Low Peak-to-average Power Ratio Research Articles

Low PAPR Filtered OFDM using Modified Selective Mapping

Wireless Communication has been witnessing generational change in the span of eight to ten years since it came in existence. From generation 1G to 3G and from 4G to 5G the telecommunication world has seen significant improvements along with enhanced performance with every passing year. The objective of research is to comprehensive study of Filtered Orthogonal Frequency Division Multiplexing (F-OFDM) as a promising waveform option for fifth-generation (5G) communications, distinguished by its capacity to suppress out-of-band emission (OOBE) and accommodate asynchronous transmission. Though there are many advantages but the challenge of a high peak-to-average power ratio (PAPR) among new waveform candidates can’t be ignored. To address this problem, the selective mapping technique is used as a key method to alleviate the elevated PAPR trend within multicarrier systems. This research put emphasis on applying selective mapping technique to overcome the high PAPR values in an F-OFDM system with different windowed filters such as kaiser, Nuttles blackman harris and Root raised cousine followed by a proposed Modified Selective mapping technique for further improved performance in terms of PAPR for the Filtered OFDM for different window functions in comparison with the conventional OFDM system, SLM F-OFDM system. Furthermore, PAPR performance is evaluated for all the three-system using the different window techniques analyzed for both systems, both with and without the SLM technique and Modified SLM technique to mitigate the PAPR disadvantage of the Filtered OFDM system. Simulation results underscore that F-OFDM enhanced by SLM and MSLM outperforms OFDM across PAPR.

DLLBVS: Design of a High-Efficiency Deep Learning based Low-BER Video Streaming Model for High-Noise Wireless Networks

Design of video streaming models for high-noise networks is a multimodal process that requires efficient channel modelling, noise analysis, error-specific stream control, intelligent data augmentation, etc. This article proposes design of a high-efficiency deep learning based low-BER (Bit Error Rate) Video streaming model for high-noise wireless networks. The proposed model initially uses a Long-Short-Term Memory (LSTM) block for estimation of frame level features, and then uses Orthogonal Frequency Division Multiple Access (OFDMA) based modulation platform for transmission and reception of processed video frames. The OFDMA model is cascaded with a chaotic communication module, which assists in improving data fidelity under different noise conditions. The chaotic communication module is optimized using Grey Wolf Optimizer (GWO), which assists in setting up its hyperparameters for better efficiency under real-time communication scenarios. Video frames were pre-processed using Dual Neural Networks that assisted in estimation of differential frame information sets. Due to estimation of this differential frame information, streaming speed is improved, which assists in increasing number of frames transmitted per second, thereby improving streaming performance for different video types. This frame information is further processed by an iterative Gated Recurrent Unit (GRU) based VARMAx Model, which assists in predicting frame removal instances, thus assisting in faster & low error communications. The GRU VARMAx Model optimizes data flow, thus reducing congestion and improving throughput. The model was tested under AWGN (Additive While Gaussian Noise), Rayleigh, & Rician channel types, and its efficiency was compared with standard streaming techniques in terms of communication delay, Bit Error Rate, Peak to Average Power Ratio (PAPR), throughput, communication jitter and computational complexity levels. Based on this comparison it was observed that the proposed model showcased 3.5% lower communication delay, 8.3% lower BER, 5.9% lower PAPR, 10.5% higher throughput, 3.9% lower jitter and 6.4% lower computational complexity, which makes it highly useful for a wide variety of real-time streaming scenarios.

