Alamouti Space-time Block Code Research Articles

A Survey on Physical Layer Performance of MIMO-WiMAX

The IEEE 802.16 WiMAX standard for BWA (Broadband Wireless Access) was designed to offer end users high transmission data rates across wider regions.Wireless communication requires MIMO systems because they enable data to be sent and received through multiple antennas. This study examines how the MIMO-WiMAX physical layer performs while using different modulation techniques and channel coding approaches the BER performance of WiMAX systems, the Alamouti Space Time Block Code method for MIMO is being investigated.

Partially decoupled polarization demultiplexing and phase noise equalizer for Alamouti code-based simplified coherent systems.

Alamouti space-time block code (STBC) combined with a simple heterodyne coherent receiver can realize polarization-insensitive phase-diversity detection to reduce the cost. In the receiver, a joint equalizer has been used for STBC's polarization demultiplexing and phase tracking. However, the joint equalizer requires two different step size parameters to update the tap weight coefficients for polarization demultiplexing and the phase noise estimation. This leads to the search process being complex so requiring more iterations for convergence. In this paper, we propose a partially decoupled equalizer that consists of a polarization and phase decoupled equalizer (PPDE) and a pilot-aided blind phase search (P-BPS) algorithm to accelerate the convergence and improve the phase noise tolerance. By theoretically calculating the phase noise, the PPDE can achieve polarization demultiplexing with only one single step size parameter, thus suppressing the searching space and greatly reducing the iterations required for convergence. In the carrier phase recovery stage, the P-BPS algorithm can effectively improve the phase noise tolerance and solve the cyclic slip problem of BPS. We conduct numerical simulations and an experiment to transmit a quadrature phase-shift keying (QPSK) signal. The results demonstrate that the number of iterations required for PPDE convergence is only half of that of the joint equalizer while maintaining polarization-insensitive characteristics in large phase noise. Meanwhile, the achievable linewidth tolerance of P-BPS is increased by three times compared with DD-LMS.

Performance analysis of IRS-assist wireless communication system with Alamouti transmit diversity scheme

Intelligent Reflecting Surface (IRS) is an emerging and growing technology for upcoming B5G and 6G wireless standards to design a perfect smart radio environment. In this article, we try to enhance the physical layer performance of the IRS- assist wireless communication system by taking some helpful performance metrics such as the outage probability (OP), average bit error rate (ABER), and average capacity of the system. Here, we assume our system is mainly affected by phase shift noise and quantization noise due to a discrete number of phase shifts of the IRS elements. The Alamouti STBC transmitter diversity technique is used to design the IRS-assist MISO wireless communication system to mitigate the effect of these kinds of noise, leading to the works’ novelty. We have derived a new and most accurate mathematical framework of PDF and MGF of the corresponding proposed IRS-assist wireless communication system with an end-to-end signal-to-noise ratio (SNR). Behind this statistical distribution, we expressed unique and more precise closed-form expressions of each performance metric under IRS assist SISO and MISO wireless link for the entire SNR region and it is significantly observed that the proposed MISO system provides better outcomes than the general SISO system. Furthermore, we calculate the diversity order of both configurations and it shows that the diversity order of the links is associated with the number of reflecting elements, phase noise error, and average magnitudes of the system. We also validated our analytical outcomes using Monte Carlo simulation results from MATLAB.

On Space-Time Block-Encoded 16-APSK in Aeronautical Mobile Telemetry

The two-antenna problem in aeronautical mobile telemetry is created by the reception of two copies of the same RF waveform with different phases and time delays. Alamouti and Alamouti-like space time block codes can solve the two-antenna problem, but the decoder/detector needs to account for the different time delays between the signals received from the two transmit antennas. This paper compares the performance of Alamouti space-time block codes and time-reversed space-time block codes with 16-APSK to solve the two-antenna problem. The maximum likelihood decoder/detector for Alamouti-encoded 16-APSK is a sequence detector operating on a trellis with a large number of states. A practical state-reduction technique is presented that produces a trellis with 256 states and a small loss in bit error rate performance. The decoder/detector for the time-reversed space time block requires only waveform manipulations and pulse shape matched filtering in the case where the two channels are simple delays. The bit error rate performance of the simplified decoder/detector produces no detectable loss in the bit error rate performance.

