Prefix Orthogonal Frequency Division Multiplexing Research Articles

Reduce PAPR in Filtered-CPOFDM using Hybrid Method System

5G multicarrier waveform Filtered Cyclic Prefix Orthogonal Frequency Division Multiplexing (F-CPOFDM) allows for high data speeds and increases in spectrum efficiency. The main drawback of F-CPOFDM is its high peak-to-average power ratio (PAPR), a common element of all multicarrier modulation schemes. In this research is investigate the implementation of a Hybrid strategy to reduce the peak to average power ratio (PAPR) in a F-CPOFDM system and evaluated the impact of employing a Hybrid Technique with Group Codeword Shift (GCS), Median Codeword Shift, Selective Codeword Shift (SCS), and Conventional F-CPOFDM on the reduction of peak to average power ratio (PAPR) in CP-OFDM. The novelty of this research is GCS method integration with WHT Precoding technique for reduce PAPR. Simulation results show that compared to traditional Filtered-CPOFDM, the GCS-WHT method reduces peak PAPR by 59.46 %, while the SCS- method reduces it by 32.43 % and the MCS-WHT method reduces it by 31.53%. Compare to the non-hybrid technique, the GCS only reduce 45.95%, while for SCS and MCS reduce 19.82% and 23.42% respectively. From the results, shows that Hybrid method is better performance compare with non-hybrid method.

PAPR reduction in CP-OFDM (5G) using hybrid technique

The Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) is a 5G multicarrier waveform that offers great data speeds and improvements in spectrum utilisation. The primary CP-OFDM’s weakness is its excessive peak-to-average power ratio (PAPR), which is a characteristic of all multicarrier modulation techniques. We study the application of a hybrid technique approach how to lower the peak to average power ratio (PAPR) in a CP-OFDM system. We also evaluated the outcomes of peak to average power ratio (PAPR) decrease in CP-OFDM, utilising a hybrid technique with Group Codeword Shift (GCS), Median Codeword Shift, Selective Codeword Shift (SCS), and Conventional CP-OFDM. When compared to the non-hybrid technique, the simulation results indicate that the hybrid approach is superior in reducing the peak PAPR by more than 65 percent.

Multi-windowing Technique for 5G and Beyond

Recently, the development of mobile technology has reached a point that requires a high data rate with high waveform aspects. So, traditional ways are no further tolerable. With the dawn of the fifth generation (5G), researchers have been investigating its waveforms and experimenting the methods to improve it. This research examines universal filter multi-carrier (UFMC) for a novel strategy by employing multi-windowing UFMC-based (MW-UFMC) to boost the power spectral density (PSD). This was accomplished by lowering out-of-band emission (OOBE), bit error rate (BER), and adjacent channel leakage ratio (ACLR). The 256quadrature amplitude modulation (256QAM) mapping modulation method was employed in this work. 256QAM is the maximum modulation level that is standard for the third-generation partnership project (3GPP). The proposed MW-UFMC is compared with the conventional UFMC and cyclic prefix orthogonal frequency division multiplexing (CP-OFDM). The proposed multi-windowing technique presents a multistage service that offer a diversity of options to the network operator, which exhibits several advantages over existing methods. These include a lower BER, improved PSD, enhanced spectral efficiency (SE), reduced OOBE that increases capacity for accommodating more bits, decreased ACLR, and lower latency.

