Bit Error Rate Performance Research Articles

Investigation of Multiple LED Array Failure on DCO-FBMC Modulation for Indoor Visible Light Communication

Visible light communication (VLC) is a high-speed and power-efficient optical wireless communication method that has gained momentum for data transmission in indoor environments. Indoor VLC systems often use multiple LED arrays to increase the uniformity of brightness and enhance the received energy and the four LED array model is the most commonly used. To suppress the impact of intersymbol interference (ISI) and achieve higher data rates, multicarrier modulation techniques such as orthogonal frequency division multiplexing (OFDM) and filter bank multicarrier (FBMC) have been introduced in VLC systems. The FBMC technique is a promising candidate for the 5G communication system and it has recently been applied to VLC systems. FBMC has several advantages: higher spectrum efficiency, narrower out-of-band radiations and asynchronous transmission. This study investigates the performance of an FBMC-based VLC system when one or more lamps in the multiple LED arrays experience failure. The VLC- FBMC model was implemented using a 4-QAM and 16-QAM format with three various LED array configurations while assuming a line of sight (LOS) model. The LED array model was evaluated based on its ability to achieve good bit error rate (BER) performance, communication quality and high bit rate and meet the required signal-to-noise ratio (SNR). The proposed FBMC model simulation's outcome indicates that the system is still able to transmit data reliably, even in the event of a failure of up to 50% of the lamps. The results indicate that the 2- and 4-lamp models yielded good BER performance, achieving a value of 3.6 × 10−5 and 5.4 × 10−5 respectively. Furthermore, the simulation demonstrated that the optical FBMC-based VLC system attained a high bit rate of 73.2 Mbit/s in the 4-QAM format using the 2-lamp model and a bit rate of 29.3 Mbit/s in 16-QAM format using the 4-lamp model, while maintaining acceptable BER performance.

RIS-assisted differential transmitted spatial modulation design

In this paper, we propose a novel reconfigurable intelligent surface (RIS)-assisted wireless communication design called the RIS-assisted differential transmitted spatial modulation (DTSM) scheme. The encoding process of the differential spatial modulation (DSM) is integrated into the DTSM scheme, where only one transmit antenna is activated per time slot to transmit the M-ary phase shift keying (PSK) modulation symbol through the RIS. Due to the detection characteristics of DSM, the bit error rate (BER) performance remains satisfactory without requiring channel state information estimation, thereby enhancing robustness. The RIS application in the proposed scheme mitigates the effects of shadow area fading by adjusting the phase of the reflected signals to improve the signal-to-noise ratio at the receiver. In simulation results by comparing to other RIS-assisted spatial modulation schemes, we can find that the proposed DTSM scheme demonstrates good BER performance across various scenarios, including Nakagami-m fading, which also indicates its potential for practical applications.

Kalman filtering-based decision threshold dynamic optimization in photonics-aided millimeter-wave systems.

We propose a novel, to the best of our knowledge, decision threshold dynamic optimization (DTDO) method based on Kalman filtering to mitigate the nonlinear effect impacts of the time-domain jitter and saturation distortion on a bit error rate (BER) performance. This dynamic optimization method was validated in a photonics-aided W-band millimeter-wave system. Compared to nonlinear algorithms and clustering classification methods, DTDO offers lower complexity and superior dynamic tracking capabilities when optimizing the BER performance in photonics-aided systems. The four-level pulse amplitude modulation (PAM4) signal, after being transmitted over a 50-m W-band link, was equalized using a low-complexity filter, maintaining an exceptionally low BER. This approach effectively leverages the inherent low-complexity advantages of single-carrier transmission over the link.

