Universal Filtered Multi-Carrier System Research Articles

Analysis of Filtered Multicarrier Modulation Techniques Using Different Windows for 5G and Beyond Wireless Systems

In contemporary wireless communication systems, multicarrier modulation schemes have become widely adopted over single-carrier techniques due to their improved capacity to address challenges posed by multipath fading channels, leading to enhanced spectral efficiency. Orthogonal frequency division multiplexing (OFDM), a prevalent multicarrier scheme in 4G, is favored for its ease of implementation, interference resilience, and high data rate provision. But it falls short of meeting the requirements for 5G and beyond due to limitations such as out-of-band (OOB) emissions and cyclic prefixes. This paper introduces the filter bank multicarrier (FBMC) and universal filtered multicarrier (UFMC) with quadrature amplitude modulation (QAM) and phase shift keying (PSK) waveforms through Additive White Gaussian Noise channel (AWGN), Rayleigh fading channel and Rician channel. The objective of this paper is to enhance the performance of UFMC with reduced complexity through the new filtering approach for achieving optimal outcomes. The proposed scheme, incorporating Tukey filtering technique, demonstrates superior performance in reducing peak-to-average power ratio (PAPR) and improving bit error ratio (BER) compared to the original UFMC signal without necessitating additional power increments. Specifically, the UFMC system with Tukey filtering achieves a notable net gain of 5 dB. Simulation results demonstrate that utilizing various filter types in FBMC and UFMC systems, combined with QAM modulation, significantly reduces OOB emissions compared to conventional systems. In aspect to BER, Tukey window showed almost 10−6 at 15 dB SNR in UFMC which is better than FBMC.

Diffusion-assisted quantum noise stream cipher for physical layer security in UFMC

Universal filtered multicarrier (UFMC) is a promising multicarrier technologies due to its ability to suppress inter symbol interference, increase frequency band utilization and provide flexible adaptation. However, it is vulnerable to illegal eavesdropping in the point-to-multipoint access transmission. Quantum noise stream cipher (QNSC), a classical physical layer encryption scheme, is inherent matched with the UFMC system. However, its security mainly depends on the length of the basis states, which is limited by the performance of commercial high-speed digital-to-analog converters (DACs). In this work, we propose a diffusion-assisted quantum noise stream cipher (DA-QNSC) scheme to enhance the security. Here, we introduce artificial noise generated by hyperchaotic system to pseudo expand the distribution of quantum noise, which will make it more difficult for eavesdroppers to crack plaintext information violently. We experimentally demonstrate the encrypted 16/4096-QAM, 16/16384-QAM, 16/65536-QAM DA-QNSC signals over 30-km standard single mode fiber (SSMF) transmission. Compared to the conventional QNSC systems, the proposed method achieves a 3.6 times improvement in the security with the same DAC resolution and has negligible impact on bit error ratio (BER) performance. For the 16/65536-QAM signal, the number of masked symbols (NMS) are increased from 910 to 3270.

Filter design and power allocation in multi-user universal filtered multi-carrier (MU-UFMC) systems

Universal Filtered Multi-Carrier (UFMC) system has been introduced as a candidate for the new generation. UFMC is a multi-carrier system, which can overcome challenges in wireless communications. In fact, the advantages of multi-carrier systems over single-carrier systems include higher bandwidth gain and higher robustness against frequency-selective fading. Generally, most multi-carrier systems suffer from notoriously sensitive to symbol-time offset (STO) and carrier-frequency offset (CFO). However, since UFMC systems utilize subband filters, sensitivity to CFO and STO can be reduced by designing efficient subband filters. In this paper, filter design problem is addressed in order to mitigate interference caused by effect of CFO in a multi-user UFMC (MU-UFMC) system under fair optimization framework. Since filter design problem is formulated as a non-convex optimization problem, we present two different approach in order to solve it. In the first approach, the formulated problem is relaxed so that one is converted to a standard second-order-cone programming (SOCP). In the second approach, we present a proposed algorithm with low complexity based on some lemma and relaxation. Then power allocation problem is solved to maximize the minimum achievable rate among all the users in a MU-UFMC system. The simulation results show the proposed schemes for filter design and power allocation outperform the benchmark schemes.

