AGP–NCS Scheme for PAPR Reduction
Amit ᭄᭄ Mishra2015, Wireless Personal Communications
Sign up for access to the world's latest research
checkGet notified about relevant papers
checkSave papers to use in your research
checkJoin the discussion with peers
checkTrack your impact
Abstract
In this paper, a combinational method is proposed for peak-to-average power ratio reduction in orthogonal frequency division multiplexing systems using approximate gradientproject with null-subcarriers switching (AGP-NCS) scheme. The key idea of the proposed method is to generate a dynamically extended outer constellation points using AGP method with exploiting the concept of NCS process. The proposed method substantially reduces peakto-average power without sacrificing the bit error rate. Moreover, proposed scheme requires no channel side information during transmission, therefore shows no reduction in data rate. The simulation results of proposed method show a better performance when compared with other methods.
Related papers
Partial approximate gradient constellation for PAPR reduction in OFDM signals
International Journal of Systems, Control and Communications, 2016
In this paper, a combinational approach for peak-to-average power ratio reduction in orthogonal frequency division multiplexing is proposed. The key idea of the proposed scheme is to apply partial transmit sequence and approximate gradient project schemes in parallel on two equal halves of subcarrier in an OFDM standard. On one half, partial transmit sequence minimises the PAPR of OFDM symbols through disjoint sub blocks and optimised phase factors, whereas for the other half, approximate gradient project extends the outer constellation points of OFDM symbols dynamically within margin-preserving constraints to reduce the peak magnitude of symbols. The simulation results show that proposed schemes reduces the PAPR as compared to other conventional schemes and maintains the bit error rate performance of the system especially at low signal to noise ratio. Moreover, the proposed method improves the data rate and also reduces the computational complexity when compared with partial transmit sequence scheme.
IJRECE:: PAPR Reduction in OFDM Using Computationally Efficient Null-Data Subcarriers Switching Algorithm
To reduce the computational complexity, an algorithm is proposed which is used with existing null-data subcarrier switching method of OFDM. PAPR is main drawback of OFDM. So it is necessary to reduce it. Many techniques were developed to reduce the PAPR but they required more time to reduce it. Here in this method Peak to Average Power Ratio (PAPR) is also reduced and also this method achieves significant reduction in computational overhead without sacrificing PAPR reduction capability of original method. This algorithm can be use with other existing algorithms to reduce the computational overhead further. This proposed algorithm is very useful in services where time is an important factor than accuracy. The effectiveness of the proposed algorithm is demonstrated by presenting results
PAPR Reduction in Wireless OFDM Systems
Non-linear programming has been extensively used in wireless telecommunication systems design. PAPR reduction is implemented in the handheld devices and low complexity is a major objective. High PAPR is one of the major disadvantages of OFDM system which is resulted from large envelope fluctuation of the signal. Our proposed technique to reduce the PAPR is based on constellation shaping that starts with a larger constellation of points, and then the points with higher energy are removed. The constellation shaping algorithm is combined with peak reduction, with extra abilities defined to reduce the signal peak. This method, called MMSE-Threshold, has a significant improvement in PAPR reduction with low computational complexity. The peak reduction formulated into a quadratic minimization problem is subsequently optimized by the semi-definite programming algorithm, and the simulation results show that the PAPR of semi-definite programming algorithm (SDPA) has noticeable improvement over MMSE-Threshold while SDPA has higher complexity. Results are also presented for the PAPR minimization by applying optimization techniques such as hill climbing and simulated annealing. The simulation results indicate that for a small number of subcarriers, both hill climbing and simulated annealing result in a significant improvement in PAPR reduction, while their degree of complexity can be very large.
PAPR Reduction of OFDM Signals using Active Constellation Extension and Tone Reservation Hybrid Scheme
The Orthogonal Frequency Division Multiplexing is one of the widely used modulation techniques in the present broadband wireless technology. The opportunities and challenges of this modulation technique are derived from its native advantages and disadvantages. One of the main problems is the high peak-to-average power ratio of transmission signal due to the superposition of many subcarriers. This paper presents a new hybrid peak-to-average power ratio reduction technique, which combines an active constellation extension method with a tone reservation method. The paper presents the performance and advantages of the mixed technique and compares it with other existing methods. The simulations shown that the proposed technique realizes an increased peak-to-average power ratio reduction compared to component methods with similar parameters.