Performance Analysis of Reflective Intelligent Surface Assisted Bidirectional Full‐Duplex Communication Systems Over Nakagami‐m$$ m $$ Fading Channels

ABSTRACTIn this paper, a passive reflective intelligent surface (RIS) assisted bidirectional full‐duplex (FD) wireless system in a realistic Nakagami‐ fading with reflective elements and two source nodes is proposed. The source nodes are equipped with dual antennas for FD mode transmission and reception. The primary cause of degradation in the performance of the FD system is self‐interference, which can be reduced by increasing the number of reflective elements on the meta‐surface. Analytical expressions have been derived for the proposed RIS‐aided bidirectional FD wireless systems in terms of outage probability and bit error rate (BER). Numerical results show that doubling the number of reflecting elements considerably improves the outage performance of the proposed system in terms of signal‐to‐noise ratio (SNR) compared with RIS‐assisted half‐duplex (HD) mode. Additionally, different modulation schemes have been employed to evaluate the BER performance of the proposed system. The accuracy of analytical expressions is validated by matching Monte Carlo with analytical simulations.

Real-time modulation classification architecture in software defined radio

Real-time automatic modulation classification (AMC) in software-defined radio (SDR), an emerging approach to blindly detect the modulation scheme in future wireless networks with applications ranging from civilian to military, has not received much attention with practical receiver architecture. This paper proposes a simple modified receiver architecture using reduced Convolutional Neural Networks (CNN) to achieve AMC, which is tested on SDR devices under the bit-error-rate (BER) metric. The results show that the proposed receiver does not change the receiver’s original architecture in practice while achieving good BER performance. The results also show that the proposed low-complexity CNN model can fasten running time, suitable for real-time AMC applications.

Lowering the PAPR of the optical OTFS-based 6G radio with a hybrid PTS-PSO genetic approach

Orthogonal Time Frequency Space (OTFS) is regarded as one of the best contenders for sixth-generation (6G) radio systems due to its ability to obtain excellent performance in high-speed scenarios. Peak-to-average power ratio (PAPR) significantly impacts and degrades the efficiency of the power amplifier used in OTFS-based 6G systems. The proposed article presents a genetic hybrid algorithm, Partial transmission sequence-particle swarm optimization (PTS-PSO), obtaining an optimal PAPR performance with low computation complexity. The PSO generates the best phase factor compared to the conventional phase generation method of PTS, making PTS-PSO more effective. The impacts such as PAPR, bit error rate (BER), power spectral density (PSD), and complexity of the proposed PTS-PSO are compared with the conventional selective mapping (SLM) and PTS methods for 64, 256, and 512 OTFS sub-carriers. The projected PTS-PSO attained a PAPR and PSD gain of 1–6 dB and − 540 while preserving the BER performance. The experimental results demonstrate that the projected PTS-PSO outperforms the conventional SLM and PTS algorithms with trivial intricacy.

Hadamard and Riemann Matrix‐BasedSLMforPAPRReduction inOTFSSignal

ABSTRACTIn this letter, we study the peak‐to‐average power ratio (PAPR) reduction and bit error rate (BER) performances of the Hadamard and Riemann matrix‐based selected mapping (SLM) technique for Orthogonal Time Frequency Space (OTFS) signals. Unlike the conventional phase sequence based on , which requires the entire sequence to extract the original signal at the receiver, the Hadamard and Riemann matrix‐based SLM techniques require only the row index of the matrix, reducing the additional information necessary to extract the signal. Simulation results are presented to verify the PAPR and BER performance. The results are also compared with the existing normalizedμ‐law, rootingμ‐law, and conventional SLM methods. The results demonstrate that the Riemann‐based SLM technique shows significant performance improvement.