PAPR reduction using model‐driven hybrid algorithms in the 6G NOMA waveform

AbstractIn the evolving landscape of sixth‐generation (6G) network technologies, Non‐Orthogonal Multiple Access (NOMA) systems are pivotal for achieving enhanced spectral efficiency and network capacity. However, a significant challenge in NOMA systems is the high Peak‐to‐Average Power Ratio (PAPR), which undermines system efficiency by necessitating high‐power amplifiers (HPAs) to operate in their less efficient, non‐linear range. Addressing this, we introduce a novel hybrid approach, the Selective Mapping‐Circular Transformation Method (SLM‐CTM), which ingeniously amalgamates the strengths of Selective Mapping (SLM) and the Circular Transformation Method (CTM) to mitigate PAPR issues. SLM is renowned for its peak power reduction capabilities without adding to system complexity, whereas CTM is valued for its simplicity and controlled signal distortion. The proposed SLM‐CTM strategy employs a blend of linear and nonlinear techniques to effectively lower PAPR in non‐orthogonal NOMA configurations, thereby reducing high‐power peaks while simultaneously enhancing signal quality. This paper delineates the application of the SLM‐CTM algorithm to evaluate critical NOMA parameters such as Power Spectral Density (PSD), Bit Error Rate (BER), and PAPR. Simulation results highlight the efficacy of SLM‐CTM over conventional SLM, demonstrating a significant throughput improvement of 3.2 dB and a PAPR reduction of 4.6 dB, underscoring the potential of SLM‐CTM in elevating the performance of NOMA systems within 6G network.

A Novel Alternating μ-Law Companding Algorithm for PAPR Reduction in OFDM Systems

Orthogonal frequency division multiplexing (OFDM) inherits multi-carrier systems’ inevitable high peak-to-average power ratio (PAPR) problem. In this paper, a novel alternating companding technique is proposed to combat the harassment of high PAPR. The sequential μ-law companding (SULC) and a tone with a lower PAPR result in only partial tones needing companding. The SULC scheme’s PAPR and bit error rate (BER) performance has been balanced and improved. However, the computational complexity is still too high to be implemented. Therefore, this study sorted the transmission signals according to their amplitudes. Then, all the tones are divided into two groups by estimating the rough companding amount (around 54% of the subcarriers), using traditional parallel companding for the first group and the other group only by partial μ-law companding. This alternating μ-law companding (AULC) is proposed to improve the PAPR performance and simultaneously reduce complexity. Simulation results show that the proposed AULC method appreciably reduces the PAPR by about 5 dB (around 45%) compared with the original μ-law at complementary cumulative distribution function (CCDF) equal to 10−4. Moreover, it only requires a moderate complexity to outperform the other companding schemes without sacrificing the BER performance in the OFDM systems.

A mathematical analysis of the PAPR in the NOMA waveform using SLM algorithm for 64-QAM

In Non-Orthogonal Multiple Access (NOMA) technology, a paradigm shift in wireless communication is observed, as it allows numerous users to simultaneously transmit data over the same spectral resources in a non-orthogonal manner. Despite the advancements it brings to the table, NOMA is faced with a notable technical obstacle, that being the elevated Peak-to-Average Power Ratio (PAPR). Elevated PAPR levels can lead to less efficient use of power and a deterioration in the fidelity of the signal. We proposed a Selective Mapping (SLM) as a powerful solution to address this issue. SLM is a PAPR reduction technique that applies controlled phase rotations to the symbols of different users before transmission, aiming to minimize the PAPR of the combined signal. In the context of NOMA, the application of SLM offers several notable advantages. SLM modifies the Power Spectrum Density (PSD), leading to a more uniform and spectrally efficient power distribution over the frequency spectrum. This enhancement in spectral efficiency concurrently lowers the risk of disrupting nearby frequency channels. Moreover, SLM exerts a favorable influence on the Bit Error Rate (BER) in NOMA systems, which contributes to improved transmission accuracy. Utilizing SLM to achieve lower PAPR values significantly diminishes the probability of symbol errors, thus enhancing the dependability. Additionally, it has been observed that the method in question delivers an improvement in PAPR, BER, and PSD with gains of 2.2 dB, 4 dB, and -620 respectively, in comparison to traditional SLM techniques.

Symbol interferometry and companding transform for PAPR reduction of OTFS signal

AbstractThis paper presents methods for reducing the peak‐to‐average power ratio (PAPR) of the orthogonal time frequency space (OTFS) signal. These methods mainly consist of two operations: symbol interferometry (SI) and either ‐law or ‐law companding. SI spreads the data of one OTFS symbol onto all symbols and is implemented using a simple inverse fast Fourier transform operation on each OTFS symbol. During the second operation, the PAPR of the OTFS signal is significantly reduced. For our performance analysis, the complementary cumulative distribution function, probability density function, and bit error rate are illustrated through simulations performed in MATLAB. The performance is also analyzed using a solid‐state power amplifier at the transmitter and compared with OTFS, ‐law‐based OTFS, and SI OTFS systems. The results indicate that the proposed OTFS system achieves a low PAPR.