Reduce PAPR In Filtered-CPOFDM using Modified SCS Method System

Filtered Cyclic Prefix Orthogonal Frequency Division Multiplexing (F-CPOFDM) is a 5G multicarrier waveform that enables high data rates and spectrum efficiency improvements. The primary drawback of F-CPOFDM is that it has a high peak to average power ratio (PAPR), which is a characteristic of all multicarrier modulation techniques. This paper shows the study of the application on Group Codeword Shift (GCS) approach to reduce the peak to average power ratio (PAPR) in a Filtered- CPOFDM system in this article. Additionally, this paper also compared the results of peak to average power ratio (PAPR) reduction with low complexity in Filtered-CPOFDM using a Group Codeword Shift (GCS) approach, Selective Codeword Shift (SCS), and Conventional CPOFDM. The simulation results indicate that the Group Codeword Shift (GCS) approach reduces peak PAPR by 45.95 percent when compared to conventional Filtered-CPOFDM, 26.13 percent when compared to the Selective Codeword Shift (SCS) method and 22.53 percent when compared to the Median Codeword Shift (MCS) method.

PAPR Reduction in Cyclic Prefix OFDM (5G) System using Group Codeword Shifting Technique

Cyclic Prefix Orthogonal Frequency Division Multiplexing (CPOFDM) is a 5G multicarrier waveform that enables high data rates and spectrum efficiency improvements. The primary drawback of CPOFDM is that it has a high peak to average power ratio (PAPR), which is a characteristic of all multicarrier modulation techniques. We study the application of a Group Codeword Shift (GCS) approach to reduce the peak to average power ratio (PAPR) in a CPOFDM system in this article. Additionally, we compared the results of peak to average power ratio (PAPR) reduction with low complexity in CPOFDM using a Group Codeword Shift (GCS) approach, Selective Codeword Shift (SCS), Median Codeword and Conventional CPOFDM.

Design and Performance Analysis of the Dynamic Reduction of Intrinsic Interference Suppression and BER using QAM-based FBMC for MU-MIMO Communications

The present research work is focused on the study of co-channel interface with its minimization techniques without influencing its performance, in turn, which is desired to achieve the minimized complexity of Quadrature Amplitude Modulation (QAM)-based Filter Bank Multi-Carrier (FBMC) to minimize the interference and increase the spectral features with consideration of intrinsic features extractions for the ML (Maximum Likelihood) synthesis systems. The valid measures are given various concerns under consideration, to start with the consideration of the evaluation of the Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFD performance metrics along with the FBMC/QAM in signal transmission in a dedicated fading channel for the evaluation of the modulation order and BER as a required trade-off for quality assessments. From the results, it can be noted that the proposed FBMC QAM has performed better when compared with conventional FBMC systems. The present research also includes considering and calculating the efficiency of nonlinear channels with the Multi-User Multiple Input Multiple Output (MU-MIMO) and FBMC/QAM techniques. In continuation, the obtained results are dominating significantly to access the possible solution to meet the efficiency of the proposed system. In the next part of the research, it is considered with implementation of the sub-detector during the downlink of the system with the technique of threshold-driven strategy for better accuracy and minimization of the complexity in terms of ML detection in terms of order of its modulation. The calculations of the proposed technique with better BER are done on the recent MATLAB platform with its simulation demonstration for its detailed observation.

A Survey on Physical Layer Techniques and Challenges in Underwater Communication Systems

In the past decades, researchers/scientists have paid attention to the physical layer of underwater communications (UWCs) due to a variety of scientific, military, and civil tasks completed beneath water. This includes numerous activities critical for communication, such as survey and monitoring of oceans, rescue, and response to disasters under the sea. Till the end of the last decade, many review articles addressing the history and survey of UWC have been published which were mostly focused on underwater sensor networks (UWSN), routing protocols, and underwater optical communication (UWOC). This paper provides an overview of underwater acoustic (UWA) physical layer techniques including cyclic prefix orthogonal frequency division multiplexing (CP-OFDM), zero padding orthogonal frequency division multiplexing (ZP-OFDM), time-domain synchronization orthogonal frequency division multiplexing (TDS-OFDM), multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM), generalized frequency division multiplexing (GFDM), unfiltered orthogonal frequency division multiplexing (UF-OFDM), continuous phase modulation orthogonal frequency division multiplexing (CPM-OFDM), filter bank multicarrier (FBMC) modulation, MIMO, spatial modulation technologies (SMTs), and orthogonal frequency division multiplexing index modulation (OFDM-IM). Additionally, this paper provides a comprehensive review of UWA channel modeling problems and challenges, such as transmission loss, propagation delay, signal-to-noise ratio (SNR) and distance, multipath effect, ambient noise effect, delay spread, Doppler effect modeling, Doppler shift estimation. Further, modern technologies of the physical layer of UWC have been discussed. This study also discusses the different modulation technology in terms of spectral efficiency, computational complexity, date rate, bit error rate (BER), and energy efficiency along with their merits and demerits.