Throughput improvement in ACO-OFDM-based VLC systems using noise cancellation and precoding techniques

One of the primary challenges faced by visible light communication (VLC) systems employing optical orthogonal frequency division multiplexing is the peak-to-average power ratio (PAPR). This study is dedicated to designing, simulating, and evaluating bit error rate (BER) and PAPR reduction methods tailored for the VLC broadcasting system. The asymmetric clipped optical orthogonal frequency division multiplexing (ACO-OFDM) scheme is highlighted in this work for its impressive performance. Therefore, the proposed PAPR mitigation methodologies applied to ACO-OFDM. The proposed PAPR reduction strategy involves 5 distinct precoding methodologies. The PAPR was mitigated by 3.485 dB after applying the DST precoding methodology. Still, the WHT precoding methodology can achieve PAPR reduction by 1.131 dB, without BER performance degradation, with respect to the conventional ACO-OFDM system. Furthermore, the work addresses another challenge in VLC systems: the bit error rate (BER). This is accomplished by introducing approaches to Time Domain Noise Cancelation and Frequency Domain Noise Cancelation (FDNC). The BER performance of these 2 receiver models is nearly the same. The simulation results indicate the system performance enhancement after applying noise cancellation approaches by 1.65 dB at the 4-QAM modulation scheme and 2.97 dB at the 1024-QAM modulation scheme. The 16-QAM modulation scheme, after applying DST and WHT methodologies alongside noise cancellation approaches, can enhance both PAPR by 20.83% and 6.76%, but the Eb/N0 performance enhancement by 10.10% and 14.64%, respectively. Additionally, the effectiveness and validity of the proposed schemes are verified by comparing them with relevant literature reviews on PAPR reduction techniques and selecting an optimal choice among them.

Performance analysis of MIMO FSO adaptive mode switching in Malaga turbulent channels with pointing error

MIMO FSO (Free Space Optical) systems can provide high data rates through spatial multiplexing or improve transmission reliability using spatial diversity, but atmospheric turbulence is a bottleneck that restricts communication performance. Adaptive transmission technology can effectively suppress the influence of turbulence and improve communication performance. In this paper, switching between spatial multiplexing and diversity is proposed as an adaptive transmission technology for MIMO links to improve the diversity performance of spatial multiplexing of FSO systems. The switching criterion is based on the Minimum Euclidean Distance (MED) of the spatial mapping scheme. The MED expressions for two spatial modes at the receiver are derived, and the bit error rate (BER) approximations are provided, respectively. We evaluate the BER performance of spatial multiplexing and spatial diversity schemes, respectively, taking into account the joint effects of turbulence strengths, pointing error and path loss. To choose the optimal adaptive switching strategy for the system in different signal-to-noise ratio (SNR) ranges, a lookup table for the adaptive switching statistical SNR threshold was created based on the BER curve corresponding to the minimal Euclidean distance. The results show that compared with fixed spatial mode systems, adaptive spatial mode switching systems can achieve significant BER performance gains. The Demmel condition number of matrix channels is considered to provide a sufficient condition for spatial multiplexing to be superior to spatial diversity.

A Hybrid Network Integrating MHSA and 1D CNN–Bi-LSTM for Interference Mitigation in Faster-than-Nyquist MIMO Optical Wireless Communications

To mitigate inter-symbol interference (ISI) caused by Faster-than-Nyquist (FTN) technology in a multiple input multiple output (MIMO) optical wireless communication (OWC) system, we propose an ISI cancellation algorithm that combines multi-head self-attention (MHSA), a one-dimensional convolutional neural network (1D CNN), and bi-directional long short-term memory (Bi-LSTM). This hybrid network extracts data features using 1D CNN and captures sequential information with Bi-LSTM, while incorporating MHSA to comprehensively reduce ISI. We analyze the impact of antenna numbers, acceleration factors, wavelength, and turbulence intensity on the system’s bit error rate (BER) performance. Additionally, we compare the waveform graphs and amplitude–frequency characteristics of FTN signals before and after processing, specifically comparing sampled values of four-pulse-amplitude modulation (4PAM) signals with those obtained after ISI cancellation. The simulation results demonstrate that within the Mazo limit for selecting acceleration factors, our proposal achieves a 7 dB improvement in BER compared to the conventional systems without deep learning (DL)-based ISI cancellation algorithms. Furthermore, compared to systems employing a point-by-point elimination adaptive pre-equalization algorithm, our proposal exhibits comparable BER performance to orthogonal transmission systems while reducing computational complexity by 31.15%.