Integrated Sensing and Communication With Delay Alignment Modulation: Performance Analysis and Beamforming Optimization

Delay alignment modulation (DAM) has been recently proposed to enable manipulable channel delay spread for efficient single- or multi-carrier communications. In particular, with perfect delay alignment, inter-symbol interference (ISI) can be eliminated even with single-carrier (SC) transmission, without relying on sophisticated channel equalization. The key ideas of DAM are <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">delay pre-compensation</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">path-based beamforming</i> , so that all multi-path signal components may arrive at the receiver simultaneously and be superimposed constructively, rather than causing the detrimental ISI. Compared to the classic orthogonal frequency division multiplexing (OFDM) transmission, DAM-enabled SC communication has several appealing advantages, including low peak-to-average-power ratio (PAPR) and high tolerance for Doppler frequency shift, which renders DAM also appealing for radar sensing. Therefore, in this paper, DAM is investigated for integrated sensing and communication (ISAC) systems. We first study the output signal-to-noise ratios (SNRs) for ISI-free SC communication and radar sensing, respectively, and then derive the closed-form expressions for DAM-based sensing in terms of the ambiguity function (AF) and integrated sidelobe ratio (ISR). Furthermore, we study the beamforming design problem for DAM-based ISAC to maximize the communication SNR while guaranteeing the sensing performance in terms of the sensing SNR and ISR. Finally, we provide performance comparison between DAM and OFDM for ISAC, and it is revealed that DAM signal may achieve better communication and sensing performance, thanks to its low PAPR, reduced guard interval overhead, as well as higher tolerance for Doppler frequency shift. Simulation results are provided to show the great potential of DAM for ISAC.

PAPR and BER Analysis in FBMC/OQAM System with Pulse Shaping Filters and Various PAPR Minimization Methods

Filter Bank Multicarrier with Offset Quadrature Amplitude Modulation(FBMC/OQAM) system design based on frequency sampling prototype filter takes into account the low frequency utilization of Orthogonal Frequency Division Multiplexing(OFDM) caused by adding Cyclic Prefix(CP). The CP decreases spectral efficiency and increases Peak to Average Power Ratio(PAPR). FBMC is an OFDM enhancement. In this paper to reduce the PAPR, we explained companding methods. We have proposed an FBMC that makes use of prototype pulse shaping filters which can be adjusted to meet system requirements in order to defeat these limitations. Due to its significant effect on the performance of FBMC-OQAM, choosing the right filter is crucial. Different prototype filters are used to investigate the performance of the FBMC-OQAM in this paper. Using the validated system, it was found that frequency utilization is more and good out-band suppression as well as an excellent application value in 5G technology. By using ?-law companding method, FBMC/OQAM provides better performance. It produces low PAPR, low out of band(OoB), high BER performance, less computational complexity and high spectral efficiency as compared to other methods.

Time-Frequency Domain Non-Orthogonal Multiple Access for Power Efficient Communications

We propose a power efficient non-orthogonal multiple access (NOMA) scheme suitable for Internet of Things (IoT) and device-to-device (D2D) communications. OFDM-based power-domain NOMA (PD-NOMA) is one of the promising approaches to achieve simultaneous connections of massive devices. Nevertheless, the problem of high peak-to-average power ratio (PAPR) is a major challenge, since power amplifier (PA) efficiency is a critical factor for IoT and D2D devices consisting of low-cost hardware components. This paper overcomes this problem by introducing time-frequency domain NOMA (TF-NOMA), where OFDM and DFT-spread OFDM (DFT-s-OFDM) are superposed over the time-frequency domain. By utilizing the low PAPR property achieved by DFT-precoding, TF-NOMA can efficiently reduce the PAPR of the downlink signal transmitted by the base station (BS) as well as the uplink signals of the devices located far from BS. As a result, the proposed TF-NOMA can operate with higher PA efficiency than the conventional OFDM-based PD-NOMA. Furthermore, the insertion of DFT-precoding with the aim of PAPR reduction also enhances the error propagation resistance due to the resulting Gaussian mixture signal property. Throughout the mathematical analysis and computer simulations, we demonstrate that TF-NOMA achieves better error rate performance than the conventional PD-NOMA with significant improvement of PA efficiency.

