scholarly journals A Novel GFDM Waveform Design Based on Cascaded WHT-LWT Transform for the Beyond 5G Wireless Communications

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1831
Author(s):  
Meryem Maraş ◽  
Elif Nur Ayvaz ◽  
Meltem Gömeç ◽  
Asuman Savaşcıhabeş ◽  
Ali Özen

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.

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Qinbiao Yang ◽  
Zulin Wang ◽  
Qin Huang

Orthogonal frequency division multiplexing (OFDM) usually suffers high peak-to-average power ratio (PAPR). As shown in this paper, PAPR becomes even severe for sparse source due to many identical nonzero frequency OFDM symbols. Thus, this paper introduces compressive coded modulation (CCM) in order to restrain PAPR by reducing identical nonzero frequency symbols for sparse source. As a result, the proposed CCM-based OFDM system, together with iterative clipping and filtering, can efficiently restrain the high PAPR for sparse source. Simulation results show that it outperforms about 4 dB over the traditional OFDM system when source sparsity is 0.1.


Author(s):  
Vandana Pundir ◽  
Anwar Ahmad

Orthogonal Frequency Division Multiplexing is a multi-carrier modulation technique which provides numerous advantages like high spectral efficiency, minimal interference, low multipath fading, etc. But Peak-to-average Power Ratio is a severe challenge in using such multiplexing technique as it introduces distortions in nonlinear devices. Various Peak-to-average Power Ratio reduction techniques have been investigated in the literature to improve the performance of Orthogonal Frequency Division Multiplexing systems. But, each of them suffers either from high complexity or degraded bit error rate or less spectral efficiency. For reducing Peak-to-average Power Ratio more effectively, a hybrid combination of Partial Transmit Sequence with Selective Mapping is detected to show better performance. In this paper, we have combined Goppa coding technique with this hybrid Selective Mapping and Partial Transmit Sequence for further improving the performance. Along with Peak-to-average Power Ratio reduction capability, the proposed technique also has inherent error control mechanism due to the use of coding. Based on the simulation results, we have concluded that the proposed technique provides good amount of Peak-to-average Power Ratio reduction than conventional techniques. The proposed technique is analyzed for different number of Orthogonal Frequency Division Multiplexing symbol candidates for Selective Mapping and different number of block divisions for Partial Transmit Sequence. Further, this technique is simulated for different number of subcarriers and modulation order and the simulation results are compared with each other. The proposed technique also shows better Bit error rate values for high Signal-to-Noise ratio.


Author(s):  
Frank Andrés Eras ◽  
Italo Alexander Carreño ◽  
Thomás Borja ◽  
Diego Javier Reinoso ◽  
Luis Urquiza-Aguiar ◽  
...  

Orthogonal Frequency Division Multiplexing (OFDM) is a technique widely used in today's wireless communication systems due to its ability to combat the effects of multi-path in the signal. However, one of the main limitations of the use of OFDM is its high Peak-to-Average Power Ratio (PAPR), which reduces the efficiency of the OFDM system. The effects of PAPR can produce both out-of-band and in-band radiation, which degrades the signal by increasing the bit error rate (BER), this occurs in both baseband and bandpass sginals. In this document the effect of the PAPR in a OFDM passband signal is analyzed considering the implementation of a High Power Amplifier (HPA) and the Simple Amplitude Predistortion-Orthogonal Pilot Sequences (OPS-SAP) scheme to reduce the PAPR.


2010 ◽  
Vol 44 (4) ◽  
pp. 30-41 ◽  
Author(s):  
Guillem Rojo ◽  
Milica Stojanovic

AbstractOrthogonal frequency division multiplexing (OFDM) is an appealing modulation scheme for high-rate underwater acoustic communications that are challenged by multipath propagation. However, it has a drawback in the large peak-to-average power ratio (PAR). Techniques for PAR reduction have been extensively studied for radio communication systems. Although these techniques are applicable to acoustic systems, we take a different approach that aims to capitalize on the fundamental differences between the acoustic and the radio systems; namely, the fact that acoustic transmissions are inherently band limited. We extend the tone reservation technique to the out-of-band carriers and design efficient methods for constructing OFDM signals with lower PAR. Two approaches are investigated, one based on a gradient algorithm and another that uses random sequences. Simulation results show that our techniques can provide PAR reduction without the loss in data rate.