Secrecy outage probability and diversity order of Alamouti STBC over time-selective fading channels

Secrecy outage probability and diversity order of Alamouti STBC over time-selective fading channels

Blind block timing estimation for Alamouti STBC: An adaptive cyclostationary-based approach

Block timing synchronization, which could be data-aided or non-data-aided, is a critical part of space–time block codes (STBCs) for recovery of transmitted symbols. The data-aided schemes are not suited for some problems like bandwidth efficiency and most of the existing non-data-aided techniques rely on the received signals statistics and channel coefficients estimation increasing their complexity. In this paper, a non-data-aided cyclostationary-based approach is proposed for block timing estimation in Alamouti STBC employing frequency-shifted versions of the received signals. The method is non-statistical with low complexity and requires no knowledge of channel coefficients. Simulation results confirm the effectiveness of the method.

Outage Analysis of Alamouti-NOMA Scheme for Hybrid Satellite–Terrestrial Relay Networks

In this article, we investigate the performance of hybrid satellite–terrestrial relay networks with multiuser downlink nonorthogonal multiple access. The satellite applies Alamouti space–time block coding, and users exploit a receive antenna selection technique. Communication between the satellite and users is assumed to be established with the aid of a half-duplex terrestrial relay equipped with multiple receive antennas and operating in amplify-and-forward mode, because of the heavy masking effects attributed to environmental obstacles. Subsequently, the satellite–relay link is exposed to shadowed-Rician fading, whereas the relay–users links undergo Nakagami- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$m$ </tex-math></inline-formula> fading, which is a generic statistical channel model for nonterrestrial networks. To be more practical, we consider imperfect successive interference cancellation. The exact outage probability of each user and the corresponding asymptotic expression at the high signal-to-noise ratio are derived to demonstrate the system performance. The analysis indicates that the shadowing conditions do not affect the array gain when the diversity order is dominated by the multiantenna configuration of the second hop. The theoretical derivations are validated by using Monte Carlo simulations. The numerical results indicate that the proposed scheme significantly improves the performance of each user under various shadowing conditions. It also outperforms orthogonal multiple access when proper power levels are allocated to users.

On the Performance of Cache-Free/Cache-Aided STBC-NOMA in Cognitive Hybrid Satellite-Terrestrial Networks

Future wireless networks pose several challenges such as high spectral efficiency, wide coverage, massive connectivity, low receiver complexity, etc. To this end, this letter investigates an overlay-based cognitive hybrid satellite-terrestrial network (CHSTN) combining non-orthogonal multiple access (NOMA) and conventional Alamouti space-time block coding (STBC) techniques. Herein, a decode-and-forward based secondary terrestrial network cooperates with a primary satellite network for dynamic spectrum access. Further, for reliable content delivery and low latency requirements, wireless caching is employed, whereby the secondary network can store the most popular contents of the primary network. Considering the relevant heterogeneous fading channel models and the NOMA-based imperfect successive interference cancellation, we examine the performance of CHSTN for the cache-free (CF) STBC-NOMA and the cache-aided (CA) STBC-NOMA schemes. We assess the outage probability expressions for primary and secondary networks and further, highlight the corresponding achievable diversity orders. Indicatively, the proposed CF/CA STBC-NOMA schemes for CHSTN perform significantly better than the benchmark standalone NOMA and OMA schemes.

UAV-Assisted NOMA-Based Network with Alamouti Space-Time Block Coding

In this study, a 3-user system was considered in the Unmanned Aerial Vehicle-Assisted (UAV-Assisted) Non-Orthogonal Multiple Access-Based (NOMA-Based) communication network. In the network, UAV communicates with users on the ground via two antennas using the Alamouti Space-Time Block Coding (A-STBC) technique. It is considered that there are two separate scenarios where user links are designed with one antenna and two antenna systems. In the study, Monte-Carlo simulations were carried out to understand the effects of using the A-STBC technique in UAV-Assisted NOMA-Based communication networks and increased antenna diversity in receiver and transmitter in the network to the performance of the system. For the benchmark, the downlink NOMA network was used, where the receivers and the UAV are designed with a single antenna. In the simulation results, with the A-STBC technique in the system and increase in diversity, the effects of Path Loss (PL) and environmental factors on error performance were examined. Especially in high Signal to Noise Ratio (SNR) values, it has been observed that the effects of these destructive factors on error performance are highly minimized. Also, the use of A-STBC technique and the increase in diversity in the system provided considerable SNR gain. Moreover, it has been observed that full diversity gain can be achieved when the A-STBC technique is used in the UAV-Assisted downlink NOMA-Based communication system.

