scholarly journals Hybrid Domain Evaluation PTS with Adaptive Selection Methods for PAPR Reduction

2021 ◽  
Author(s):  
Feng Hu ◽  
Yuan Lu ◽  
Libiao JIN ◽  
Jianbo Liu ◽  
Zhiping Xia ◽  
...  
Keyword(s):  
Computational Complexity ◽  
Frequency Domain ◽  
Average Power ◽  
Optimal Solution ◽  
Low Complexity ◽  
Relative Dispersion ◽  
Practical Applications ◽  
Hybrid Domain ◽  
Multicarrier System ◽  
Papr Performance

Abstract Partial transmit sequence (PTS) technique is a fairly suitable scheme to mitigate the high peak-to-average power ratio (PAPR) problem inherent in 5G multicarrier system-especially considering high-order QAM modulation design. However, the high computational complexity level and the speed of the convergence for optimizing the phases of the transmitting signal restricts this technique in practical applications. In this paper, a low-complexity frequency domain evaluated PTS (F-PTS) based on spacing multi-objective (SMO) processing algorithm is proposed to reduce the PAPR values. The PAPR performance are accurately predicted in terms of modifying relative dispersion in the frequency domain. As a result, the complexity of searching the optimal phase factors and IFFT computing is simplified. Moreover, frequency domain and time domain evaluating PTS (FTD-PTS) is employed to search the optimal solution within reasonable complexity. Simulation results verify that the F-PTS scheme can obtain well secondary peaks with lower computational complexity, and the FTD-PTS scheme effectively reduces PAPR with a faster convergence speed.

scholarly journals Low-Complexity Distortionless Techniques for Peak Power Reduction in OFDM Communication Systems

2012 ◽  
Vol 2012 ◽  
pp. 1-13
Author(s):  
A. Ghassemi ◽  
T. A. Gulliver
Keyword(s):  
Computational Complexity ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Low Complexity ◽  
Inverse Discrete Fourier Transform ◽  
Peak Power Reduction ◽  
And Performance ◽  
Selective Mapping ◽  
Papr Performance

A high peak-to-average power ratio (PAPR) is one of the major drawbacks to using orthogonal frequency division multiplexing (OFDM) modulation. The three most effective distortionless techniques for PAPR reduction are partial transmit sequence (PTS), selective mapping (SLM), and tone reservation (TR). However, the high computational complexity due to the inverse discrete Fourier transform (IDFT) is a problem with these approaches. Implementation of these techniques typically employ direct computation of the IDFT, which is not the most efficient solution. In this paper, we consider the development and performance analysis of these distortionless techniques in conjunction with low-complexity IFFT algorithms to reduce the PAPR of the OFDM signal. Recently, proposed IFFT-based techniques are shown to substantially reduce the computational complexity and improve PAPR performance.

scholarly journals Low-Complexity Detection Algorithms for Spatial Modulation MIMO Systems

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Xinhe Zhang ◽  
Yuehua Zhang ◽  
Chang Liu ◽  
Hanzhong Jia
Keyword(s):  
Computational Complexity ◽  
Mimo Systems ◽  
Optimal Solution ◽  
Low Complexity ◽  
Search Tree ◽  
Spatial Modulation ◽  
Algorithm Analysis ◽  
Detection Algorithms ◽  
Search Order ◽  
Ber Performance

In this paper, the authors propose three low-complexity detection schemes for spatial modulation (SM) systems based on the modified beam search (MBS) detection. The MBS detector, which splits the search tree into some subtrees, can reduce the computational complexity by decreasing the nodes retained in each layer. However, the MBS detector does not take into account the effect of subtree search order on computational complexity, and it does not consider the effect of layers search order on the bit-error-rate (BER) performance. The ost-MBS detector starts the search from the subtree where the optimal solution is most likely to be located, which can reduce total searches of nodes in the subsequent subtrees. Thus, it can decrease the computational complexity. When the number of the retained nodes is fixed, which nodes are retained is very important. That is, the different search orders of layers have a direct influence on BER. Based on this, we propose the oy-MBS detector. The ost-oy-MBS detector combines the detection order of ost-MBS and oy-MBS together. The algorithm analysis and experimental results show that the proposed detectors outstrip MBS with respect to the BER performance and the computational complexity.