Author(s):  
Shravan Kumar Bandari ◽  
V.V. Mani ◽  
A. Drosopoulos

Purpose – The purpose of this paper is to study the performance of generalized frequency division multiplexing (GFDM) in some frequency selective fading channels. The exact symbol error rate (SER) expressions in Hoyt (Nakagami-q) and Weibull-v fading channels are derived. A GFDM transceiver simulation test bed is provided to validate the obtained analytical expressions. Design/methodology/approach – Modern cellular system demands higher data rates, very low-latency transmissions and sensors with ultra low-power consumption. Current cellular systems of the fourth generation (4G) are not able to meet these emerging demands of future mobile communication systems. To address this requirement, GFDM, a novel multi-carrier modulation technique is proposed to satisfy the future needs of fifth generation technology. GFDM is a block-based transmission method where pulse shaping is applied circularly to individual subcarriers. Unlike traditional orthogonal frequency division multiplexing, GFDM transmits multiple symbols per subcarrier. The authors have used the probability density function approach in solving the final analytical expressions. Findings – Detailed analysis of GFDM performance under Hoyt-q, Weibull-v and Log-Normal Shadowing fading channels. Exact analytical formulae were derived which support the simulations carried out by authors and other authors. The exact dependence of SER on fading parameters and roll-off factor α in the raised cosine pulse shape filter was determined. Practical implications – Development and fabrication of high-performance GFDM systems under fading channel conditions. Originality/value – Theoretical support to simulated system performance.


2021 ◽  
Vol 11 (1) ◽  
pp. 6696-6702
Author(s):  
W. Raza ◽  
X. Ma ◽  
A. Ali ◽  
A. Ali ◽  
A. Raza ◽  
...  

Under-Water Acoustic (UWA) communication networks are commonly formed by associating various independent UWA vehicles and transceivers connected to the bottom of the sea with battery-operated power modems. Orthogonal Frequency Division Multiplexing (OFDM) is one of the most vital innovations for UWA communications, having improved data rates and the ability to transform fading channels into flat fading. Moreover, OFDM is more robust on Inter-Symbol and Inter-Carrier Interferences (ISI and ICI respectively). However, OFDM technology suffers from a high Peak to Average Power Ratio (PAPR), resulting in nonlinear distortions and higher Bit Error Rates (BERs). Saving power of battery deployed modems is an important necessity for sustainable underwater communications. This paper studies PAPR in UWA OFDM communications, employing Selective Mapping (SLM) as a tool to mitigate PAPR. The proposed SLM with the oversampling factor method proves to be less complex and more efficient. Simulation results indicate that SLM is a promising PAPR reduction method for UWA OFDM communications reducing BER.


2018 ◽  
Vol 7 (3.34) ◽  
pp. 487 ◽  
Author(s):  
Kommabatla Mahender ◽  
Tipparti Anil Kumar ◽  
K S Ramesh

This paper describes the aspects of multiple access for emerging (5G) Wireless Communication Systems. Orthogonal Frequency Division Multiplexing (OFDM) is best suited for fourth generation (4G) but it suffers from the problem of high Peak to Average Power Ratio (PAPR) & Side band leakage. Single carrier frequency division multiple access (SC-FDMA) has worked like an alternative to OFDMA only in the uplink process and PAPR was reduced. OFDM based 4G network is not capable of supporting diverse applications and these applications can be implemented by 5G.  High traffic requirements of 5G can be evaluated by using multiple access schemes, namely filter-bank multi-carrier (FBMC), universal-filtered multi-carrier (UFMC), generalized frequency-division multiplexing (GFDM). Comparison of PAPR reduction is done based on Complementary Cumulative Distribution Function (CCDF), for various multiple access 5G waveforms.  


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