Resource scheduling scheme for 5G mmWave CP‐OFDM based wireless networks with delay and power allocation optimizations

AbstractIn this paper, to optimize the average delay and power allocation (PA) for system users, we propose a resource scheduling scheme for wireless networks based on Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP‐OFDM) according to the first fifth‐generation standards. For delay minimization, we solve a throughput maximization problem that considers CP‐OFDM systems with carrier aggregation (CA). Regarding PA, we consider an approach that involves maximizing goodput using an effective signal‐to‐noise ratio. An algorithm for jointly solving delay minimization through computation of required user rates and optimizing the power allocated to users is proposed to compose the resource allocation approach. In wireless network simulations, we consider a scenario with the following capabilities: CA, 256‐Quadrature Amplitude Modulation, millimeter waves above 6 GHz, and a radio frame structure with 120 KHz spacing between the subcarriers. The performance of the proposed resource allocation algorithm is evaluated and compared with those of other algorithms from the literature using computational simulations in terms of various Quality of Service parameters, such as the throughput, delay, fairness index, and loss rate.

Multicarrier Modulation Schemes for 5G Wireless Access

The 5G wireless access technology will supersede its predecessor, 4G, in the current decade, at first coexisting with it and later as a standalone technology. This work examines and compares the performance of the following orthogonal multicarrier schemes: Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM), Windowed Orthogonal Frequency Division Multiplexing (W-OFDM), Filtered Orthogonal Frequency Division Multiplexing (F-OFDM), Universal Filtered Multi-Carrier (UFMC), and Filter Bank Multi-Carrier (FBMC). The system architecture of each scheme is investigated while considering the performance in fading channel models. The simulation was performed using a standard set of parameters, and the performance was appraised based on Power Spectral Density (PSD), Peak to Average Power Ratio (PAPR), Complementary Cumulative Distribution Function (CCDF) of PAPR, Bit Error Rate (BER), and Signal to Noise Ratio (SNR). In addition, a comprehensive analysis is presented concerning filter or window implementation, filtering method, orthogonality, roll-off rate, spectral leakage, spectral efficiency, computational complexity, and runtime complexity. Based on the results, each scheme has its advantages and disadvantages compared with the other methods. FBMC, F-OFDM, and W-OFDM are preferred for better spectrum utilization, transmission accuracy, and power efficiency, respectively. UFMC offers a fine balance between these multicarrier schemes. Therefore, the modulation scheme for the future physical layer will strongly depend on the requirements.

Power and delay optimization based uplink resource allocation for wireless networks with device-to-device communications

In this paper, the resource allocation problem for all devices is investigated in a multi-sharing uplink scenario of mmWave cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM) based wireless networks with device-to-device (D2D) communications. More specifically, a power and delay optimization based uplink resource allocation (PDO-URA) algorithm is proposed divided into two steps. At first, network resources are allocated to cellular user equipments (CUEs) in terms of power and transmission rate through a proposed approach that intends to maximize throughput. Next, idle resources are allocated by considering delay minimization. To this end, we propose to apply an algorithm based on delay optimization where idle resources are shared with D2D user equipments (DUEs) in the network considering the formed conflicts graphs and the delay information estimated through Network Calculus concepts such as envelope process and service curve. Computational simulations are carried out considering a communication scenario with 5G characteristics such as millimeter waves at frequencies above 6 GHz, comparing also the performance of other algorithms from the literature in terms of quality of service (QoS) parameters such as throughput and delay. The results confirm that the proposed algorithm presents superior performance in terms of throughput and delay for the mmWave CP-OFDM wireless networks with D2D communications than the other considered algorithms.