Joint PAPR reduction with channel estimation for OFDM-based VLC systems

Abstract This paper presents a new combination of channel estimation (CE) methods and peak-to-average power ratio (PAPR) reduction techniques for orthogonal frequency division multiplexing (OFDM)-based visible light communication (VLC) systems. We first propose iterative clipping and filtering to minimize the PAPR of optical OFDM signals. Then, we introduce a computationally efficient, high-performance channel estimation approach using block-type pilots with modified clipped signals. The proposed method integrates clipping with three distinct CE techniques, resulting in both significant PAPR reduction and enhanced bit error rate (BER) performance. Among the CE methods evaluated, the expectation-maximization (EM) technique provides better BER results compared to other approaches. Simulation results confirm that the combined use of clipping and advanced CE methods leads to notable improvements in PAPR reduction and BER performance for OFDM-based VLC systems.

An efficient non-binary QC-LDPC coded modulation scheme for long-haul optical systems

Abstract Coded modulation (CM), which combines channel codes with high-dimensional modulation schemes, is an attractive technique to improve the spectral efficiency in high-speed optical transmission systems. Non-binary low-density parity check (NB LDPC) codes can provide larger coding gains with smaller codeword lengths compared to their binary counterpart, in addition to reducing the latency of the system. The majority of works based on NB LDPC CM focus on bit-interleaved CM (BICM) and the widely used additive white Gaussian noise (AWGN) channel model. However, the Gaussian channel model is not a realistic model for long-haul intensity-modulated direct-detection (IM/DD) optical systems using erbium-doped fiber amplifiers. In this paper, it is mathematically proved that noise in the received signals after photodetection can be more accurately represented using chi-squared distribution. The efficiency of CM depends on the mapping between coded symbols and the constellation signal points of the modulation scheme. Hence, a symbol interleaved CM with subcarrier modulation for NB LDPC codes based on the proposed channel model is presented in this paper to improve the bit-error rate (BER) performance. The simulation results show that the proposed CM for NB LDPC codes with M-ary quadrature amplitude modulation schemes provides better performance than BICM. The analysis of the error performance of the proposed system gives a coding gain of 1 dB at a BER of 10−7 compared to that of the AWGN channel model. The performance improvement of the system is also evaluated in terms of spectral efficiency and link distance.

BER Analysis of Underlay Cooperative Cognitive Radio-based NOMA System

Background: The integration of Cooperative Communications (CC), Cognitive Radio (CR) technology, and Non-Orthogonal Multiple Access (NOMA) techniques, termed Cooperative Cognitive Radio used NOMA (CCR-NOMA) systems, has emerged as a promising solution to address spectrum scarcity and connectivity challenges anticipated in sixth generation (6G) networks. Aim: This studyaims to investigate the Bit Error Rate (BER) performance of underlay CCRNOMA systems. Methods: We derive precise closed-form expressions for BER at distant users under perfect and imperfect Channel State Information (CSI) conditions. These mathematical formulations are validated through Monte Carlo simulations. Results: Our results indicate that the near user CU! exhibits superior performance compared to the far user CU!. Additionally, distant users utilizing the CCR-OMA protocol demonstrate better BER performance than those employing the CCR-NOMA protocol. Conclusion: The presence of imperfect CSI adversely affects BER performance. Moreover, the derived closed-form expressions for BER in the investigated system align well with Monte Carlo simulations. These findings provide valuable insights for optimizing the performance of CCR-NOMA systems in real-world scenarios.

