SELECTED MAPPING, CLIPPING AND DIFFERENTIAL SCALING FOR REDUCTION OF PAPR IN OFDM SYSTEM (original) (raw)
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Systematic Comparison of Different PAPR Reduction Methods in OFDM Systems
2014
Selected mapping (SLM) is a well-known technique for peak to-averagepower ratio (PAPR) reduction of orthogonal frequency-division multiplexing (OFDM) systems. In this technique, different representations of OFDM symbols are generated by rotation of the original OFDM frame by different phase sequences, and the signal with minimum PAPR is selected and transmitted. To compensate for the effect of the phase rotation at the receiver, it is necessary to transmit the index of the selected phase sequence as side information (SI). In this paper, an SLM technique is introduced for the PAPR reduction of space-frequency-block-coded OFDM systems with Alamouti coding scheme. In this paper, we also propose a simple technique for the reduction of high Peak to Average Power Ratio (PAPR), based on Clipping and Differential Scaling, in Orthogonal Frequency Division Multiplexing (OFDM) systems. In this technique, the amplitude of complex OFDM signal is clipped and then scaled in such a way so that the ...
Improved Selected Mapping Technique for Reduction of PAPR in OFDM Systems
International Journal of Advanced Computer Science and Applications, 2020
High peak to average power ratio (PAPR) is a limiting factor towards the performance of an OFDM system. Selected Mapping (SLM) is a popular peak to average power ratio (PAPR) reduction scheme used with the OFDM systems. In this technique, U set of candidate sequences are generated that leads to improvement in the PAPR reduction ability of the OFDM systems. The major concern of the conventional SLM is that as the number of candidates is increased, there is a proportional rise in the inverse fast Fourier transforms (IFFT) computations of the systems. In our article we have proposed a scheme in which we increase the number of candidate sequence as (U+U 2 /4) that leads to improved PAPR performance of the OFDM systems without any equivalent rise in the IFFT computations. It has been demonstrated that both the simulation and analytical results are well-approximated in our proposed schemes. We also estimate the threshold value of PAPR at a fixed value of complementary cumulative distribution function (CCDF) for different number of subcarriers and candidate sequences. Results demonstrate that our proposed scheme outperforms in terms of PAPR reduction ability of the OFDM signal and obtains effective PAPR threshold values with negligible loss in BER performance of the system.
Analysis of Peak to Average Power Ratio Reduction Techniques in Sfbc Ofdm System
IOSR Journal of Electronics and Communication Engineering, 2013
Orthogonal Frequency Division Multiplexing (OFDM) has become the most popular modulation echnique for high speed data transmission. But the great disadvantage of the OFDM technique is its high Peak to Average Power Ratio (PAPR). In this paper, the Selected Mapping (SLM) technique and Clipping and Differential Scaling is applied to Space Frequency Block Coded (SFBC) OFDM systems to reduce the PAPR with Alamouti coding scheme. In SLM technique, different representations of OFDM symbols are generated by rotation of the original OFDM frame by different phase sequences, and the signal with minimum PAPR is selected and transmitted. To compensate for the effect of the phase rotation at the receiver, it is necessary to transmit the index of the selected phase sequence as side information (SI). Additionally, a suboptimum detection method that does not need SI is introduced at the receiver side. In Clipping and Differential Scaling technique, the amplitude of complex OFDM signal is clipped and then scaled in such a way so that the PAPR is reduced without causing much degradation in bit error rate (BER). The threshold values for clipping and scaling is determined using Monte Carlo Simulations. Simulation results show that the SLM method and Clipping and Scaling method effectively reduce the PAPR.
A novel selected mapping technique for PAPR reduction in OFDM systems
IEEE Transactions on Communications, 2008
Selected mapping (SLM) is a well-known method for reducing the peak-to-average power ratio (PAPR) in orthogonal frequency-division multiplexing (OFDM) systems. The main drawback of this technique is that, for each data block, it requires the transmission of several side information bits, which results in some data rate loss. These redundant bits are so critical to the error performance of the system that they need in practice to be protected by a powerful channel code. This increases the system complexity and transmission delay, and decreases the data rate even further. In this paper, we propose a novel SLM method for which no side information needs to be sent. By considering the example of an OFDM system using 16-QAM modulation, it is shown that the proposed method performs very well both in terms of PAPR reduction and bit error rate at the receiver output.
PAPR reduction of Coded OFDM signal using Selective Mapping Technique
Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier modulation (MCM) technique which seems to be an attractive candidate for fourth generation (4G) wireless communication systems. Peak-to-average Power ratio(PAPR) problem is the major drawback of multicarrier transmission system which leads to power inefficiency.There are various techniques which can be used to reduce PAPR.In this paper Selective mapping technique(SLM) is used to reduce PAPR of coded OFDM signal. Peak-to-Average Power Ratio(PAPR), Complementary Cumulative Distribution Function (CCDF), Selective Mapping(SLM),Partial Transmit Sequence (PTS).Reed Solomon(RS)
Coding Schemes Applied to Peak-to-Average Power Ratio (PAPR) Reduction in OFDM Systems
International Conference on Wireless Communications and Mobile Computing, 2008
High PAPR of the transmitted signal is a major drawback in the OFDM systems. In this paper, coding schemes are proposed to reduce high PAPR One is using parity check coding scheme, and the other is using selected mapping (SLM) applied scheme. With parity check coding scheme, the parity information is used to expand the signal space. Mapping from original
PAPR REDUCTION OF OFDM SIGNALS USING SELECTIVE MAPPING AND CLIPPING HYBRID SCHEME
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 new hybrid peak-toaverage power ratio reduction technique, which combines a selective mapping method with the clipping method. The paper presents the performance and advantages of the new technique and compares it with other existing methods.
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.
International Journal of Engineering Research and Technology (IJERT), 2013
https://www.ijert.org/modified-peak-to-average-power-ratio-papr-reduction-scheme-for-orthogonal-frequency-division-multiplexing-ofdm-signals https://www.ijert.org/research/modified-peak-to-average-power-ratio-papr-reduction-scheme-for-orthogonal-frequency-division-multiplexing-ofdm-signals-IJERTV2IS120549.pdf Orthogonal frequency division multiplexing (OFDM) is an efficient parallel data transmission scheme, in which high data rates can be achieved by transmitting a number of orthogonal subcarriers. The main reason for increasing interest in the OFDM system is the way it handles multipath fading phenomenon that is inherent with the wireless channels. OFDM has been considered for fourth generation (4G) transmission technique. One major disadvantage of OFDM is that the time domain OFDM signal which is a sum of several sinusoids leads to high peak to average power ratio (PAPR). High PAPR involves the development of non-linear distortions .The work done is a joint companding transform and hadamard transform method is proposed to reduce peak-to-average of OFDM signal. Simulation results show that the proposed scheme obtain significant PAPR reduction while maintaining good performance in the BER compared to ordinary companding method.
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.