STBC-Assisted MDC-NOMA Image Transmission Scheme for Multi-Antenna Systems

As an efficient and interference-resistant coding technique, multiple description coding (MDC) is proposed with the aim to solve the transmission unreliability problem caused by packet errors, loss or blocking delays. The integration of MDC with non-orthogonal multiple access (NOMA) scheme (MDC-NOMA) can effectively boost the robustness and throughput of the underlying system. Additionally, space-time block coding (STBC) can further enhance the system reliability with increased diversity gain, as well as reduced decoding complexity. In this paper, we propose a novel framework referred to as MDC-NOMA-STBC, in which we apply Alamouti STBC integrated with MDC and NOMA to implement more reliable transmission. Specifically, NOMA signals are constructed by superimposing the descriptions from different users, then transmitted by the base station (BS) using Alamouti STBC. In order to substantiate the performance of the proposed framework, first, we derive closed-form expressions of both the outage probability and ergodic rate for each user in a two-antenna BS scenario. Second, for multi-antenna BS, we investigate different antenna selection strategies to further enhance the outage performance under the considered framework, whose analytical expression is provided wherever possible. Third, Monte Carlo simulation results are presented to validate our theoretical framework and to corroborate the superiority of the proposed MDC-NOMA-STBC over state-of-the-art MDC-NOMA scheme. Moreover, under realistic contexts with image transmission, it is confirmed that MDC-NOMA-STBC outperforms its counterpart MDC-NOMA in terms of the peak signal-to-noise ratio and the bit error rate.

On the achievable secrecy transmission rates by Alamouti space‐time block coding in time‐selective fading channels

In this letter, the authors study the security performance of Alamouti space-time block coding (STBC) with two different linear detection strategies, linear maximum likelihood (LML) and zero-forcing (ZF), over time-selective Rayleigh fading channels. Specifically, the connection and secrecy outage probabilities for general temporal correlation when the legitimate receiver and eavesdropper adopt the LML and ZF detectors are first derived. Then the secrecy transmission rates for various combinations of LML and ZF detectors at the legitimate receiver and eavesdropper are derived. The authors also found that the optimal control of the codeword rate and secrecy rate can maximize the secrecy transmission rates.

Low Complexity Deep Learning-Assisted Golden Code Sphere-Decoding with Sorted Detection Subsets

Golden code is a space-time block coding (STBC) scheme that has spatial multiplexing gain over the Alamouti STBC which is widely used in modern wireless communication standards. Golden code has not been widely adopted in modern wireless standards because of its inherent high detection complexity. However, detection algorithms like the sphere-decoding with sorted detection subsets (SD-SDS) have been developed to lower this detection complexity. Literature indicates that the SD-SDS algorithm has lower detection complexity relative to the traditional sphere-decoding (SD) algorithm, for all signal-to-noise ratio (SNR) values. The SD-SDS algorithm exhibits low detection complexity at high SNR; however, at low SNR the detection complexity is higher. We propose a deep neural network (DNN) aided SD-SDS algorithm (SD-SDS-DNN) that will lower the Golden code's SD-SDS low SNR detection complexity, whilst maintaining the bit-error-rate (BER) performance. The proposed SD-SDS-DNN is shown to achieve a 75% reduction in detection complexity relative to SD-SDS at low SNR values for 16-QAM, whilst maintaining the BER performance. For 64-QAM, the SD-SDS-DNN achieves 99% reduction in detection complexity relative to the SD-SDS at low SNR, whilst maintaining the BER performance. The SD-SDS-DNN has also shown to achieve low detection complexity comparable to that of the Alamouti linear maximum likelihood (ML) detector for a spectral efficiency of 8 bits/s/Hz. For a spectral efficiency of 12 bits/s/Hz, the SD-SDS-DNN achieves a detection complexity that is 90% lower than the Alamouti linear ML detector.