Peak to Average Power Ratio Reduction in UFMC System Using Pre -Coding and Nonlinear Companding Techniques

Universal Filtered Multi-Carrier (UFMC) is a versatile fifth-generation communication technology that can be utilized in Internet of Things and Machine-to- Machine (M2M) communication to enhance connectivity and efficiency because of its spectral efficiency, low power consumption, reliability, and flexibility. The Internet of Things and Machine-to-Machine (M2M) communication enable devices to talk to each other, gather data, and make the world smarter and more efficient. However, the drawback of UFMC systems is they exhibit a very high peak -to-average-power-ratio which causes system Lower and latency on communication. Therefore, to lower the high peak -to-average-power-ratio of the UFMC system, this project proposes an efficient hybrid PAPR reduction approach that combines both non-linear companding techniques and precoding techniques. Key Words: Peak-to-average power ratio (PAPR), Hybrid PAPR reduction Techniques, Precoding Techniques, Non- Linear Companding Techniques (NCLTs), Universal Filtered Multi-Carrier (UFMC).

Analysis of Optimum Technique for PAPR Reduction in UFMC System

Abstract: The fifth Generation of communication has to support many applications like the Internet of Everything (IoE) and Machine Type Communication (MTC). The proposed universal filtered multi-carrier (UFMC) technique is one of the best techniques for fifth-generation (5G) communication. UFMC is expected to achieve low latency, robustness against synchronization errors and frequency offset, short-packet burst support, and reduce out-of-band (OoB) radiation that leads to higher spectral efficiency. Although the UFMC system offers many advantages as mentioned before, being a multicarrier transmission technology, it suffers from a high peak-to-average power ratio (PAPR), which degrades the efficiency of the HighPower Amplifier (HPA) and makes the UFMC transmitter inefficient. Therefore, an optimum PAPR reduction technique to reduce the high PAPR of the UFMC system has to be proposed. The proposed technique is a hybrid technique that consists of a combination of Generalized Chirp-Like (GCL) precoding and Selective-Mapping techniques (SLM). A comparative analysis of the performance of Generalized Chirp-Like precoding methods, SLM, and hybrid methods are by CCDF of the PAPR and the bit error rate (BER) and simulation results show that proposed SLM based GCL UFMC outperform the conventional techniques

Selective Mapping Scheme for Universal Filtered Multicarrier

The next step in mobile communication technology, known as 5G, is set to go live in a number of countries in the near future. New wireless applications have high data rates and mobility requirements, which have posed a challenge to mobile communication technology researchers and designers. 5G systems could benefit from the Universal Filtered Multicarrier (UFMC). UFMC is an alternate waveform to orthogonal frequency-division multiplexing (OFDM), in filtering process is performed for a sub-band of subcarriers rather than the entire band of subcarriers Inter Carrier Interference (ICI) between neighbouring users is reduced via the sub-band filtering process, which reduces out-of-band emissions. However, the UFMC system has a high Peak-to-Average Power Ratio (PAPR), which limits its capabilities. Metaheuristic optimization based Selective mapping (SLM) is used in this paper to optimise the UFMC-PAPR. Based on the cognitive behaviour of crows, the research study suggests an innovative metaheuristic optimization known as Crow Search Algorithm (CSA) for SLM optimization. Compared to the standard UFMC, SLM-UFMC system, and SLM-UFMC with conventional metaheuristic optimization techniques, the suggested technique significantly reduces PAPR. For the UFMC system, the suggested approach has a very low Bit Error Rate (BER).

