DHT-based GFDM and STC-GFDM systems for beyond 5G wireless networks

Generalized frequency division multiplexing (GFDM) is a recent physical layer scheme proposed for next-generation cellular systems. Like orthogonal frequency division multiplexing (OFDM), it is based on multicarrier modulation, but the filter shape is no longer rectangular (roll off &#x2260; 0) and the orthogonality between subcarriers is lost. With higher flexibility, low peak to average power ratio (PAPR) and reduced out-of-band emissions compared with OFDM, GFDM modulation is an attractive candidate for 5G application scenarios. This paper explores the performance of 10 Gb&#x002F;s GFDM system over the optical link in terms of PAPR, quality factor (<italic>Q</italic> factor), and mean squared error using a third-order adaptive Volterra filter with 3 and 5 taps. The impact of linear impairments (chromatic dispersion, polarization mode dispersion), laser line width, and Mach&#x2013;Zehnder non-linearity have been addressed. The results of our simulations indicate that the transmitted 10 Gb&#x002F;s GFDM signal through an optical fiber can reach 930 Km and <italic>Q</italic> &#x003D; 11.9 dB after 700 Km at &#x2013;8 dBm of launch power using 5 taps third-order adaptive Volterra equalizer with an improvement of approximately 210 Km and 1.25 dB compared with the same equalizer with 3 taps.

Generalized Frequency Division Multiplexing (GFDM) is a non-orthogonal multicarrier transmission scheme proposed for fifth (5G) and future generation wireless networks. Due to its attractive properties, it has been recently discussed as a candidate waveform for the future wireless communication systems. GFDM is introduced as a generalized form of the widely used Orthogonal Frequency Division Multiplexing (OFDM) modulation scheme and it uses only one cyclic prefix (CP) for a group of symbols. The main focus of this work is to present like impact on the system performance the coefficient quantity of the subcarrier filter. A simple method for the computation of the coefficients of the prototype filter is employed. Besides, it is presented a structure for the GFDM by taking advantage of the arrangement in the modulation matrix. We evaluated the Bit Error Rate (BER) using the receiver models presented in this work. The results showed that the BER is affected according to the coefficients quantity of the prototype filter. Based on the obtained results, the coefficients quantity has a relation with the number of time slots of the GFDM system.

Generalized frequency division multiplexing (GFDM) and circular filter bank multicarrier (C-FBMC) are two contender waveforms with circular pulse-shaping that are recently proposed for the physical layer of the fifth generation of wireless communication networks (5G). This paper puts these waveforms under the microscope and conducts an analysis on their practical feasibility and performance. In addition, we present a transmitter structure for both GFDM and C-FBMC and show that this structure has the same complexity for both systems. In this paper, GFDM receiver with successive interference cancellation (SIC) is considered as it can get a performance close to that of OFDM (orthogonal frequency division multiplexing). Our bit error rate (BER) performance analysis reveals that GFDM has limitations in terms of the total number of symbols per data packet. When the number of symbols in a packet has an even value, GFDM suffers from a high error floor in BER. For the small constellation sizes, GFDM and C-FBMC reach the same BER performance as that of OFDM. As the constellation size increases, a gap between the BER curve of GFDM and OFDM starts to appear while C-FBMC keeps the same performance as OFDM. Finally, our computational complexity analysis reveals that C-FBMC receiver is simpler than GFDM.

This paper proposes a new scheme to mitigate the effects of interference in generalized frequency division multiplexing (GFDM) systems. We take advantage of the tabu search (TS) process that was originally designed to find approximate solutions for combinatorial optimization problems. We find the initial solution through the application of conventional GFDM receivers such as matched filter and zero-forcing receivers. Starting from the initial solution, we apply the TS algorithm to find a new solution that has lower cost in terms of maximum likelihood costs. In this way, the proposed system can alleviate the interference inherent in GFDM systems. Simulation results show that the proposed system outperforms conventional GFDM systems and orthogonal frequency division multiplexing (OFDM) systems in a multi-path channel regardless of the roll-off factor of the prototype filter.