A performance study of a genetic algorithm based mapper design for uncoded space‐time labeling diversity

AbstractThe extent to which uncoded space‐time labeling diversity (USTLD) achieves labeling diversity (LD) depends on the binary mappers used to encode information codewords. Current mapper design algorithms are constrained to constellations of modulation order due to the high computational costs involved. To reduce the computational costs, a genetic algorithm (GA) implementation had been proposed to design LD mappers irrespective of constellation shape or size. Current literature based on designing LD mappers using the GA has not been exhaustively tested for high‐density constellations. This article applies the high‐density mappers to the GA that will produce matching or improved LD mapper designs. Additionally, the GA is analyzed and compared to existing algorithmic approaches that produce LD mappers. The GA had produced high‐density M‐QAM mapper designs that match but did not improve upon existing heuristic and algorithmic mapper designs. In the case of high‐density M‐PSK constellations, the 64‐PSK, 128‐PSK, and 256‐PSK constellations exhibited diversity gains of approximately 5, 4, and 8 dB over existing heuristic mapper designs while exhibiting gains of approximately 9, 7, and 10 dB over the Alamouti STBC at the BER of , respectively. The 128‐APSK and 256‐APSK mappers produced by the GA exhibited diversity gains of approximately 3 and 6 dB over existing mapper designs and approximately 7 and 12 dB over the Alamouti STBC at the BER of . The GA produced LD mapper designs for asymmetric 32‐APSK, 64‐APSK, 128‐APSK, and 256‐APSK constellations. These constellations exhibited diversity gains of approximately 5, 17, 5, and 5 dB over the Alamouti STBC, respectively. The GA was found to produce mapper designs that match or improve upon existing heuristic and algorithmic approaches. A computational complexity analysis was performed on the GA, to which the GA was found to have a complexity of . This was exponentially less expensive than exhaustive search and branch‐and‐bound QAP solvers.

Analytical performance evaluation of a 2 × 2 Alamouti STBC OFDM FSO- communication system over turbulent atmospheric channel

An expository methodology is introduced to assess the CNR and BER performance of a STBC OFDM FSO framework over turbulent channel. Expressions are developed for conditional CNR and BER for a given turbulence induced fading. Average BER is then found considering the pdf of turbulence induced fading of gamma-gamma distribution. Results are evaluated for 2 × 2 Alamouti STBC OFDM FSO communication system over turbulent atmospheric channel for several values of system parameters viz. number of OFDM subcarriers, turbulence variance, link distance, data rate and power penalty suffered by the system due to atmospheric turbulence. The results show that the BER performance is strongly degraded due to the effect of atmospheric turbulence. Systems suffers significant amount of power penalty in receiver sensitivity at a given BER. However, the power penalty can be reduced by increasing the number of OFDM subcarriers. For example, power penalty at a BER of10−9 for 2 × 2 STBC with N = 16 OFDM subcarriers is found to be 5.5 dB and the power penalty reduces to 0.35 dB when N is increased to 64.

A New Transmit Diversity Technique for FSK Exploiting its Orthogonality

We propose a new transmit diversity technique for frequency shift keying (FSK). The main idea behind our proposed scheme is to exploit the orthogonality between FSK carriers in order to render signals transmitted from different antennas orthogonal at the receiver, which results in full diversity. Since the proposed scheme achieves antenna orthogonality within one time unit while the well-known Alamouti space-time block code (STBC) needs two time units, it succeeds to be more robust against time-selectivity of the channels than the STBC without deteriorating peak-to-average power ratio (PAPR) of the signal. Simulation demonstrates that the proposed scheme has an error floor that is ten times lower than the STBC over time-selective channels.