Deep bidirectional LSTM for the signal detection of universal filtered multicarrier systems

Universal filtered multicarrier (UFMC) has emerged as a potential waveform contender of orthogonal frequency division multiplexing (OFDM) for the fifth generation (5G) and beyond wireless systems. In this paper, we propose a bidirectional long short-term memory (Bi-LSTM)-based detector for the UFMC system. The proposed detector directly detects the transmitted symbols using the deep learning (DL)-based training data. The system is first trained with the aid of training data and pilot symbols. The training tunes the DL-based network parameters. During the testing phase, the signal is detected using the trained network. The performance of the proposed scheme is compared with that of the DL-aided OFDM system, and with the signal detection strategies using the conventional channel estimation techniques. Our simulations show that the proposed Bi-LSTM-based DL can flexibly and effectively detect UFMC signals.

Performance evaluation of hybrid transform for universal filtered multi‐carrier system

AbstractHigh peak to average power ratio (PAPR) is viewed as a serious limitation of all multi‐carrier systems. In this article, a companding transform with clipping technique is proposed for universal filtered multi‐carrier (UFMC) system. The proposed companding transform successfully reduces the PAPR by expanding the small amplitude signals and compressing the peak amplitude signals. Moreover, the combination of companding and clipping further reduces the PAPR. Besides, the proposed scheme provides more flexibility by properly selecting companding parameters and clipping ratio (CR). Additionally, this article presents the performance evaluation of various nonlinear companding transforms (NCTs) of the UFMC system in terms of PAPR reduction, bit‐error‐rate, and reduced out‐of‐band emissions. Simulation results confirm that the proposed hybrid transform provides superior system performance when compared to other NCTs. The proposed hybrid transform with CR of 1.4 provides superior PAPR diminution of 8.5 dB and net gain of 8.9 dB when compared to other schemes. Finally, the proposed hybrid transform is validated by using wireless‐open access‐research platform over real time channel.

Maximal-Minimum hybrid approach with decomposed SLM technique for 5G UFMC system PAPR reduction

The Universal Filtered Multi-carrier (UFMC) system's low latency, minimal out-of-band, and low frequency offset support high spectral efficiency and impact 5 G cellular networks. Due to its high peak-to-average power ratio (PAPR), the system's performance is severely degraded. This paper proposes a hybrid Maximal-Minimum approach with decomposed selective mapping to minimize PAPR constraints for 5 G UFMC systems. The complex signal is decomposed into real and imaginary branches, allowing the inverse fast Fourier transform (IFFT) operation. In each branch, different phase vectors are mixed with real and imaginary terms. The FIR response is based on individually optimized PAPR values, which are then copied for transmission. Simulations showed that the proposed method reduced PAPR by optimizing the weighting factor within the Out of Band (OoB) range. It is superior in Bit Error rate (BER)-wise, reduction as compared with selective mapping (SLM) and decomposed-UFMC-SLM.

Spectral Efficiency Improvement Techniques in OFDM and UFMC

Abstract: This article describes about to analyse the spectral efficiency of different modulation techniques in OFDM and UFMC. UFMC is a multi-carrier modulation technique in fifth generation network (5G). In this paper, we review the different modulation techniques in 5G technology and motivate the need of UFMC technique in 5G wireless communication. In 4G OFDM modulation technique, some drawbacks like side band leakages, high Peak to Average Power ratio (PAPR) and spectrum utilization degrades the performance of the system. Another multi carrier technique called Filter Bank Multi carrier (FBMC) which is better than OFDM, have some issues in practical aspects. So by considering the above parameters a move to another technique called Universal Filtered Multi Carrier (UFMC) is used because of good spectrum usage. This paper also explains about the UFMC system model. Based on the Simulation results in MATLAB, the spectrum utilization of UFMC system is much better than OFDM system. Keywords: UFMC, OFDM, 5G, IFFT, FFT, DAC, ADC and Spectrum efficiency.

High-security UFMC optical transmission system of seven-core fiber based on updating the 3D discrete chaotic model.