PAPR analysis of wavelet based multitaper GFDM system

Generalised frequency division multiplexing (GFDM) is a multicarrier transmission scheme that offers a flexible framework to address diverse requirements of fifth generation of cellular networks. Compared to orthogonal frequency division multiplexing (OFDM), the application of pulse shaping in GFDM can control the out of band (OOB) radiation and enables relaxed synchronisation requirements. However, the sub-carriers in GFDM are no longer orthogonal and there is inherent interference. Since this interference is known at the transmitter, it can be mitigated by means of precoding techniques. In this paper, Tomlinson-Harashima precoding (THP) scheme is applied to GFDM transceiver and its performances is compared to previous methods in terms of bit error rate (BER) and peak to average power ratio (PAPR). The results show that the proposed precoder outperforms previous methods in both BER and PAPR.

This article addresses linear precoder design for the peak‐to‐average power ratio (PAPR) reduction of the generalized frequency division multiplexing (GFDM) scheme. This design relies on minimizing various statistical parameters of the instantaneous power of the GFDM signal—including variance, second and third moments—using gradient‐based optimization methods. In this regard, a general framework of four different scenarios, which employs the steepest descent and conjugate‐gradient methods and utilizes two different approaches of fixed and dynamic step‐sizing, is proposed. In the case of fixed step‐sizing, the results demonstrate that the algorithm diverges in some scenarios and provides low‐speed convergence for the others due to its inability in meeting the terminating threshold regarding minimizing objective function to a desirable level. However, dynamic step‐sizing using the Wolf line search rule circumvents these drawbacks, outperforms the existing research, and converges in all scenarios to a precoder providing advantages in terms of design speed and achievable PAPR, while keeping the symbol error rate and out‐of‐band emissions at the ranges of the un‐precoded GFDM systems. Moreover, the results confirm the comprehensiveness of the proposed framework in adapting to various GFDM statistical parameters and gradient methods.

Generalized Frequency Division Multiplexing (GFDM) is a flexible multi-carrier transmission to overcome the disadvantages of OFDM. The weakness of GFDM, similarly to the other multicarrier signals, is a high PAPR, large PAPR signals can easily saturate the transmit power amplifier and cause degradation in Symbol Error Rate (SER) performance and Out-of-Band (OOB) emissions. In this paper, we analyze the effects of Non-Linear distortion using the Saleh model in GFDM. We investigate three parameters: CCDF of PAPR, frequency spectrum, and SER. The simulation results show that GFDM superior to OFDM in PAPR performance and spectrum if given the non-linear distortion. But non-linear distortion in GFDM cause SER performance is decreasing significantly while GFDM is less affected by linearity than OFDM.

Generalized frequency division multiplexing (GFDM) and circular filter bank multicarrier (C-FBMC) are two contender waveforms with circular pulse-shaping that are recently proposed for the physical layer of the fifth generation of wireless communication networks (5G). This paper puts these waveforms under the microscope and conducts an analysis on their practical feasibility and performance. In addition, we present a transmitter structure for both GFDM and C-FBMC and show that this structure has the same complexity for both systems. In this paper, GFDM receiver with successive interference cancellation (SIC) is considered as it can get a performance close to that of OFDM (orthogonal frequency division multiplexing). Our bit error rate (BER) performance analysis reveals that GFDM has limitations in terms of the total number of symbols per data packet. When the number of symbols in a packet has an even value, GFDM suffers from a high error floor in BER. For the small constellation sizes, GFDM and C-FBMC reach the same BER performance as that of OFDM. As the constellation size increases, a gap between the BER curve of GFDM and OFDM starts to appear while C-FBMC keeps the same performance as OFDM. Finally, our computational complexity analysis reveals that C-FBMC receiver is simpler than GFDM.