New sets of non-orthogonal spreading sequences with low correlation and low PAPR using extended Boolean functions

Extended Boolean functions (EBFs) are one of the most important tools in cryptography and spreading sequence design in communication systems. In this paper, we use EBFs to design new sets of spreading sequences for non-orthogonal multiple access (NOMA), which is an emerging technique capable of supporting massive machine-type communications (mMTC) in 5 G and beyond. In this work, first p-ary complementary sequences are constructed using EBFs and then, these sequences are used to design new sets of non-orthogonal spreading sequence sets having very low coherence and peak to average power ratio (PAPR). The proposed spreading sequence sets are capable of supporting a large number of active devices simultaneously. In fact, for a p-ary spreading sequence set, we theoretically achieve an overloading factor of 2p, where p is an odd prime. Specifically, for $$p=3$$ , we achieve an overloading factor of 6, which cannot be achieved through the existing constructions till date.

A Novel PAPR Reduction Scheme for Low-Cost Terminals in 6G

This paper presents a low peak-to-average power ratio (PAPR) modulation scheme and demodulation method for low-cost terminals in sixth-generation (6G), which is called one plus delay (1 + D) pi/2(N + 1) BPSK. Explicitly, the modulation scheme is first generated based on pi/2 BPSK, then proceeded by interpolation and (1 + D) transformation. Simulation results show that the proposed (1 + D) pi/2(N + 1) BPSK scheme has lower PAPR and smaller out-of-band leakage in discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM). Moreover, better performance can be attained by increasing the value of N. Finally, similar block error ratio (BLER) performance can be obtained at the same spectral efficiency of the conventional pi/2 BPSK scheme.

Multi-antennas PAPR Reduction for FBMC/OQAM System

Background: The filter bank multicarrier (FBMC) with offset quadrature amplitude modulation (OQAM) is a promising future generation of wireless systems. However, like multicarrier modulations (MCM), FBMC/OQAM has a high peak-to-average power ratio (PAPR), which allows the FBMC/OQAM signal to pass through the nonlinear region of the high-power amplifier (HPA) in the time domain and causes in-band and out of band (OOB) distortion. Methods: In this paper, a new method to overcome this problem called multi-antennas PAPR (MAP) reduction is proposed. It consists of using I antennas in transmission and reception to transmit I FBMC/OQAM sub-signals with low PAPR. The complementary cumulative distribution function (CCDF), the bit error rate (BER), and the energy efficiency are used to evaluate the method's performance. Results: The simulation results showed that the new technique can reduce the PAPR of the original signal by more than half, achieve BER comparable to that of the original signal without HPA, and when the input back-off (IBO) equals 3dB, the error vector magnitude (EVM) result can be reduced from 19% to 7%. Conclusion: The PAPR, BER, and EVM of MAP technique are much better than the original system.

Performance Optimization of Universal Filtered Multicarrier Technique for Next Generation Communication Systems

Next generation communication systems require better performance to support high - bandwidth, peak data rate, spectral efficiency, mobility, connection density, positioning accuracy, etc. Investigation on efficient modulation technique for next generation has become very important so as to meet its expectations. In this paper performance optimization of universal filtered multicarrier (UFMC) technique for next generation communication systems have been investigated. Dolph-Chebyshev (DC) and Kaiser-Bessel- derived (KBD) filters have been used to optimize power spectral density, channel equalization, bit error rate, and peak to average power ratio (PAPR). It has been observed that KBD filter response is comparatively better than DC filter. Effect of filter length also influences the system performance, filter with bigger length improves performance at the cost of computational complexity. Performance of UFMC has been compared with that of orthogonal frequency division multiplexing (OFDM) technique. The present work of investigations on UFMC that is based on subband filtering is our original research work that has been carried out for its suitability for next generation communication systems. It has simple design structure, lower computational complexities and better performance in terms of BER compared to OFDM and f-ODFM systems. It has comparatively low PAPR than GFDM and FBMC techniques.