Efficient Techniques for PAPR Reduction in Multicarrier Communication
Orthogonal frequency division multiplexing (OFDM) is an efficient multi-carrier modulation technique for wireless communication. However, one of the main drawbacks in OFDM is high PAPR when non-linear power amplifiers are used. The resultant high peak-to-average power ratio (PAPR) degrades the system performance. The effects include a decrease in the bit error rate (BER), an increase in complexity, or a reduction in the bit rate. The objective of this paper is to describe the PAPR problems in a bid to reduce the peaks in the OFDM signal. In this paper, hybrid techniques for PTS and DCT is used to reduce the PAPR of the OFDM system. Simulations are performed at 64,128,256 and 1024 carriers using MATLAB software.CCDF graphs demonstrate the efficiency of proposed techniques.
Peak to Average Power Ratio (PAPR) Reduction in OFDM System
2006 International RF and Microwave Conference, 2006
Orthogonal Frequency Division Multiplexing (OFDM) is a special form of multicarrier modulation which is robust against the multipath effect, Intersymbol Interference (ISI) and high spectral efficiency. However, Peak to Average Power Ratio (PAPR) is a major drawback in the system since this leads to the distortion problem in the linear devices such as the power amplifier (PA). Thus, the PAs require a backoff which is approximately equal to the PAPR for distortionless transmission. This decreases the efficiency for amplifiers. Hence, reducing the PAPR is the main focus of this paper. One of the available PAPR solutions is clipping. In the technique, the efficiency does not depend on the number of carriers. This paper investigates the effectiveness of the clipping technique by focusing on the performance of PAPR value with different values of clipping ratios (CRs) and the relationship between PAPR value and Bit Error Rate (BER).
OFDM PAPR Reduction by Shifting Two Null Subcarriers among Two Data Subcarriers
Orthogonal frequency division multiplexing (OFDM) is an attractive modulation technique for transmitting large amount of digital data over radio waves. High PAPR of the transmit signal is major drawback of OFDM. Proposed method promises PAPR reduction by shifting and switching null subcarrier with data subcarrier. When it is compared with existing reduction techniques (Such as Shifting Null Subcarrier among Data Subcarrier, Interleaving Technique, PTS, SLM, Tone rejection etc), the proposed method is compatible with current commercial system. The MATLAB simulations show a PAPR reduction of around 1.4dB using the proposed method than the existing methods also BER performance of proposed method is much better than that of existing methods.
Improving PAPR Reduction for OFDM using Hybrid Techniques
— The Peak-to-Average Power Ratio (PAPR) reduction in Orthogonal Frequency Division Multiplexing (OFDM) system has gained widespread attention during the last decade, leading to the development of several techniques for PAPR reduction. To benefit from these techniques while overcoming their inherent shortcomings, more recent work shows the use of hybrid variants of these techniques. In this paper, we present a brief overview of the hybrid techniques adapted for PAPR reduction. We also comment on the computational complexity and practicability of these approaches. Furthermore the paper covers a variety of hybrid techniques combining simple schemes e.g. clipping, companding and more complex schemes such as partial transmit sequence.
Reduction of peak to average power ratio ( PAPR ) in orthogonal frequency division multiplexing ( OFDM ) system 1
2014
In advance communication field there should be high data rate in addition to power efficiency and low bit error rate. This demand of high data rate can be fulfilled by single carrier modulation but compromising the trade-off between power efficiency and bit error rate. Again in the presence of selective fading environment it is difficult in case of single carrier modulation to achieve high data rate with low bit error rate performance. To overcome these problems advance step towards multicarrier modulation scheme is possible to get high data rate in this selective fading channel with low bit error rate performance. To achieve better performance using multi carrier modulation we make the subcarriers to be orthogonal to each other and the technique is called as the Orthogonal Frequency Division Multiplexing (OFDM). But the greatest disadvantage of the OFDM technique is its high Peak to Average Power Ratio (PAPR). Here in this paper we will describe how PAPR is increased and its reduct...
