IJERT-PAPR Reduction in OFDM using Reduced Complexity Selective Mapping Technique (original) (raw)
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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.
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.
PAPR Reduction in the OFDM Signal Using Selective Mapping
Nowadays Orthogonal Frequency Division Multiplexing is becoming more and more popular Because of it is attractive techniques for high data rate transmission. OFDM is widely used in 4G technologies in recent times. Main advantage of OFDM is that it uses orthogonal signals so removes inter-signal interference. PAPR ratio in OFDM is very high because it uses Multicarrier modulation, which is its main drawback. High PAPR means more power need at transmission side. PAPR can be decreased using various techniques such as clipping, selective mapping, etc. In this paper, criterion for new scheme selective mapping is introduced for PAPR reduction in OFDM.
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)
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.
A Novel SLM Scheme for PAPR Reduction in OFDM Systems
Journal of Computer Networks and Communications, 2011
Orthogonal frequency-division multiplexing (OFDM) is an attractive transmission technique for high-bit-rate communication systems. One major drawback of OFDM is the high peak-to-average power ratio (PAPR) of the transmitter's output signal. A novel selected mapping (SLM) scheme is proposed, which employs matrix transformation, cyclically shifting, and linear combining algorithm to generate new candidates. The novel scheme requires only one IFFT and gets more candidate transmission signals throughout the entire process. The complexity analysis and simulation results show that this algorithm can dramatically reduce computational complexity comparing with the conventional SLM scheme as in Hill et al., 2000; Yang et al., 2009; Wang and Ouyang, 2005; Li et al., 2010; and Heo et al., 2007 under the similar PAPR reduction performance.
BEHAVIOUR OF OFDM SYSTEM AND REDUCTION OF ITS PAPR BY USING SELECTIVE MAPPING IN MATLAB
The OFDM technique divides the total bandwidth into many narrow sub-channels and sends data in parallel. It has various advantages, such as high spectral efficiency, immunity to impulse interference and, frequency selective fading without having powerful channel equalizer. But one of the major drawbacks of the OFDM system is high PAPR. OFDM signal consists of lot of independent modulated subcarriers, which created the problem of PAPR. It is impossible to send this high peak amplitude signals to the transmitter without reducing peaks. So we have to reduce high peak amplitude of the signals before transmitting. Communication is one in all the numerous features of existence. A new DSI-SLM method for PAPR reduction in OFDM system state that the phase sequence and dummy sequences added to the signal improves the PAPR reduction in OFDM signals whereas less hardware resources and less time are required to achieve the desired result.
PAPR Reduction using CPM Mappers and SLM in OFDM Systems
2015
Orthogonal Frequency Division Multiplexing (OFDM) system with Continuous Phase Modulation (CPM) mappers is considered. Such a system is known to provide superior bit error rate performance by virtue of the memory introduced by the CPM mapper compared to OFDM systems with conventional memoryless mappers such as BPSK and QPSK. In this paper, the ability of CPM mappers in an OFDM system to reduce Peak-to-Average Power Ratio (PAPR) is examined as a function of modulation parameters of mappers and the number of subcarriers used in the system. Firstly, three subclasses of CPM mappers, namely, single-h CPFSK, multih CPFSK, and Asymmetric multi-h CPFSK are considered and their PAPR performance is assessed. Next, these mappers in conjunction with SLM technique are considered and their PAPR performance is examined. A comparison of the PAPR reduction capability of CPM mappers relative to memoryless BPSK mappers in an OFDM system is presented. It is noted that, in general, CPM mappers offer sup...
AIP Conference Proceedings, 2016
High Peak-to-Average Power Ratio (PAPR) is known to be an unavoidable problem in Orthogonal Frequency Division Multiplexing (OFDM). In this paper, a modified Selective Mapping (SLM) to minimize the high PAPR in OFDM system with low computational complexity is proposed. This technique utilizes the Circulant Shift Codeword technique to the conventional SLM. This technique is utilizing the circulant shift that needs two or more bits in a codeword for shifting. The simulation results show a 27.6% improvement in minimizing high PAPR with minimum Inverse Fast Fourier Transform (IFFT) blocks used. Modified SLM technique minimizes more than 70% of the IFFT blocks compare to conventional SLM. Thus, the computational complexity which is based on the number of IFFT block can be reduced.
REDUCTION OF THE PAPR EFFECT IN OFDM SYSTEMS USING SELECTIVE MAPPING TECHNIQUE
The high peak-to-average power ratio (PAPR) of the transmitted signal in Orthogonal Frequency Division Multiplexing (OFDM) system. It leads to problems as which distorts the signal if the transmitter contains nonlinear components such as power amplifiers and causes some deficiencies such as inter-modulation, spectral spreading and changing in signal constellation. The favorite properties of OFDM signal is it has high spectral efficiency, robustness to channel fading, immunity to impulse interference, uniform average spectral density, capability of handling very strong echoes and less nonlinear distortion. Even though here are many advantages of OFDM, it has two main drawbacks, they are high PAPR and frequency offset. The result of the PAPR effect in OFDM system is investigated and proposed a novel approach to reduce PAPR effect using selective mapping (SLM) technique.