Optimal prototype filter design in GFDM systems for self-interference elimination: A novel signal processing approach

Generalized frequency division multiplexing (GFDM) system with maximal ratio transmission (MRT) scheme is considered to analyse the symbol error rate (SER) performance over - fading channel.In present days, low latency and low consumption of energy devices are used and these can be achieved using multicarrier techniques.The GFDM is one such multicarrier technique which has a capable to provide these requirements.Low out-of-band (OOB) radiation is one of the GFDM technique's main benefits.Initially, in this study, GFDM-MRT system is used to investigate the SER expression analysis in - fading.Initially, we have addressed the closed form of novel mathematical analysis of SER expression under - fading channel.The Rayleigh, Nakagami-m, and Nakagami-q fading channels are all special instances in the suggested derivation.Later, a Monte-Carlo simulation-based test-bed is developed in MATLAB software and simulations are evaluated for various values of fading parameters, different roll-off factors, and the number of transmitting antennas Nt.The GFDM-MRT technology provides lower SER values and it is more dependable for highspeed communications, it can be inferred.The main object of this paper is to compare the SER of GFDM-MRT system with GFDM system without using MRT technique in - fading channel for different comparing parameters like at number of transmitting antennas Nt , different values of roll-off factors () and fading parameters and

In this paper, a new WHT-LWT-GFDM waveform obtained by combining Walsh–Hadamard Transform (WHT), Lifting Wavelet Transform (LWT), and Generalized Frequency Division Multiplexing (GFDM) is presented for use in next-generation wireless communication systems. The proposed approach meets the requirement of 5th-generation (5G) and beyond communication schemes in terms of low latency, low peak-to-average-power ratio (PAPR), and low bit-error rate (BER). To verify the performance of the presented waveform, PAPR and BER simulation results were obtained in additive white Gaussian noise (AWGN) and flat Rayleigh fading channels, and the performance of the proposed system was compared with conventional Orthogonal Frequency Division Multiplexing (OFDM), GFDM, and Walsh–Hadamard transform-based GFDM (WHT-GFDM). Simulation results show that the proposed waveform achieves the best BER and PAPR performances and it provides considerable performance gains over the conventional waveforms.

Generalized frequency division multiplexing (GFDM) is considered a nonorthogonal waveform and can cause difficulties when used in the spatial multiplexing mode of a multiple-input-multiple-output (MIMO) scenario. In this paper, a class of GFDM prototype filters, in which the GFDM system is free from inter subcarrier interference, is investigated, enabling frequency-domain decoupling during processing at the GFDM receiver. An efficient MIMO-GFDM detection method based on depth-first sphere decoding is subsequently proposed with this class of filters. Numerical results confirm a significant reduction in complexity, especially when the number of subcarriers is large, compared with existing methods.

Generalized Frequency Division Multiplexing (GFDM) is a recently proposed multicarrier waveform which is being considered as one of the possible candidates for 5G wireless access technology. Key advantages of GFDM are flexibility and low spectral side-lobes which render it the ability of carrier aggregation and reduced adjacent channel interference. However due to its non-orthogonal nature GFDM suffers from the problem of self-inter-carrier interference (self-ICI) which occurs between time-slots of adjacent subcarriers in the signal. Due to self-ICI, the bit-error rate (BER) performance of GFDM is severely affected under low SNR regime. Moreover application of MIMO technique to GFDM further adversely affects the BER due to inter-antenna interference (IAI) between the transmit antennas. To mitigate this problem, spatial modulation has been applied to GFDM and its BER performance with respect to V-BLAST based GFDM is studied under flat Rayleigh fading channel condition through computer simulations.

Orthogonal Frequency Division Multiplexing (OFDM) is employed in the current 4G cellular technologies. Because of its resistance to multipath propagation channels, OFDM is a popular multicarrier modulation technique. Although OFDM is one of the effective approaches for a 4G network, out-of-band radiation, inter-symbol interference (ISI), and inter-carrier interference make this method unsuitable for 5G. (ICI). A new approach or next-generation cellular network, i.e., very high data rate, low latency, greater throughput, more device connectivity, and improved device-to-device communication, should be used to deliver effective and dependable communication. The system introduces generalized frequency division multiplexing (GFDM). In GFDM, a single cyclic prefix is utilized throughout the frame and an adjustable pulse-shaping filter can be used to monitor the transmitted signal’s out-of-band emission. Using this ISI, the multipath channel can be controlled. In the proposed system, with large signal constellations, higher-order modulation schemes, and advanced receiver structure, a very high data rate can be achieved. By using various iterative receiver structures the performance of the GFDM system in 5G cellular networks can be analyzed.