A new proposed peak-to-average power reduction parameter to evaluate SLM and PTS as OFDM PAPR reduction schemes
2013 IEEE Student Conference on Research and Developement, 2013
Two techniques of the most known ones for peak to average power ratio (PAPR) reduction of orthogonal frequency division multiplexing (OFDM) are selected mapping (SLM) and partial transmit sequence (PTS). Both schemes were proposed as distortion less PAPR reduction algorithms. However, it has been an argument to prove which scheme is the most efficient. In this paper, we propose a new PAPR reduction efficiency parameter which will be applied on the complementary cumulative distribution function (CCDF) of each technique to compare the results. We show as well how the performance of the system reacts when increasing the probability of getting high PAPR values. Using the proposed efficiency formula, we show that PTS system performance improves when increasing the probability, whereas the SLM system performance gets impaired when increasing the probability within the same range.
Related papers
Novel Technique For PAPR and Average Power Reduction In OFDM Scheme
IJATCSE, 2019
Orthogonal frequency division multiplexing (OFDM) is a multicarrier modulation technique that relies on orthogonality feature to increase transmission data rate while enhancing spectral efficiency at the same time. OFDM's major issue is the high peaks or peak-to-average power ration (PAPR) that introduced due to summation of subcarriers' signal. Many methods has been proposed to alleviate this issue however some may increase signal average power. In this paper, a new scrambling method using simple XOR operation is proposed for PAPR and average power reduction in OFDM system.
Adaptive Hybrid PAPR Reduction in OFDM System
International Journal of Future Computer and Communication, 2013
High Peak to Average Power Ratio (PAPR) is still one of the most important challenges in Orthogonal Frequency Division Multiplexing (OFDM) system. In this paper, we propose a novel scheme based on Selected Mapping (SLM) technique for PAPR reduction in OFDM system. The proposed scheme is an adaptive hybrid scheme, which is based on the SLM technique and multiple transformation techniques. In the proposed scheme, instead of using only Discrete Fourier Transform (DFT) in OFDM system, we suggest to use Discrete Sine Transform (DST) and Discrete Cosine Transform (DCT) as well to get the lowest PAPR. In addition, the multiplied phase in the SLM is adapted to reduce the PAPR to an acceptable low PAPR level. Simulation results show that the proposed scheme technique can reduce the PAPR to about 4 dB in case of 256 sub-carriers and in case of 512 sub-carriers at clipping probability of 10 -3 .
PAPR Reduction of OFDM Signals using Gradual Projection Active Constellation Extension and Sequential Block Grouping Tone Reservation Hybrid Scheme
2012
The Orthogonal Frequency Division Multiplexing is one of the widely used modulation techniques in the present broadband wireless technology. The opportunities and challenges of this modulation technique are derived from its native advantages and disadvantages. One of the main problems is the high peak-to-average power ratio of transmission signal due to the superposition of many subcarriers. In previous works, various hybrid peak-toaverage power ratio reduction techniques were presented. One of these techniques was the combination of the standard active constellation extension with the sequential tone reservation scheme. This paper presents a new hybrid peak-to-average power ratio reduction technique, which combines other active constellation extension and tone reservation schemes. This is the case of already known smart gradient projection and new proposed signal compression gradual projection active constellation extension and sequential block ordered tone reservation scheme respe...
A COMPARATIVE SURVEY ON PAPR REDUCTION TECHNIQUES FOR OFDM PERFORMANCE IMPROVEMENT
The Orthogonal Frequency Division Multiplexing is one of the modulation techniques widely used in the broadband wireless technology. One of the main problems of this technology is the high peak-to-average power ratio of transmission signal due to the superposition of many subcarriers. This paper presents a comparative studies of peak-to-average power ratio reduction technique, which compares among the selective mapping method, clipping method and Tone reservation techniques for PAPR reduction. The paper presents the performance of these different PAPR reduction techniques and compares it with unreduced PAPR.
PAPR Reduction using Combined Coding , Weighting , and Mapping in OFDM Systems 1
2002
In this paper we present methods for reduction of Peak-to-Average Power Ratio (PAPR) in multi-carrier Orthogonal Frequency Division Multiplexing (OFDM) through the joint use of coding, weighting, and signal mapping. Simple and easyto-implement coding schemes have been identified that when employed with suitable weighting functions can reduce PAPR considerably. Indeed it is shown that PAPR can be controlled by appropriate choice of coding scheme and weighting function for a given signal mapping. A thorough numerical investigation using computer simulations is presented and schemes that offer considerable reduction in PAPR are identified as a function of number of sub-carriers in OFDM systems.