In this paper, we propose a high-security universal filtered multicarrier (UFMC) transmission system based on a novel, to the best of our knowledge, three-dimensional (3D) discrete chaotic model. The cascade of counters and the 3D discrete chaotic system is used to generate three masking factors and update these factors to encrypt the bitstream, constellation, and the information of the subcarriers. Using this structure, the key space is 10270 and the key is updated in a timely manner. In this work, the encryption scheme solves the dynamic degradation of chaotic cryptography. Experimental results show that there is no significant difference in error performance in comparison with before encryption. Compared with the orthogonal frequency division multiplexing (OFDM) system, the spectrum efficiency of the UFMC system is higher, which reduces out-of-band leakage and interference between services. Considering the complexity constraints of the receiver, the inter-symbol interference caused by fiber dispersion is alleviated by optimizing the distribution of data subbands, and the bit error rate (BER) performance is improved. It is shown that the UFMC system obtains 1.9 dB gain compared with the OFDM system in terms of receiver sensitivity when the BER is 10-3. This encryption scheme has a promising application prospect in short-distance optical access systems in the future.

Deep Learning-Aided Signal Detection for Two-Stage Index Modulated Universal Filtered Multi-Carrier Systems

The growing interests in Internet of Underwater Things (IoUT) put forward more demands for underwater acoustic (UWA) communication technologies. However, the conventional orthogonal frequency division multiplexing (OFDM) technology underperforms in terms of the resistance to carrier frequency offset (CFO), symbol time offset (STO), and applicability to multiple application scenarios. To remedy the deficiencies, this paper introduces the emerging universal filtered multi-carrier (UFMC) technology into UWA communications and devises a two-stage index modulated UFMC (TSIM-UFMC) system for performance improvement. In addition, a deep learning-aided signal detector termed as TSIMNet is proposed for the TSIM-UFMC system over multipath UWA channels. Specifically, at the transmitter, the TSIM-UFMC system adopts two-stage index modulation to characterize the different position information of data, pilot, and inactive subcarriers in each subblock for ameliorating the bit error rate (BER) performance under channel interferences. At the receiver, the TSIMNet detector exploits configurable deep neural networks to encapsulate the index demodulation, channel estimation, and constellation demodulation for optimizing the system structure. Furthermore, TSIMNet can be deployed to detect the received signal online for the TSIM-UFMC system after trained by offline data. Numerical results reveal that the proposed TSIM-UFMC system exhibits achievable advantages in combating CFO and STO, and the TSIMNet detector actualizes a near-optimal performance on BER with preferable computational complexity.

A Joint Time-Domain Channel Estimation with Hybrid PAPR Reduction Scheme in UFMC Systems

In this paper, pilot-based time-domain channel estimation (CE) along with peak-to-average power ratio (PAPR) reduction is proposed for universal filtered multicarrier (UFMC) system. The pilots that are inserted in time domain not only estimate the channel behavior but also can be used in the reduction of PAPR. For PAPR reduction, a linear companding scheme, which can treat amplitudes of the UFMC signal separately with a different scale, is proposed. The proposed companding scheme offers more design flexibility and better performance gains by using two inflexion points. However, the proposed companding scheme requires side information (SI) to perform de-companding at the receiver. The transmission of SI decreases the data efficiency, so a pilot-assisted UFMC system that can perform both data recovery and PAPR reduction without the requirement of SI transmission is proposed. In pilot-assisted UFMC system, the inserted time-domain pilots can enable SI cancellation inherently. Furthermore, a hybrid transform, which improves PAPR performance by employing clipping scheme to the linear companded signal, is proposed. Simulation results confirm that the proposed joint CE with linear companding scheme achieves an improved net gain of 6.5[Formula: see text]dB. Additionally, the proposed hybrid scheme with clipping threshold of 1.4 provides an improved PAPR reduction of 8.8[Formula: see text]dB and enhanced net gain of 7.3[Formula: see text]dB. Moreover, the proposed joint time-domain CE with hybrid PAPR reduction scheme of UFMC system is validated over real time by employing wireless open-access research platform (WARP) board.