Broadband Channel Based on Polar Codes At 2.3 GHz Frequency for 5G Networks in Digitalization Era

This research using a polar code and without polar codes -based broadband channel that is affected by human blockage using one of the 5G cellular network frequencies at 2.3 GHz, 99 MHz bandwidth, 128 blocks of Fast Fourier Transform (FFT) with Cyclic prefix-Orthogonal Frequency Division Multiplexing ( CP-OFDM) and Binary Shift Keying (BPSK) modulation. The use of high frequencies causes the technology to be sensitive to the surrounding environment and attenuation such as human blockage. The purpose of this research is to determine the performance results and analyze the BER parameters that use polar codes and without polar codes on 5G network broadband channels that are affected by human blockage. Broadband channel modeling on a 5G network is presented in a representative Power Delay Profile (PDP) with the influence of human blockage, which is obtained as many as 41 paths which have multiple delays of 10 ns on each path. This research also uses the scaling method on representative PDP because the use of FFT will produce 128 blocks, and the results of this scaling show that there are 9 lanes with multiple delays of 50 ns. The results of this study are close to the average Bit Error Rate (BER) of 10-4. BER performance without polar code is affected by human blockage requires Signal to Noise (SNR) of 30 dB, for theory BER on BPSK modulation requires SNR of 34.5 dB and BER performance using polar code only requires SNR of 23 dB. These results indicate that using a polar code can reduce or save power usage by 7 dB without a polar codes. Polar codes can minimize errors in the 5G network system, because polar codes are one of the strong codes and are one of the channel coding recommended by ITU to be applied to 5G network systems

Common CP-OFDM Transceiver Design for Low-Complexity Frequency Domain Equalization

Common cyclic prefix-orthogonal frequency-division multiplexing (CCP-OFDM) groups multiple OFDM symbols and uses one CP to protect them in slow time-variant channels. However, due to this particular design of CCP-OFDM systems, complex time-domain estimation algorithms are used to estimate and equalize the channel, such as maximum likelihood (ML) estimators. In this letter, we propose a novel CCP-OFDM transceiver design enabling low-complexity frequency-domain channel estimation and equalization. Simulations under frequency selective channels have validated the effectiveness of the proposed scheme in terms of computational complexity, normalized mean squared error (NMSE), and bit error rate (BER).

Single carrier variable rate scheme and modified carrier allocation over a wireless channel with carrier frequency offset

SummaryCyclic Prefix Orthogonal Frequency Division Multiplexing (CP‐OFDM) is the backbone for the 5G, Internet of Things (IoT), and future generation wireless networks. However, OFDM is less localized in the frequency domain, and that's why more sensitive to carrier frequency offset (CFO). In this paper, different multicarrier variable rate schemes are evaluated in the presence of CFO. Additionally, variable rate schemes based on group orthogonal‐orthogonal frequency division multiple access (GO‐OFDMA) are discussed, and the effect of changing carrier allocation is examined. Different allocation schemes along with different variable rate schemes are verified in the presence of the CFO. Further for Up‐link variable rate application, single‐carrier scenario for the variable rate is proposed in this paper, and bit error rate (BER) performance is evaluated and compared with the variable rate GO‐OFDMA.