Factors Influencing the PAPR Performance of OFDM and MIMO-OFDM Systems

2019 ◽  
Vol 11 (3) ◽  
pp. 23-33 ◽  
Author(s):  
Tahreer Mahmood ◽  
Seshadri Mohan
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Average Power ◽  
Channel Fading ◽  
Ofdm Systems ◽  
Practical Applications ◽  
Factors Influencing ◽  
Mimo Ofdm ◽  
Modulation Schemes ◽  
Papr Performance

Multiple-input multiple-output technology together with orthogonal frequency division multiplexing (MIMO-OFDM) is an effective technique to combat multi-channel fading and to improve bandwidth efficiency. Simultaneously, it also increases the system's ability to provide reliable transmission. However, the main disadvantage of OFDM is the high peak-to-average-power ratio (PAPR), which, if not mitigated, will negatively impact practical applications. The high PAPR increases complexity and Bit Error Rate. In this research, the authors investigate the factors influencing the PAPR performance of both OFDM and MIMO-OFDM systems. The objective of this research is to make researchers in this field become familiar with this problem as well as to impart an understanding of the factors that influence PAPR. In this study, the authors classify the factors that impact PAPR into modulation schemes and a number of sub-carriers. These parameters influence the PAPR performance have been analyzed and simulated by using MATLAB. It is observed that the numbers of sub-carriers have a great effect on the PAPR performance. However, modulation schemes can have a small effect on PAPR performance.

scholarly journals A Modified SLM Scheme for PAPR Reduction of UFMC Systems

2021 ◽  
Vol 2128 (1) ◽  
pp. 012004
Author(s):  
Sahar M. Alrabeiy ◽  
Sameh A. Fathy ◽  
Safa M. Gasser ◽  
Mohamed S. El-Mahallawy
Keyword(s):  
Spectral Efficiency ◽  
Average Power ◽  
Low Complexity ◽  
Papr Reduction ◽  
Low Latency ◽  
Power Ratio ◽  
Multicarrier Transmission ◽  
Multicarrier System ◽  
Transmission Technique ◽  
Conventional Scheme

Abstract 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.

scholarly journals A low complexity partial transmit sequence approach based on hybrid segmentation scheme

2020 ◽  
Vol 9 (6) ◽  
pp. 2371-2379
Author(s):  
Ali Hussein Fadel ◽  
Hasanain H. Razzaq ◽  
Salama A. Mostafa
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Low Complexity ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Wave Shape ◽  
Data Sequence ◽  
Practical Applications ◽  
Phase Rotation ◽  
Hybrid Segmentation

The partial transmit sequences (PTS) is regarded as a promising scheme for inhibiting ‎the high peak-to-average power ratio (PAPR) problem in the orthogonal frequency division ‎multiplexing (OFDM) systems. The PTS scheme relies on partitioning the ‎data sequence into subsets and weighting these subsets by a group of the phase rotation ‎factors. Although the PTS can efficiently reduce the high PAPR value, a great ‎computational complexity (CC) level restricts the utilization of the PTS scheme in practical ‎applications. In PTS, there are three common types of segmentation schemes; ‎interleaving (IL-PTS), pseudo-random (PR-PTS), and adjacent (Ad-PTS) schemes. This ‎paper presents a new algorithm named hybrid pseudo-random and interleaving cosine wave shape ‎‎(H-PRC-PTS) by combining the PR-PTS scheme and the symmetrical ‎interleaving cosine wave shape (S-IL-C-PTS) scheme which was proposed in our previous ‎work. The results indicate that the suggested algorithms can ‎diminish the PAPR value like the PR-PTS scheme, whereas the CC level is reduced significantly.

scholarly journals PAPR Performance Analysis of low Complexity SLM for Various Phase Sequences in MIMO-OFDM System

2019 ◽  
Vol 8 (2) ◽  
pp. 4347-4353
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Multipath Fading ◽  
Low Complexity ◽  
Superior Performance ◽  
Ofdm Systems ◽  
Phase Sequence ◽  
Mimo Ofdm ◽  
Papr Performance

Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing (MIMO OFDM) is a key technology for contemporary communication systems due to its spectral efficiency, higher data rates, better diversity gain, good link reliability and both inter symbol interference (ISI) and multipath fading free transmission. However, due to the presence of OFDM, MIMO-OFDM suffers from high peak to average power ratio (PAPR). Even though, several schemes are available to mitigate PAPR, there is no standard solution. Selective Mapping (SLM) significantly reduces the PAPR in OFDM systems at the cost of computational complexity (CC). The CC of SLM can be reduced by proper design of SLM. This paper considers a low complexity SLM (LC SLM) scheme in which both the CC and length of the index of selected phase sequence are significantly reduced. The PAPR of an SLM-OFDM depends on the number of subcarriers in OFDM, the number of candidate blocks in SLM and selected phase sequence and this paper investigate various phase sequences and analyses their PAPR performance. Simulation results show the superior performance of Riemann sequence over the other phase sequences.

