Intelligent reflecting surface (IRS) can realize information manipulation and signal modulations to perform space-timecoding wireless communication. This article introduces a novel model to perform space-timeblock c...
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Intelligent reflecting surface (IRS) can realize information manipulation and signal modulations to perform space-timecoding wireless communication. This article introduces a novel model to perform space-time block coding (STBC), where the base station transmits multiple symbols to a destination through multiple IRS that are utilized to adjust the phase shift and establish strong links. To maximize the end-to-end SNR, we propose a graph theory based method to obtain the optimal transmit antenna selection (TAS) scheme. Based the optimal TAS scheme, we derive the statistical characterizations of the sum of independent generalized gamma random variables to obtain end-to-end signal-to-noise ratio expressions. Then, the closed-form expressions of outage probability (OP) and symbol error rate (SER) are formulated respectively to evaluate the coverage and reliability performance in wireless communication systems. Furthermore, the asymptotic expressions for OP and SER at a high transmission power are given, then the diversity order is discussed to observe the performance limit. To verify this theoretical performance analysis, extensive computer simulations are conducted to prove its effectiveness. The simulation results show that the multi-IRS-aided STBC system can attain the same or even better performance as the STBC system based on multiple amplify-and-forward relays using a little number of reflecting elements. More interestingly, the OP and SER of this system decrease more than that of the relays-aided system as transmission power increases.
The intelligent reflecting surface (IRS) serves to manipulate information and modulate signals, facilitating space-timecoding in wireless communication. This study presents an innovative model for implementing space-...
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ISBN:
(纸本)9798350303582;9798350303599
The intelligent reflecting surface (IRS) serves to manipulate information and modulate signals, facilitating space-timecoding in wireless communication. This study presents an innovative model for implementing space-time block coding (STBC), where the base station transmits multiple symbols to a user using multiple IRSs. These IRSs manipulate phase shifts to establish robust links. Initially, statistical characterizations are derived for the sum of independent generalized gamma (GG) random variables, providing expressions for the end-to-end signal-to-noise ratio (SNR). Subsequently, a closed-form expression for symbol error rate (SER) is developed to evaluate reliability performance. Additionally, an asymptotic expression for SER at high transmission power is supplied to outline performance limits. Simulation results reveal that the STBC system assisted by multiple IRSs attains comparable or superior performance when contrasted with the STBC system that employs multiple amplify-and-forward (AF) relays, utilizing a restricted number of reflecting units.
In this letter, the beam squint problem, which causes significant variations in radiated beam gain over frequencies in a millimeter wave communication system, is investigated. A constant modulus beamformer design, whi...
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In this letter, the beam squint problem, which causes significant variations in radiated beam gain over frequencies in a millimeter wave communication system, is investigated. A constant modulus beamformer design, which is formulated to maximize the expected average beam gain within the bandwidth with limited variation over frequencies within the bandwidth, is proposed. A semidefinite relaxation method is developed to solve the optimization problem under the constant modulus constraints. Depending on the eigenvalues of the optimal solution, either direct beamforming or transmit diversity-based beamforming is employed for data transmissions. Through numerical results, the proposed transmission scheme can compensate for beam squint effectively and improve system throughput. Overall, a transmission scheme for beam squint compensation in wide-band wireless communication systems is provided.
Purpose A recent innovative technology used in wireless communication is recognized as multiple input multiple output (MIMO) communication system and became popular for quicker data transmission speed. This technology...
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Purpose A recent innovative technology used in wireless communication is recognized as multiple input multiple output (MIMO) communication system and became popular for quicker data transmission speed. This technology is being examined and implemented for the latest broadband wireless connectivity networks. Though high-capacity wireless channel is identified, there is still requirement of better techniques to get increased data transmission speed with acceptable reliability. There are two types of systems comprising of multi-antennas placed at transmitting and receiving sides, of which first is diversity technique and another is spatial multiplexing method. By making use of these diversity techniques, the reliability of transmitting signal can be improved. The fundamental method of the diversity is to transform wireless channel such as Rayleigh fading into steady additive white Gaussian noise (AWGN) channel which is devoid of any disastrous fading of the signal. The maximum transmission speed that can be achieved by spatial multiplexing methods is nearly equal to channel capacity of MIMO. Conversely, for diversity methods, the maximum speed of broadcasting is much lower than channel capacity of MIMO. With the advent of space-time block coding (STBC) antenna diversity technique, higher-speed data transmission is achievable for spatially multiplexed multiple input multiple output (SM-MIMO) system. At the receiving end, detection of the signal is a complex task for system which exhibits SM-MIMO. Additionally, a link modification method is implemented to decide appropriate coding and modulation scheme such as space diversity technique STBC to use two-way radio resources efficiently. The proposed work attempts to improve detection of signal at receiving end by employing STBC diversity technique for linear detection methods such as zero forcing (ZF), minimum mean square error (MMSE), ordered successive interference cancellation (OSIC) and maximum likelihood detection (MLD
As global demand for high-speed telecommunications and Internet of Things (IoT) services continues to rise exponentially, the limitations of the crowded radio frequency (RF) spectrum are becoming more apparent. With b...