A novel differential chaos shift keying system based on joint time slot and code index of carrier phase modulation

This paper proposes a novel differential chaos shift keying (DCSK) system that utilizes carrier phase modulation in combination with time slot and code index modulation, referred to as CP-TCIM-DCSK system, to achieve high data rate transmission. In the proposed CP-TCIM-DCSK system, the carrier modulated by the carrier phase is used to transmit the information-bearing signal. In addition to physically transmitted information bits, extra information bits are conveyed through time slot and Walsh code modulation, as well as carrier phase modulation, making full use of the benefits of multidimensional modulation. To successfully estimate carrier phase bits and code index bits, an effective joint detection algorithm for carrier phase and code index tailored for the CP-TCIM-DCSK system is introduced. The theoretical Bit Error Rate (BER) expressions for the CP-TCIM-DCSK scheme are derived for both Additive White Gaussian Noise (AWGN) and multipath Rayleigh fading channels. Furthermore, a comparison of data rates, energy efficiency, and complexity between the CP-TCIM-DCSK system and the most advanced systems in the same category at present is conducted. The results validate the accuracy of theoretical analysis through simulation and demonstrate that the proposed scheme outperforms its competitive systems in terms of BER performance.

Enhancing MIMO-VLC system performance using reflective phase change materials

Abstract In this paper, the impact of phase change materials (PCM) as reflecting surfaces on the bit error rate (BER) performance of multiple-input multiple-output (MIMO) visible light communication (VLC) systems has been investigated. The optical properties of PCM, including absorption and reflection characteristics have been analyzed to optimize the design and functionality of PCM-based VLC systems. The current study investigates the BER performance of 4 × 4 and 8 × 8 MIMO-VLC systems using non-line of sight (NLoS) signal under varying refractive index, temperature, and incidence angle conditions. Additionally, different types of PCM has been assessed, such as organic compounds, salt hydrates, and paraffin wax, to determine their suitability for implementation in MIMO-VLC systems.

A low-complexity error-feedback lattice-equalizer with phase tracking for underwater acoustic communications.

Recursive least squares (RLS)-based equalizers are hindered by their high complexity in underwater acoustic (UWA) communications. This article proposes an adaptive equalizer with a phase tracking method for the UWA communication, named the error-feedback lattice-equalizer (EFLE). First, we derive the algorithm for recursively solving the least squares problem from EFLE, introducing a lattice structure using time and order updates, thereby reducing the complexity to be linearly related to its length. The error-feedback mechanism used in computing reflection coefficients ensures the numerical stability of the algorithm. By focusing on the rapid tap rotation in time-varying channels, we design phase tracking in EFLE to further improve equalization performance. To verify the bit error rate (BER) performance of the proposed EFLE, we study the UWA communication system and conduct UWA simulations and at-sea experiments. Comparisons include linear complexity equalizers such as least mean square (LMS), leaky LMS, least mean mixed-norm, and ϵ-normalized LMS equalizers, and quadratic complexity RLS equalizers. At-sea experiment results show that the BER performance of EFLE significantly outperforms its counterparts.

On the impact of interlayer misalignment for dual-layer data detection in three dimensional magnetic recording

Three-dimensional magnetic recording (3DMR) is a crucial technology for significantly increasing the storage capacity of hard disk drives (HDDs). However, the presence of inter-symbol interference (ISI), intertrack interference (ITI), and interlayer interference (ILI) poses significant challenges to the accurate detection of data stored on multiple layers. This study addresses the impact of interlayer misalignment on the bit error rate (BER) performance in 3DMR systems. We evaluate the performance based on a neural network estimator for reconstructing the top-layer read response signal using feedback from a Viterbi detector. This enables the separation of bottom-layer signals by subtraction from the mixed readback signal. We introduce a dual-layer partial response maximum likelihood (PRML) detector for simultaneous bit retrieval from both layers. Furthermore, we investigate methods of a per-layer binary classifier and a dual-layer four-class classifier based on neural networks. Our study demonstrates the BER performance of these detection schemes influenced by the interlayer misalignment, especially when the offset is 0, 10%, 50%, and 90% of the bit dimensions between the two layers. The results show that the neural network-based reconstruction and separation method achieves better bottom-layer BER performance under a slight interlayer misalignment. The BER performance benefits more from a mild downtrack offset than the crosstrack offset. The neural network-based separation detection and the dual-layer PRML achieve the lowest top-layer BER and the worst bottom-layer BER when the interlayer misalignment is half a bit.