Transmit diversity and performance analysis for aeronautical broadband satellite communication systems

This paper analyzes the downlink transmission performance of an aeronautical broadband satellite communication system operating at millimeter wave (mmWave) band. Specifically, by considering that two adjacent satellites cooperatively communicate with an airplane employing an antenna array, we first propose a simple transmit scheme combining Alamouti space time block coding (STBC) with receive beamforming (BF) to improve the system performance. Then, by considering the phase shift errors in phased array antenna deployed at the airplane, we analyze the equivalent output signal-to-noise ratio (SNR) of the considered communication system. Further, with the help of the moment generating function (MGF) approach, we derive the average symbol error rate (ASER) of the system with the proposed transmit scheme, where the satellite links undergo correlated shadow-Rician (SR) fading. Finally, computer simulations are conducted to confirm the validity of the theoretical analysis and reveal the effect of phase errors on the performance of the aeronautical broadband communication system.

STBC-assisted OFDM with Subcarrier Power Modulation

In this work, OFDM-SPM technique is compounded with Alamouti space-time block coding (STBC) in a multiple-input-single-output (MISO) setup to study, investigate and quantify the wireless system’s performance of their combination over a wireless multipath Rayleigh fading channel.

Millimeter-Wave Channel Modeling in a Vehicular Ad-Hoc Network Using Bose–Chaudhuri–Hocquenghem (BCH) Code

The increase in capacity demand for vehicular communication is generating interest among researchers. The standard spectra allocated to VANET tend to be saturated and are no longer enough for real-time applications. Millimeter-wave is a potential candidate for VANET applications. However, millimeter-wave is susceptible to pathloss and fading, which degrade system performance. Beamforming, multi-input multi-output (MIMO) and diversity techniques are being employed to minimize throughput, reliability and data rate issues. This paper presents a tractable channel model for VANET in which system performance degradation due to error is addressed by concatenated Alamouti space-time block coding (ASTBC) and Bose–Chaudhuri–Hocquenghem (BCH) coding. Two closed-form approximations of bit error rate (BER), one for BCH in Rayleigh fading and the second for BCH with ASTBC, are derived. These expressions comprise SNR and code rate and can be utilized in designing VANET architectures. The results show that the BER using concatenated ASTBC and BCH outmatches the conventional BER ASTBC expression. The analytical results are compared with numerical results, thereby showing the accuracy of our closed-form expressions. The performance of the proposed expressions is evaluated using different code rates.

A Janus compatible software-defined underwater acoustic multiple-input multiple-output modem

This article describes the implementation of a multiple-input multiple-output acoustic communication link in shallow water conditions to enable a software-defined acoustic modem with a maximum transmission rate of 20 kbps in a 5-kHz bandwidth. The reliability improvement of a low-complexity Alamouti space–time block code is evaluated to improve the diversity in a high-rate transmission mode using single carrier modulation, as well as in a low-rate transmission mode relying on continuous-phase frequency-shift keying. Using measurements in realistic subsea conditions, the effect of the spatial channel correlation is demonstrated. It is found that for the space–time block code/continuous-phase frequency-shift keying, the spatial diversity is significantly degraded due to the high spatial correlation. In contrast, for the high-mode transmission rate, space–time block code with single carrier modulation offers a bit error rate improvement by a factor over hundred, in comparison to a single transmit element, demonstrating that the multiple-input multiple-output optimal code depends on the software-defined acoustic modem transmission mode.

Performance Analysis of Short-Packet Non-Orthogonal Multiple Access With Alamouti Space-Time Block Coding

This paper presents the analytical performance analysis for short-packet non-orthogonal multiple access (NOMA) systems with the Alamouti space-time block coding (STBC) scheme over Nakagami- $m$ fading channels. In the considered system, the base station (BS) with two antennas transmits short packets to two users with single antenna simultaneously by using Alamouti STBC, assuming that statistical and instantaneous channel state information (CSI) is known at the BS and the two users, respectively. The exact closed-from expressions are derived for the average block error rate (BLER) at each user. Then the simple expressions are derived for the asymptotic average BLER at high signal-to-noise ratios (SNRs). We further derive the optimal power allocation coefficients and the minimum blocklength to satisfy the average BLERs at two users. Finally, Monte Carlo simulations are used to verify the theoretical results and numerical results demonstrate the performance advantage of the STBC-NOMA scheme over the counterpart STBC-OMA one in terms of achieving low-latency transmission.