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As global demand for high-speed telecommunications and Internet of Things (IoT) services continues to rise exponentially, the limitations of the crowded radio frequency (RF) spectrum are becoming more apparent. With bandwidth scarcity leading to increased latency, interference, and data bottlenecks, alternative solutions are urgently needed. Visible Light Communication (VLC) is gaining momentum as a next-generation wireless technology capable of alleviating these constraints. Operating within the visible spectrum, VLC provides an unlicensed, high-bandwidth alternative that offers significant advantages in terms of data rate, availability, reliability, and physical-layer security. This work proposes a novel wireless optical communication system specifically designed for outdoor use. The system incorporates forward error correction (FEC) through space-time block coding (STBC) to enhance resilience against signal degradation, noise, and environmental interference. A comprehensive simulation was conducted to evaluate system performance under varying weather conditions, including dry, rainy, and foggy scenarios. The proposed system demonstrated successful data transmission rates of 15 Gbps across a 100-meter link using four white LEDs as the light sources. Bit error rate (BER) was maintained at 10(-)(3), with corresponding signal-to-noise ratio (SNR) values of 21 dB in dry weather, 22 dB in rain, and 23 dB in fog. These results indicate strong performance and robustness across diverse environmental conditions, outperforming previous VLC configurations. This study not only underscores the viability of VLC as a high-speed, secure alternative to RF-based communication but also lays the groundwork for future development. Upcoming efforts will focus on hardware prototyping, real-world testing, and adaptive algorithms to further enhance system reliability.
To enhance the performance in practical communications, a novel construction of polar code is designed for a rational polar and space-time block coding (Polar-STBC) system. The Polar-STBC system can be equivalent to a...
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ISBN:
(纸本)9781509017010
To enhance the performance in practical communications, a novel construction of polar code is designed for a rational polar and space-time block coding (Polar-STBC) system. The Polar-STBC system can be equivalent to a single transmission channel for each polar code bit in Rayleigh fading MIMO channels, and the equivalent channel can be regarded as a fading channel, of which the gain coefficient and additive noise are studied. Moreover, the distribution of the additive noise is also derived. Finally, we show that the bit error rate performance of our Polar-STBC system in 2 x 2, 4 x 2 and 4 x 4 MIMOs.
We propose a linear precoder for the layered space-time block coding system [2] over spatially correlated channels with channel covariance matrix feedback at the transmitter. The precoder is a combination of the well ...
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ISBN:
(纸本)9781467372183
We propose a linear precoder for the layered space-time block coding system [2] over spatially correlated channels with channel covariance matrix feedback at the transmitter. The precoder is a combination of the well known waterfilling solution and the precoder for spatial multiplexing system that minimizes the probability of decoding error. At the receiver, decoding schemes of group zero-forcing and group minimum mean squared error with successive interference cancellation are utilized to decode the transmitted signals. Simulation results demonstrate the superiority of the combined linear precoder over the pure waterfilling solution or the spatial multiplexing precoder in correlated channel. This conclusion confirms the intuition that the optimal linear precoding should be robust to both the space-time block coding and spatial multiplexing systems.
The capacity enhancement for random coherent optical multiple-input multiple-output (MIMO) channels in multi-mode fiber (MMF) links is investigated theoretically. Additionally, the performance of space-timeblock codi...
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The capacity enhancement for random coherent optical multiple-input multiple-output (MIMO) channels in multi-mode fiber (MMF) links is investigated theoretically. Additionally, the performance of space-time block coding (STBC) techniques for achieving high reliability optical MIMO transmission is numerically examined. A comparative study is performed by considering several schemes that employ multiple transmitters/receivers. Simulation results of these schemes, in terms of bit error rate (BER) as a function of optical signal to noise ratio (OSNR), are provided. (C) 2012 Elsevier GmbH. All rights reserved.
Based on imperfect channel state information with channel estimation error at the receiver and delayed feedback at the transmitter, a suboptimal power allocation (PA) scheme to minimize bit error rate (BER) under a po...
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Based on imperfect channel state information with channel estimation error at the receiver and delayed feedback at the transmitter, a suboptimal power allocation (PA) scheme to minimize bit error rate (BER) under a power constraint is developed for beamforming multi-antenna systems with space-time block coding. The proposed scheme is based on a so-called compressed signal-to-noise ratio criterion, where a single compressed factor is utilized, and it can be used to generalize some existing schemes by setting the compressed factor to different forms. A closed-form compressed factor is derived to minimize the BER, and the resultant close-form expression of power allocation is attained. This closed-form expression is computational efficient and can obtain the BER performance close to the existing optimal approach which requires numerical search. Simulation results show that the proposed scheme can provide BER lower than the equal power allocation scheme. However, due to the impact of both estimation error and delayed feedback, it has performance degradation when compared to the PA scheme with estimation error or delayed feedback only. (C) 2012 Elsevier GmbH. All rights reserved.
space-timeblock coded differential spatial modulation (STBC-DSM) is a recently proposed DSM-based multiple-input-multiple-output (MIMO) transmission technique with high diversity gain. The existing low-complexity det...
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space-timeblock coded differential spatial modulation (STBC-DSM) is a recently proposed DSM-based multiple-input-multiple-output (MIMO) transmission technique with high diversity gain. The existing low-complexity detectors for STBC-DSM can be further designed to reduce complexity. In this paper, we propose an ordered antenna index vector detector (OVD) for STBC-DSM, and an OV-low repetition detector (OV-LRD) for further simplification. The OVD detects the symbols in a designed order, and the OV-LRD fully uses the STBC structure to simplify the OVD. Simulation results show that the OVD achieves near-optimal performance, and the OV-LRD significantly reduces complexity with negligible performance loss.
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