A noncoherent chaotic communication system with multidimensional index modulation based on cyclic permutation grouping

With the surge in technological advancements and application demands, the study of high-data-rate communication systems has become increasingly significant. To enhance the data transmission rate and spectral efficiency of traditional DCSK systems, we have designed a differential chaos shift keying (DCSK) system with multidimensional index modulation based on cyclic permutation grouping (CPG-MIM-DCSK). Multidimensional index resources are efficiently combined by the CPG-MIM-DCSK system using the proposed cyclic permutation grouping method. In the CPG-MIM-DCSK system, both selected and unselected subcarriers, as well as selected and unselected time slots, are distinguished through different groups of cyclic permutations. Permutation, carrier, and time slot resources are fully utilized by this modulation method, thereby enhancing the data rate and spectral efficiency of traditional DCSK systems. The theoretical Bit Error Rate (BER) expressions of the CPG-MIM-DCSK system under Additive White Gaussian Noise (AWGN) and multipath Rayleigh fading channels are derived. The data rate, complexity, and spectral efficiency of the CPG-MIM-DCSK system are covered in further analysis. The simulation results highlight the superiority of the CPG-MIM-DCSK system in terms of data rate and spectral efficiency. Additionally, the proposed CPG-MIM-DCSK system exhibits better BER performance in both Gaussian and multipath Rayleigh fading channels compared to its comparative systems.

Transmission Diversity by Alamouti-Coding, Propagation Control by IRS in CDMA-FBMC-OQAM System

This manuscript suggests a modulation scheme for exploiting transmission diversity by integrating Alamouti coding and controlling the transmission by intelligent reflecting surface (IRS) in code division multiple access filter bank multicarrier offset quadrature amplitude modulation (CDMA-FBMC-OQAM) system, a promising technique for future-generation wireless communication. To neutralize the impact of channel phases, the IRS elements are in charge of intelligently adjusting the incident signal phases. By maximizing the signal-to-noise-ratio (SNR) of the received signal, the bit-error-rate (BER) performance is improved. By changing the number of IRS elements, taking into account various channel scenarios and modulation schemes, we compare the BER performance of the proposed system with that of the conventional Alamouti coded CDMA-FBMC-OQAM system in simulation results. The findings demonstrate that the IRS-assisted Alamouti coded CDMA-FBMC-OQAM transmission is a feasible choice for future-generation wireless communication systems.

Polar coded SCMA-OCDM based on chaotic scrambled SLM.

In this work, the polar coded sparse code multiple access (SCMA) scheme based on chaotic scrambled selective mapping (CS_SLM) is proposed for future passive optical networks (PONs). The original bits are coded by polar and mapped into constellation symbols by sparse code. Then orthogonal chirp division multiplexing (OCDM) modulation is adopted which has better anti-interference ability than orthogonal frequency division multiplexing (OFDM). At the receiver, the joint iterative detection and decoding for polar and SCMA is used to further improve the BER performance. The CS_SLM is helpful to improve the reliability and security, while keeping high spectral efficiency of SCMA-OCDM modulation. A 49.42 Gb/s coded SCMA-OCDM PON over 2 km seven-core fiber is demonstrated in the experiment. The results show that the SCMA-OCDM scheme gets a receiver sensitivity of 0.8 dB at a bit error rate (BER) of 3.8 × 10-3, compared with SCMA-OFDM. Because of peak to average power ratio (PAPR), the polar coded SCMA-OCDM based on CS_SLM is compared with clipping and filtering (CAF) method, about 2.08 dB receiver sensitivity gain is obtained when BER is lower than 10-5. The polar coded SCMA-OCDM based on CS_SLM also takes security into the consideration, due to the downlink broadcasting of PON. It can be a promising candidate for the next generation PONs.