Security and Energy Efficiency: Breaking the Barriers of High Peak-to-Average Power Ratio and Disguised Jamming in NextG IoT System Design

As a popular modulation technique in wireless communications, orthogonal frequency-division multiplexing (OFDM) has two major disadvantages—one is its high peak-to-average power ratio (PAPR), which causes nonlinear distortion, lower power efficiency, and performance losses; the other is its fragility under hostile jamming attacks, where the authorized user asciitext’s signal is deliberately interfered by the adversary, leading to communication failures. In this article, first, we reintroduce the IFFT-relocated OFDM (IR-OFDM), which is essentially a single-carrier system with frequency-domain equalization. By relocating the inverse fast Fourier transform (IFFT) block in OFDM from the transmitter to receiver, IR-OFDM can completely liberate OFDM from the barriers of high PAPR while achieving the same spectral efficiency. Second, to combat hostile jamming, especially disguised jamming, where the jamming is highly correlated with the authorized signal, we propose a securely precoded IR-OFDM (SP-IR-OFDM). By integrating the advanced encryption standard (AES) into IR-OFDM transceiver design, we obtain a random (or dynamic) constellation. The shared secure randomness introduced by AES breaks the symmetry between the authorized signal and the jamming interference and, hence, ensures reliable performance of the system under disguised jamming. The efficiency and robustness of IR-OFDM and SP-IR-OFDM are demonstrated through simulation examples. It is shown that IR-OFDM can deliver comparable or better performances than OFDM under multipath propagation, and SP-IR-OFDM can achieve strong resistance under disguised jamming while enjoying low PAPR and relatively high spectral efficiency. Our result indicates that, potentially, SP-IR-OFDM can serve as a promising modulation candidate for next-generation secure and energy-efficient high-speed communications, especially for the resource-constrained Internet of Things (IoT) networks.

Peak-Average-Power Ratio Techniques for 5G Waveforms Using D-SLM and D-PTS

Multicarrier Waveform (MCW) has several advantages and plays a very important role in cellular systems. Fifth generation (5G) MCW such as Non-Orthogonal Multiple Access (NOMA) and Filter Bank Multicarrier (FBMC) are thought to be important in 5G implementation. High Peak to Average Power Ratio (PAPR) is seen as a serious concern in MCW since it reduces the efficiency of amplifier use in the user devices. The paper presents a novel Divergence Selective Mapping (DSLM) and Divergence Partial Transmission Sequence (D-PTS) for 5G waveforms. It is seen that the proposed D-SLM and PTS lower PAPR with low computational complexity. The work highlighted a combination of multi-data block partial transmit schemes along with tone reservation. In this, an overlapping factor is used to determine the number of data blocks for every group. Here, considering only those data blocks that have minimum signal power, the use of DSLM and DPTS are required to eliminate the segment’s peaks. Simulation results reveal that the suggested hybrid technique proves to be better than the conventional PTS scheme. Furthermore, the power saving performance of FBMC and NOMA is compared with the Orthogonal Frequency Division Multiplexing (OFDM) waveform.

Simulation Analysis of Low PAPR FFT-based OFDM Through Nakagami Channel

In response to the inefficiency of power amplifier in conventional Orthogonal Frequency Division Multiplexing (OFDM) system, a low Peak-to-Average Power Ratio (PAPR) scenario can be obtained by implementing several PAPR reduction techniques. Partial Transmit Sequence (PTS) is a well-known instance to provide zero distortion for the system, while clipping is one of the simplest methods but it is sacrificing the error rate performance. In this work, Authors focused on analyzing the implementation of PTS and Palm Date Leaf clipping technique on OFDM system with 16-, 64-, 256-, and 1024-QAM under various Nakagami channel. In addition, the High-Power Amplifier (HPA) was also considered by using Solid State Power Amplifier (SSPA) model. It was found that linear HPA serves as the lower boundary for non-linear HPA, and system under high saturation level performs similarly. In physical properties, high saturation level is equivalent to higher power consumption in amplifier. Thus, optimal level was obtained by considering taking the one with moderate BER performance. After the system’s PAPR was reduced, the optimum saturation level of HPA was found to be 5 dB, 8 dB, 9 dB, and 11 dB for each Quadrature Amplitude Modulation (QAM) under Nakagami channel with m value of 1.5. However, this value was found to be ample for lower m value such as 1 or 0.7. In this case, the system required lower saturation level on the HPA for Nakagami channel with lower m value.