Fast Convolution Based Complexity Reduction in Universal Filtered Multi-Carrier Systems

The Universal Filtered Multi-Carrier (UFMC) is a derivative of the Orthogonal Frequency Division Multiplexing (OFDM) scheme. It is considered as a candidate waveform for 5G. The considerably high computational complexity restricts the usage of UFMC based systems. This complexity is caused by the filtration process in the system. Since the flexible and efficient use of non-continuous unused spectrum for different network deployment strategies is important in the next generation communication, the selection of UFMC is inevitable because of its improved performance over OFDM and the Filter Bank Multi-Carrier (FBMC) systems. Hence, it is essential to reduce the complexity of a UFMC system. In this paper, we propose a Fast Convolution (FC) based UFMC system. The technique makes use of smaller FFTs and overlapped data frames. The proposed FC-UFMC system achieves a computation minimisation higher than 95% for systems having 64 or more fully utilised sub-channels compared to similar UFMC systems. The Peak to Average Power Ratio (PAPR) for the FC-UFMC system has a 2.27 dB improvement over the UFMC system. The BER performance of the FC-UFMC system in AWGN and ITU-R channels models are superior or similar to the corresponding UFMC system. The paper also presents the relationship of BER dependence on Signal to Noise Ratio (SNR) and Side Lobe Attenuation (SLA) of the sub-band filter.

Universal Filtered Multicarrier Receiver Complexity Reduction to Orthogonal Frequency Division Multiplexing Receiver

The Universal Filtered Multicarrier (UFMC) waveform technology is one of the promising waveforms for 5G and beyond 5G networks. Owing 2N-point Fast Fourier Transform (FFT) processor at the UFMC receiver, the computational and implementation complexity is two times more than the conventional Orthogonal Frequency Division Multiplexing (OFDM) receiver system. In this paper, we proposed a simplified UFMC receiver structure to reduce computational complexity as well as hardware requirements. The received UFMC symbol simplified exactly to its equivalent after performing 2N-point FFT and decimation operations. In which, the mathematical model of the frequency-domain UFMC signal is rederived after processing through 2N-point FFT and decimator, and the simplified signal is generated with an N-point FFT. Accordingly, the 2N-point FFT processor and decimator are replaced with a single N-point FFT processor. This approach reduces the 50% computational complexity at the FFT processor level hence the hardware and processing time. The computational complexity of the proposed receiver model is approximately equivalent to the OFDM receiver. Additionally, analyzed the mathematical model for the simplified UFMC receiver and the comparative performance of the UFMC system with the conventional model.

A Modified SLM Scheme for PAPR Reduction of UFMC Systems

One of the most promising 5G waveform candidates is the universal-filtered multicarrier system (UFMC). The UFMC system reduces the out-of-band (OoB) emission, bringing about higher spectral efficiency. This is assumed to reach robustness against frequency offset and low latency. Although, as aforementioned, the UFMC system offers many advantages, it lacks high peak-to-average power ratio (PAPR) as a multicarrier transmission technique. This research paper tackles two approaches; firstly, RCS, by developing a simulated conventional SLM system, with modifications to generate the same number of waveforms, while using fewer UFMC modulators. Secondly, by developing a simulated conventional SLM system, with modifications using the same number of modulators to generate more waveforms that would be generated in the conventional scheme. The two sets of results from the proposed M-SLM scheme are compared to each other, and to other PAPR reduction schemes using OFDM and UFMC. To reduce PAPR in UFMC systems, (M-SLM) scheme with low complexity is proposed. The essence of the proposed M-SLM scheme is represented in making use of the cyclically shifting process and FMC modulator’s linearity property. The proposed M-SLM scheme uses Um UFMC modulators to produce Uw alternative UFMC waveforms, where Uw = Um (2Um − 1). As a result, drawing a comparison with existing SLM based PAPR reduction schemes for UFMC systems; the proposed M-SLM scheme's computational complexity is reduced. Finally, there is a comparison between the proposed M-SLM scheme and the schemes there in the literature according to PAPR reduction ability.

