hardware Impairment Using Transmit Antenna Selection

This paper aims to study the impact of hardware impairments (HI) on the performance of spatial modulation (SM) system with full-duplex relay (FDR), namely SM-FDR system. To combat the negative effect of HI, a transmit antenna selection (TAS) scheme is applied at transmitter. The system performance in terms of outage probability (OP) and symbol error rate (SER) in case of HI and ideal hardware are compared. Furthermore, the impact of TAS on the system performance is also considered. This study derives successfully the exact expression of the OP and the approximate expression of the SER with TAS under the impact of both HI and residual self-interference (RSI). Both HI and RSI have strong influence on the performance of the SM-FDR system, especially at high data transmission rate, and the influence of the former is higher. However, the system performance is significantly enhanced, i.e. the SER is reduced, when TAS is applied. Therefore, it is recommended to apply TAS to improve the performance of SM-FDR systems when both HI and RSI exist in reality. Finally, all analytical expressions are validated by Monte Carlo simulation.

Performance Analysis and Antenna Selection for Space Time Line Code

In this article, we investigate the recently developed space time line code (STLC) scheme, which utilizes the channel state information (CSI) for encoding at the transmiter to achieve full spatial diversity gain. The theoretical analysis of the bit error rate (BER) performance for STLC is first evaluated. Moreover, aiming at alleviating the cost of radio frequency (RF) chains, antenna selection at both the transmitter and receiver sides is developed by minimizing the derived instantaneous BER. Furthermore, in the context of a flat Rayleigh fading channel, we derive an upper bound for quantifying the BER performance of STLC with both transmit and receive antenna selection. Finally, simulation results validate the accuracy of the above theoretical analysis results and show the performance improvement of the developed antenna selection schemes.

On ASER Analysis of Energy Efficient Modulation Schemes for a Device-to-Device MIMO Relay Network

In this paper, we investigate the performance of a device-to-device (D2D) multiple-input and multiple-output (MIMO) communications using an amplify-and-forward relaying for various energy-efficient modulation schemes. For analysis, transmit antenna selection strategy is employed at the transmitter to select the best transmit antenna which maximizes the received signal power. In the analysis, we optimized the relay location to obtain the lowest outage probability possible and derived the generalized upper-bound average symbol error rate expressions of energy-efficient futuristic modulation schemes such as square quadrature amplitude modulation (QAM), rectangular QAM, cross QAM, and hexagonal QAM for D2D network. Further, we have derived the ergodic capacity expression to calculate the achievable rates. Comparative analysis of different QAM schemes for various constellation orders is also presented. Furthermore, the impact of the relative position of relay, path loss, and the number of antennas are also highlighted. Finally, the derived analytical results are verified through Monte-Carlo simulations.