OFDM-based 2D generalized optical quadrature spatial modulation for MIMO-OWC systems

An innovative scheme, named orthogonal frequency division multiplexing (OFDM)-based two-dimensional (2D) generalized optical quadrature spatial modulation (GOQSM), is proposed for bandlimited multiple-input multiple-output optical wireless communication (MIMO-OWC) systems. In this scheme, by way of combining two consecutive time slots into one time block, 2D GOQSM mapping can be executed in spatial domain and time domain. Therefore, more spatial bits can be transmitted, resulting in the increase of system spectral efficiency. Furthermore, discrete Fourier transform (DFT) spreading is further introduced in OFDM-based 2D GOQSM systems, so as to substantially reduce the peak-to-average power ratio (PAPR) of the transmitted signals. To evaluate and compare the performance of OFDM-based 2D GOQSM systems with other traditional systems, numerical simulations are conducted under various spectral efficiencies. The obtained simulation results prove that the proposed OFDM-based 2D GOQSM scheme with DFT spreading can achieve better bit error rate performance and lower PAPR than other benchmark schemes.

Multipath Analysis of Pruned DFT-Spread FBMC-OQAM in Underwater Acoustic Channels

During modulation, when each phase of subcarriers is the same or similar, the superimposed signal will be modulated by the same initial phase, resulting in a large instantaneous power peak, namely the higher peak-to-average power ratio (PAPR). After signals propagate through different paths, the interference is caused by the superposition of each component according to their respective phases, which distorts original signals or produces errors. To reduce the PAPR and resist the influence of long-time delays, we propose to employ the discrete Fourier transform spread filter bank multicarrier (DFT-spread FBMC) to achieve it. Different from general FBMC technologies, it adds a precoding matrix before the offset quadrature amplitude modulation (OQAM). By comparing with orthogonal frequency division multiplexing technology, this letter explores its PAPR performance under different delays. The results show that the pruned DFT-spread FBMC-OQAM has a lower PAPR and better performance in long-time delays underwater channels.

Variation Approach-Based Nonlinear Companding Scheme for PAPR Reduction in OFDM Systems

Orthogonal frequency division multiplexing (OFDM) continues to find vast deployment in current and next generation wireless communication systems. However, high peak-to-average power ratio (PAPR) is one of the major drawbacks in the OFDM system. In this paper, we develop a variation approach based nonlinear companding (VANC) scheme to reduce the PAPR in OFDM systems. It aims to find the probability density function (PDF) for OFDM signal amplitudes with low PAPR and low distortion compared with their original Rayleigh distribution. The target PDF is found by solving a variation optimization problem model, which is built to find the lowest PDF distortion with both average signal power and probability conservation constraint. To the best of our knowledge, it is the first time that the variation method is used to find companding function to address the high PAPR problem. We then propose an algorithm with companding operation based on quantized levels. Simulation results validate the performance superiorities of the proposed scheme to that of other typical companding schemes.

Interference optimized dual-functional radar-communication waveform design with low PAPR and range sidelobe

Dual-functional radar-communication system integrates the radar and communication functions into one system with a shared dual-functional waveform. In this paper, we focus on the problem of dual-functional waveform design under the peak-to-average power ratio (PAPR) constraint and low range sidelobe requirement. When the conventional schemes aim to minimize the multi-user interference (MUI) energy and maximize the similarity to the reference radar waveform, in our proposed method, a weighted summation objective function incorporated with the PAPR constraint and optimized MUI is constructed for the waveform design. Specifically, MUI is classified into destructive interference and constructive interference, while the latter is exploited as a free power for communication and is constrained to guarantee the communication quality-of-service (QoS). To tackle the resulting high order nonconvex problem, we develop an iteration algorithm based on the alternating direction method of multipliers (ADMM) procedure, which involves two quadratic programming subproblems in each iteration and is easy to solve with the current solver. Moreover, by taking the imperfect channel state information (CSI) into consideration, we further investigate the robust dual-functional waveform design problem with the bounded uncertainty of the CSI. Numerical simulations validate the effectiveness of the proposed method.