Resource Allocation-Based PAPR Analysis in Uplink SCMA-OFDM Systems

Rajasekaran, Aditya S.; Vameghestahbanati, Monirosharieh; Farsi, Mohammad; Yanıkömeroğlu, Halim; Saeedi, Hamid

doi:10.1109/access.2019.2952071

Cited by 28 publications

(14 citation statements)

References 39 publications

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“…The complementary cumulative distribution function (CCDF) is adopted to evaluate the PAPR performance of the OTFS-BFDM signal. The CCDF can be expressed by calculating the probability that the PAPR value of each sample exceeds the predefined threshold

as follows [ 24 ]:

…”

Section: Otfs-bfdm Systemmentioning

confidence: 99%

“…It is worth noting that for PAPR reduction in multi-carrier systems using message-passing (MP) decoding, the sparsity of the ECM must be maintained [ 23 ]. In [ 24 ], Rajasekaran et al proposed an SLM method based on a resource allocation strategy to suppress the PAPR of sparse code multiple access-based OFDM (SCMA-OFDM), but extra sideband information must be transmitted. In [ 25 ], Gao and Zheng adjusted the clipping filter coefficient to achieve a good tradeoff between the PAPR and BER performance of the pilot-embedded OTFS system.…”

Section: Introductionmentioning

confidence: 99%

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A Message Passing-Assisted Iterative Noise Cancellation Method for Clipped OTFS-BFDM Systems

Bie

Wen

2022

Sensors

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Compared with orthogonal frequency division multiplexing (OFDM) systems, orthogonal time frequency space systems based on bi-orthogonal frequency division multiplexing (OTFS-BFDM) have lower out-of-band emission (OOBE) and better robustness to high-mobility scenarios, but suffer from a higher peak-to-average ratio (PAPR) in large data packets. In this paper, one-iteration clipping and filtering (OCF) is adopted to reduce the PAPR of OTFS-BFDM signals. However, the extra noise introduced by the clipping process, i.e., clipping noise, will distort the desired signal and increase the bit error rate (BER). We propose a message passing (MP)-assisted iterative cancellation (MP-AIC) method to cancel the clipping noise based on the traditional MP decoding at the receiver, which incorporates with the (OCF) at the transmitter to keep the sparsity of the effective channel matrix. The main idea of MP-AIC is to extract the residual signal fed to the MP detector by iteratively constructing reference clipping noise at the receiver. During each iteration, the variance of residual signal and channel noise are taken as input parameters of MP decoding to improve the BER. Moreover, the convergence probability of the modulation alphabet after MP decoding in the current iteration is used as the initial probability of MP decoding in the next iteration to accelerate the convergence rate of MP decoding. Simulation results show that the proposed MP-AIC method significantly improves MP-decoding accuracy while accelerating the BER convergence in the clipped OTFS-BFDM system. In the clipped OTFS-BFDM system with rectangular pulse shaping, the BER of MP-AIC with two iterations can be reduced by 72% more than that without clipping noise cancellation.

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as follows [ 24 ]:

…”

Section: Otfs-bfdm Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Message Passing-Assisted Iterative Noise Cancellation Method for Clipped OTFS-BFDM Systems

Bie

Wen

2022

Sensors

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“…It should be noted that this orthogonality is different from the multiple access schemes which may or may not be orthogonal as seen in orthogonal multiple access (OMA), and non-orthogonal multiple access (NOMA) schemes [4]. Although the orthogonality in multiple access scheme has also increment effect on peak to average power ratio (PAPR) for multiple users [5], in this paper only the PAPR of one user signal waveform is analysed. As, Fourier transform [6,7] plays an essential role in developing OFDM signals, it is fundamental to understand the connection of Fourier transform and creation of high peaks in any multi-carrier signal which has been used in many telecommunication systems [4].…”