Performance Improvement in OFDM System by PAPR Reduction
Signal & Image Processing : An International Journal, 2012
Power Ratio (PAPR) of the transmitted signals. OFDM consist of large number of independent subcarriers, as a result of which the amplitude of such a signal can have high peak values. Coding, phase rotation and clipping are among many PAPR reduction schemes that have been proposed to overcome this problem. Here two different PAPR reduction methods e.g. partial transmit sequence (PTS) and selective mapping (SLM) are used to reduce PAPR. Significant reduction in PAPR has been achieved using these techniques. The performances of the two methods are then compared.
PAPR Reduction for Improved Efficiency of OFDM Modulation for Next Generation Communication Systems
International Journal of Electrical and Computer Engineering (IJECE)
Highly linear power amplifiers are required for transferring large amount of data for future communication. Orthogonal frequency division multiplexing (OFDM) provides high data rate transmission capability with robustness to radio channel impairments. It has been widely accepted for future communication for different services. But, it suffers from high value of peakto-average power ratio (PAPR). High value of PAPR drives high power amplifiers in saturation and causes it to operate in the nonlinear region. In this paper, comparative study of four different PAPR reduction techniques: clipping and filtering (CF), selective mapping method (SLM), partial transmit sequence (PTS) and DFT-spread technique have been done. Mathematical modeling and Matlab simulations have been performed to arrive at the results with 4 QAM modulation format and 1024 number of sub carriers. At 0.01 % of complementary cumulative distribution function (CCDF) significant reduction of 11.3, 3.5, 3.4 and 1.0 dB have been obtained with DFT-spread, SLM, PTS and CF techniques respectively.
Comparative Study of Papr Reduction Techniques in Ofdm
International Journal of Advance Engineering and Research Development, 2017
Orthogonal Frequency Division Multiplexing (OFDM) is considered to be a promising technique against the multipath fading channel for wireless communications. However, OFDM faces the Peak-to-Average Power Ratio (PAPR) problem that is a major drawback of multicarrier transmission system which leads to power inefficiency in RF section of the transmitter. This paper present different PAPR reduction techniques and conclude an overall comparison of these techniques. We also simulate the selected mapping technique (SLM) for different route number which is most efficient technique for PAPR reduction when the number of subcarrier is large. Simulation shows that the PAPR problem reduced as the route number increases.
Improving Effectiveness of the Active Constellation Extension Method for PAPR Reduction in Generalized Multicarrier Signals
Wireless Personal Communications, 2010
In this paper, the Active Constellation Extension (ACE) method of Peak-to-Average Power Ratio (PAPR) reduction is studied for the application in Generalized Mulicarrier (GMC) transmission using nonorthogonal subcarriers. It is shown, that GMC signaling is advantageous for modern wireless communications due to its high spectral efficiency, however, it faces even higher PAPR than in the case of the conventional Orthogonal Frequency Division Multiplexing (OFDM) transmission. The modification of the ACE method for the GMC signals is presented, which takes into account overlapping of data symbol pulses and of their subband spectra. Further improvements of the proposed method are suggested that lead to the decrease of the computational complexity and to more efficacious PAPR reduction in comparison with the conventional ACE scheme. With these improvements, the PAPR reduction for the GMC signaling is the same as for OFDM.
PAPR REDUCTION USING EFFICIENT PEAK CLIPPING TECHNIQUE IN OFDM SYSTEMS
Orthogonal frequency division multiplexing (OFDM) is the most popular modulation technique which is used for high speed communication system. It provides high spectral efficiency and low implementation complexity. However the main issue of OFDM is its high Peak to Average Power Ratio (PAPR) which results from sum of several sinusoidal signals. So the Efficient Peak Clipping Technique has used to reduce the peak-to-average power ratio (PAPR) of OFDM systems. By introducing different number of Subcarriers N, Up sampling factor k, Number of all samples n, Mapping Order M, and Phase Offset P, a desired level of PAPR has been achieved. At the same time by introducing the proposed technique better tradeoff between BER and SNR has been maintained.
Loading Preview
Sorry, preview is currently unavailable. You can download the paper by clicking the button above.