A Joint Filter and Spectrum Shifting Architecture for Low Complexity Flexible UFMC in 5G

The hardware realization of Universal Filtered Multi Carrier (UFMC) architecture has attracted significant attention in fifth generation (5G) and beyond. In addition to the flexibility in fast Fourier transform (FFT)-length, a flexible prototype filter in combination with multiplicative complex spectrum shifting co-efficients is required for realizing flexible UFMC architecture. The existing architectures of UFMC transmitter commonly adopted fixed-size FFT-length, number of subbands, subband size, and filter-length. Moreover, the lack of flexible prototype filter and spectrum localization of filter co-efficients to individual subbands limits the flexible UFMC system design. In this paper, we propose VLSI architecture for a flexible length prototype filter that can generate spectrally shifted filter co-efficients to individual subbands in tune with the changing value of FFT-length, number of subbands, subband size, and filter-length. For 16-bit word size architecture, our proposed design produces filter co-efficients and spectrum shifting co-efficients upto length, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2^{15}$ </tex-math></inline-formula> . Thus, any desired combination of FFT-length, number of subbands, subband size and filter-length is selected to generate the filter co-efficients for the individual subbands. Moreover, complex multiplication and addition operations are reduced in proposed architecture, quantitatively, about 58.81% reduction in filtering unit is achieved over the state-of-the-art architecture. Finally, hardware implementation output and XILINX post route simulation result matches perfectly with MATLAB simulations.

A Simulational Performance of 5G MIMO Systems applying UFMC( Universal Filtered Multicarrier) Study

The advanced wireless communication system uses the new technology, preparing the limited radio spectrum and its low expensive resource. The Scenario of Wireless communication is needed for the flexible mechanism with available time and frequency resources.  The OFDM system, which is a multicarrier process with a remote framework in Long Term Evolution (LTE), 4G, and 5G.  Using of UFMC(Universal_Filtered_Multicarrier)system with OFDM system symmetrical recurrence division multiply with modulation system and the correlation between them.  Using of UFMC system with QAM into the MIMO system the result of subchannel, the model channel correlation recreated in “ A Simulational Performance of 5G MIMO Systems applying UFMC (Universal_Filtered_Multicarrier ) Study” result shown in MATLAB.

BCH codes in UFMC: A new contender candidate for 5G communication systems

Nowadays, fifth generation (5G) wireless network is considered one of the most important research topics in wireless industry and it will be substituting with fourth generation (4G) in several aspects. Although the robustness of orthogonal frequency division multiplexing (OFDM) system against channel delays which is the reason behind using it in LTE/LTE Advanced however, it is suffering from high peak to average power ration (PAPR) and out of band side lobes. So, universal filtered multi-carrier (UFMC) technique is considered a new modulation scheme for 5G wireless communication system to overcome on the common OFDM demits. In contrast, to achieve reliable data transmission in digital communication systems, using error correcting codes are considered an essential over noisy channels. In this paper, BCH code has been used for UFMC system over AWGN. The results showed that using BCH codes in UFMC contributed in enhancing BER performance while could decreasing both of PAPR and OOBE values better than conventional OFDM system.

Análisis de la técnica UFMC en un canal multitrayecto y usando estimación de canal

UFMC (Universal Filtered Multi-Carrier) is a novel multi-carrier transmission technique that aims to replace the OFDM (Orthogonal Frequency Division Multiplexing) modulation technique for fifth generation (5G) wireless communication systems. UFMC, being a generalization of OFDM and FBMC (Filter Bank Multicarrier), combines the advantages of these systems and at the same time avoids their main disadvantages. Using a Matlab simulation, this article presents an analysis of the robustness of UFMC against fading effects of multipath channels without using a CP (cyclic prefix). The behavior of the UFMC system is analyzed in terms of the PSD (Power Spectral Density), BER (Bit Error Rate) and MSE (Mean Square Error). The results show that UFMC reduces the out-band side lobes produced in the PSD of the processed signal. Also, it is shown that the pilot-assisted channel estimation method applied in OFDM systems can also be applied in UFMC systems.