Multiuser Diversity OFDMA using Power Priority Selection and Adaptive Clipping

2014 ◽  
Vol 5 (4) ◽  
pp. 18-30
Author(s):  
Akihiro Kuroha ◽  
Chang-Jun Ahn ◽  
Tatsuya Omori ◽  
Ken-ya Hashimoto
Keyword(s):  
Performance Improvement ◽  
Multiple Access ◽  
Average Power ◽  
Low Complexity ◽  
Multiuser Diversity ◽  
Frequency Division ◽  
Peak Reduction ◽  
Sum Capacity ◽  
And Performance ◽  
Papr Performance

In recent, orthogonal frequency division multiple access (OFDMA) has been used for a multiuser wireless communication. In a wireless network, the transmitted signal of each user has independent channel fluctuation characteristic. By using this characteristic, OFDMA can achieve the multiuser diversity (MUDiv). Until this time, to achieve a low complexity and performance improvement, the adaptive subcarrier block (ASB) and frequency symbol spreading (FSS) methods have been proposed. However, the system performance in a low Eb/N0 is worse than that of maximal sum capacity (MSC) and peak to average power ratio (PAPR) does not decrease greatly. To solve these problems, in this paper, we propose the subcarrier allocation with the power priority selection (PSS) and the adaptive clipping (AC) with the peak reduction signal to improve the system and PAPR performance.

scholarly journals Median codeword Shift (MCS) technique for PAPR reduction with low complexity in OFDM system

2019 ◽  
Vol 9 (6) ◽  
pp. 4882
Author(s):  
Mohd Danial Rozaini ◽  
Azlina Idris ◽  
Darmawaty Mohd Ali ◽  
Ezmin Abdullah
Keyword(s):  
Computational Complexity ◽  
Communication Technology ◽  
Orthogonal Frequency Division Multiplexing ◽  
Rapid Development ◽  
Average Power ◽  
Low Complexity ◽  
Papr Reduction ◽  
Frequency Division ◽  
High Data ◽  
Data Rates

With the rapid development of today’s communication technology, the need for a system capable to improve spectral efficiency, high data rates and at the same time can reduce inter-symbol interference (ISI) is necessary. Orthogonal Frequency Division Multiplexing (OFDM) meet all the requirements needed. However, the high peak to average power ratio (PAPR) has become its major obstacle. This paper is focusing on the development of Median Codeword Shift (MCS), which a new PAPR reduction technique with the capability to reduce the computational complexity of the system. This can be achieved through codeword structure alterization and bit position manipulation by utilizing the circulant shift process. The simulation results revealed that the proposed technique overwhelm conventional OFDM and SCS with 24% improvement and 0.5 dB gap from SCS. In fact, the proposed technique possess a lower computational complexity by reducing 16.67% of the use of IFFT block in the system in contrast with SCS technique.

scholarly journals Low Complexity Rotation Algorithm for Reducing PAPR in Partial Transmits Sequence

2021 ◽  
Author(s):  
Thamer Alameri ◽  
Nabeel ali ◽  
Mothana Attiah ◽  
Mohammed Saad Talib ◽  
Jawad Mezaal
Keyword(s):  
Computational Complexity ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Low Complexity ◽  
Papr Reduction ◽  
Frequency Division Multiplexing ◽  
Power Ratio ◽  
Frequency Division ◽  
Complexity Level ◽  
Novel Approach

Abstract High peak to average power ratio (PAPR) is considered as a prime challenge in orthogonal frequency division multiplexing. The partial transmits sequence (PTS) technique is one of the most effective methods for restraining the PAPR pattern. This study proposes a novel approach for enhancing PAPR reduction performance in a PTS by partitioning each subblock into two parts then exchanging the first sample with the last selection in each part of the subblock to generate a new partitioning scheme. The proposed algorithm is analysed and applied to typical traditional segmentation schemes, namely, the adjacent, interleaving and pseudo-random schemes. Moreover, simulation is conducted with two scenarios in which the number of subcarriers is set to 128 and 256. In both systems, the improved segmentation schemes demonstrate PAPR reduction performance that is superior to that of the traditional strategies. Furthermore, the computational complexity level of the enhanced adjusted PTS scheme is low compared with that of the conventional schemes.

Capacity Analysis for Correlated Multi-Hop MIMO Channels under Colored Noise

2015 ◽  
Vol 1 ◽  
pp. 41
Author(s):  
Nguyen N. Tran ◽  
Ha X. Nguyen
Keyword(s):  
Computational Complexity ◽  
Mutual Information ◽  
Closed Form Solution ◽  
Optimal Solution ◽  
Form Solution ◽  
Maximization Problem ◽  
Capacity Analysis ◽  
Mimo Channels ◽  
Average Mutual Information ◽  
Channel Output

A capacity analysis for generally correlated wireless multi-hop multi-input multi-output (MIMO) channels is presented in this paper. The channel at each hop is spatially correlated, the source symbols are mutually correlated, and the additive Gaussian noises are colored. First, by invoking Karush-Kuhn-Tucker condition for the optimality of convex programming, we derive the optimal source symbol covariance for the maximum mutual information between the channel input and the channel output when having the full knowledge of channel at the transmitter. Secondly, we formulate the average mutual information maximization problem when having only the channel statistics at the transmitter. Since this problem is almost impossible to be solved analytically, the numerical interior-point-method is employed to obtain the optimal solution. Furthermore, to reduce the computational complexity, an asymptotic closed-form solution is derived by maximizing an upper bound of the objective function. Simulation results show that the average mutual information obtained by the asymptotic design is very closed to that obtained by the optimal design, while saving a huge computational complexity.

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