Intrinsic interference suppressed FBMC QAM for MU-MIMO systems in computing and communications

PurposeIn order to optimize BER and to substantiate performance measures, initially, the filter bank multicarrier (FBMC) quadrature amplitude modulation (QAM) performance metrics are evaluated with the cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM) system. The efficiency of CP-OFDM, as well as FBMC/QAM that is transmitting over specific fading channels, is evaluated in terms of quality trade-off metrics over bit error rate (BER) as well as modulation order. When compared with the traditional FBMC systems, the proposed FBMC QAM system shows better performance. The performance metrics of FBMC/QAM with the inclusion of multiuser multiple-input-multiple-output (MUMIMO) is validated with worst case channel environment. The performance penalty gap that exists in CP- OFDM is compared with improved FBMC QAM in terms of both BER and OOB radiation measures. The BER trade off comparison between ML and MMSE optimally determine the prominent signal detection model for high performance FBMC QAM system.Design/methodology/approachThe main objective of this research work is to provide perceptions about performance, co-channel interference avoidance as well as about the techniques that are used for minimizing the complexity of the system that is related to FBMC QAM structure for reducing intrinsic interference with higher spectral features as well as maximal likelihood (ML) detector systems.FindingsThis research work also looks at the efficiency of multiuser multiple-input-multiple-output (MU-MIMO) FBMC/QAM over nonlinear channels. Furthermore, when compared with OFDM, it also significantly reduces the penalty gap efficiency, thereby enabling the accessibility of the proposed FBMC QAM system from BER as well as implementation point of view. Finally, the signal detection is facilitated by the sub-detector and is achieved on the downlink side by making use of threshold-driven statistical measures that accurately minimize the complexity trade-off measures of the ML detector over modulation order. The computation of the proposed FBMC method’s BER performance measures was carried out through MATLAB simulation environments, as well as efficiency of the suggested work was demonstrated through detailed analyses.Originality/valueThis research work intend to combine the efficient MU-MIMO based transmission scheme with optimal FBMC/QAM for improved QoS over highly nonlinear channels which includes both delay spread and Doppler effects. And optimal signal detection model is facilitated at the downlink side by making use of threshold-driven statistical measures that accurately minimize the complexity trade-off measures of the ML detector over modulation order. The computation of the proposed FBMC method’s BER performance measures was carried out through MATLAB simulation environments, as well as efficiency of the suggested work was demonstrated through detailed analyses.

Filtered orthogonal frequency division multiplexing for improved 5G systems

Wireless communications became an integrated part of the human life. Fifth generation (5G) is the modern communication which provides enhanced mobile broadband (eMBB), ultra reliable low latency communications (URLLC), and massive machine type communication (mMTC). Thus, 5G have to provide coverage to multi-numerology devices, therefore, modulation and access schemes are suggested in the literature such as cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) and filtered OFDM (f-OFDM). CP-OFDM suffers from the high out of band emission which limited the multi-numerology applications. In f-OFDM, the out of band emission can be suppressed to an accepted extent such that different numerologies can be coexisting. On the other hand, f-OFDM can be more improved by using a proper filtering approach. In this paper three different filters are suggested based windowed-sinc function; Hanning, Hamming, and Blackman. Simulation results show that the proposed filters are promising for high spectral efficiency and out of band emission rejection. Furthermore, the bit error rate, error vector magnitude, and power spectral density are further improved with respect to CP-OFDM scheme but some trade-off is present. Overall, the suggested windowed-sinc filters are outperforming the traditional CP-OFDM. As a conclusion, the suggested windnowed-sinc filters have no limitations on the modulation order or the number of subcarriers utilized in the system.

Spectrally encapsulated OFDM: Vectorized structure with minimal complexity

To efficiently use frequency resources, the next 6th generation mobile communication technology must solve the problem of out-of-band emission (OoBE) of cyclic prefix (CP) orthogonal frequency division multiplexing (OFDM), which is not solved in 5th generation technology. This study describes a new zero insertion technique to replace an existing filtering scheme to solve this internal problem in OFDM signals. In the development of the proposed scheme, a precoder with a two-dimensional structure is first designed by generating a two-dimensional mapper and using the specialty of each matrix. A spectral shaping technique based on zero insertion instead of a long filter is proposed, so it can be applied not only to long OFDM symbols, but also very short ones. The proposed method shows that the transmitted signal is completely blocked at the bandwidth boundaries of signals according to the current standards, and it is confirmed that the proposed scheme is ideal with respect to bit error rate (BER) performance because its BER is the same as that of CP-OFDM. In addition, the proposed scheme can transformed into a real time structure through vectorizing process with minimal complexity.