Section: Introductionmentioning

confidence: 98%

Performance Investigation of Peak Shrinking and Interpolating the PAPR Reduction Technique for LTE-Advance and 5G Signals

et al. 2019

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Orthogonal frequency division multiplexing (OFDM) has become an indispensable part of waveform generation in wideband digital communication since its first appearance in digital audio broadcasting (DAB) in Europe in 1980s, and it is indeed in use. As has been seen, the OFDM based waveforms work well with time division duplex operation in new radio (NR) systems in 5G systems, supporting delay-sensitive applications, high spectral efficiency, massive multiple input multiple output (MIMO) compatibility, and ever-larger bandwidth signals, which has demonstrated successful commercial implementation for 5G downlinks and uplinks up to 256-QAM modulation schemes. However, the OFDM waveforms suffer from high peak to average power ratio (PAPR), which is not desired by system designers as they want RF power amplifiers (PAs) to operate with high efficiency. Although NR offers some options for maintaining the efficiency and spectral demand, such as cyclic prefix based (CP-OFDM), and discrete Fourier transform spread based (DFT-S-OFDM) schemes, which have limiting effects on PAPR, the PAPR is still as high as 13 dB. This value increases when the bandwidth is increased. Moreover, in LTE-Advance and 5G systems, in order to increase the bandwidth, and data-rate, carrier aggregation technology is used which increases the PAPR the same way that bandwidth increment does; therefore, it is essential to employ PAPR reduction in signal processing stage before passing the signal to PA. In this paper, we investigate the performance of an innovative peak shrinking and interpolation (PSI) technique for reducing peak to average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) based signals at waveform generation stage. The main idea behind the PSI technique is to extract high peaks, scale them down, and interpolate them back into the signal. It is shown that PSI technique is a possible candidate for reducing PAPR without compromising on computational complexity, compatible for existing and future telecommunication systems such as 4G, 5G, and beyond. In this paper, the PSI technique is tested with variety of signals in terms of inverse fast Fourier transform (IFFT) length, type of the signal modulation, and applications. Additional work has been carried out to compare the proposed technique with other promising PAPR reduction techniques. This paper further validates the PSI technique through experimental measurement with a power amplifier (PA) test bench and achieves an adjacent channel power ratio (ACPR) of less than -55 dBc. Results showed improvement in output power of PA versus given input power, and furthermore, the error vector magnitude (EVM) of less than 1% was achieved when comparing of the signal after and before modification by the PSI technique.

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“…Applying PAPR reduction techniques that scale in complexity with the number of subcarriers becomes challenging in such an environment. Furthermore, with novel multiple access solutions, e.g., non- orthogonal multiple access (NOMA), that run over OFDM being studied for B5G systems, these tradeoffs in the PAPR solutions between PAPR reduction, complexity and BER loss are an important research topic [4].…”

Section: Introductionmentioning

confidence: 99%

A Hybrid Companding and Clipping Scheme for PAPR Reduction in OFDM Systems

et al. 2021

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Orthogonal frequency division multiplexing (OFDM) continues to be deployed in 5G communication systems and is likely to be used in beyond 5G (B5G) communication systems as well, due to its many advantages. However, one major drawback with OFDM systems is its high peak-to-average power ratio (PAPR), especially with large bandwidth transmissions. In this paper, we have provided a regularization optimization based flexible hybrid companding and clipping scheme (ROFHCC) used for PAPR reduction in OFDM systems. To reduce the design complexity, the companding function has two parts. It restrains the signal samples with amplitudes over a given value to a constant value for both peak power reduction and small power compensation. For signals with samples less than a given amplitude, they are expanded by a linear companding function. We build a regularization optimization model to jointly optimize the companding distortion as well as the continuity of the companding function for bit error rate (BER) performance as well as power spectral density (PSD) performance. Simulation results indicate that for the same PAPR performance, the proposed companding scheme has an advantage over the referenced companding schemes. For example, when the average signal power is normalized to be 1, we choose both PAPR for ROFHCC scheme and two-piecewise companding (TPWC) scheme as 4 dB, then we can find that at BER = 10 −4 , the minimum required E b /N 0 for ROFHCC scheme is around 2.3 dB lower than TPWC scheme.

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Resource Allocation-Based PAPR Analysis in Uplink SCMA-OFDM Systems

Cited by 28 publications

References 39 publications

A Message Passing-Assisted Iterative Noise Cancellation Method for Clipped OTFS-BFDM Systems

A Message Passing-Assisted Iterative Noise Cancellation Method for Clipped OTFS-BFDM Systems

Performance Investigation of Peak Shrinking and Interpolating the PAPR Reduction Technique for LTE-Advance and 5G Signals

A Hybrid Companding and Clipping Scheme for PAPR Reduction in OFDM Systems

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