MMSE-Interference Canceling Receiver for QAM-FBMC Systems

Quadrature amplitude modulation-filter-bank multi-carrier (QAM-FBMC) technology, which utilizes a non-orthogonal pulse-shaping filter, has high spectral confinement characteristics and spectral efficiency, and it is considered as a candidate waveform to replace cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM). However, the QAM-FBMC system suffers from performance degradation due to the non-orthogonal filter no matter how well the prototype filter is designed. In this letter, we propose the interference-canceling algorithm for QAM-FBMC with an MMSE receive filter. The proposed algorithm effectively mitigates the performance degradation caused by the non-orthogonal filters of QAM-FBMC systems, and it closely achieves the performance of CP-OFDM system in moderate SNR region. Also, the proposed algorithm performs the symbol-wise detection, which allows practical implementation without system delay.

Enhanced F-OFDM candidate for 5G applications

The demand for high data rate, the generation of Internet of Things (IoT), and various Machine Type Communications (MTC) emerged for a new transmission phenomenon. In other words, it is substantial to communicate without synchronization, or synchronization overhead, with mixed signal types. such specifications cannot be covered by the Fourth Generation (4G) systems, which is based on Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM). However, to achieve the specifications of the next generation system, numerous waveform replacements for the CP–OFDM were suggested, Filter Bank Multi–Carrier (FBMC), Generalized Frequency Division Multiplexing (GFDM), Universal Filtered Multi–Carrier (UFMC), and Filtered OFDM (F–OFDM). The filter design occupies essential part in these replacements, thus, in this paper, novel filters are introduced where simulation results show that the proposed filters outperform previous designs in terms of spectral efficiency improved dramatically by releasing the synchronization overhead.

Secrecy Capacity of FBMC-OQAM Modulation Over Frequency Selective Channel

This letter studies the information-theoretic secrecy capacity of an Offset-QAM-based filterbank multicarrier (FBMC-OQAM) communication over a wiretap frequency selective channel. The secrecy capacity is formulated as an optimization problem which has a closed-form solution in the high signal-to-noise ratio (SNR) regime. Two of the most common equalization strategies in FBMC-OQAM are considered, namely, single-tap and multi-tap equalization. For the sake of comparison, we also consider the secrecy capacity of a generic modulation and a cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM) modulation. As a result, we find that FBMC-OQAM is particularly competitive for medium-to-long burst transmissions.

Extensionless Adaptive Transmitter and Receiver Windowing of Beyond 5G Frames

Newer cellular communication generations are planned to allow asynchronous transmission of multiple numerologies (waveforms with different parameters) in adjacent bands, creating unavoidable adjacent channel interference. Most prior work on windowing assume additional extensions reserved for windowing, which does not comply with standards. Whether windowing should be applied at the transmitter or the receiver was not questioned. In this work, we propose two independent algorithms that are implemented at the transmitter and receiver, respectively. These algorithms estimate the transmitter and receiver windowing duration of each resource element (RE) with an aim to improve fair proportional network throughput. While doing so, we solely utilize the available extension that was defined in the standard and present standard-compliant algorithms that also do not require any modifications on the counterparts or control signaling. Furthermore, computationally efficient techniques to apply per-RE transmitter and receiver windowing to signals synthesized and analyzed using conventional cyclic prefix orthogonal frequency division multiplexing are derived and their computational complexities are analyzed. The spectrotemporal relations between optimum window durations at either side, as well as functions of the excess signal to noise ratios, the subcarrier spacings and the throughput gains provided over previous similar techniques are numerically verified.