A Low-Complexity SLM PAPR Reduction Scheme for OFDMA

In orthogonal frequency division multiplexing (OFDM) systems, selected mapping (SLM) techniques are widely used to minimize the peak to average power ratio (PAPR). The candidate signals are generated in the time domain by linearly mixing the original time-domain transmitted signal with numerous cyclic shift equivalents to reduce the amount of Inverse Fast Fourier Transform (IFFT) operations in typical SLM systems. The weighting factors and number of cyclic shifts, on the other hand, should be carefully chosen to guarantee that the elements of the appropriate frequency domain phase rotation vectors are of equal magnitude. A low-complexity expression is chosen from among these options to create the proposed low-complexity scheme, which only requires one IFFT. In comparison to the existing SLM technique, the new SLM scheme achieves equivalent PAPR reduction performance with significantly less computing complexity. MATLAB tool is used for simulating the proposed work

A Low-Complexity SLM PAPR Reduction Scheme for OFDMA

In orthogonal frequency division multiplexing (OFDM) systems, selected mapping (SLM) techniques are widely used to minimize the peak to average power ratio (PAPR). The candidate signals are generated in the time domain by linearly mixing the original time-domain transmitted signal with numerous cyclic shift equivalents to reduce the amount of Inverse Fast Fourier Transform (IFFT) operations in typical SLM systems. The weighting factors and number of cyclic shifts, on the other hand, should be carefully chosen to guarantee that the elements of the appropriate frequency domain phase rotation vectors are of equal magnitude. A low-complexity expression is chosen from among these options to create the proposed low-complexity scheme, which only requires one IFFT. In comparison to the existing SLM technique, the new SLM scheme achieves equivalent PAPR reduction performance with significantly less computing complexity. MATLAB tool is used for simulating the proposed work

Adjacent Partitioning Based MIMO-OFDM System with Partial Transmit Sequence for PAPR Reduction

The multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) transmission approach has been chosen to be a standard of fourth-generation (4G) wireless communication systems, but it has to cope with the main disadvantages and challenges of OFDM-based techniques, including the high peak-to-average power ratio (PAPR). Peak to average power ratio (PAPR) being a predictable random variable in multicarrier system and it can be minimized by different techniques. Complementary cumulative distribution function (CCDF) is used to describe the PAPR appropriately. Partial transmit sequence (PTS) is an attractive distortion less peak-to-average power ratio (PAPR) reduction technique for orthogonal frequency division multiplexing (OFDM) system. In this paper the performance of one of scrambling technique called partial transmit sequence (PTS) in MIMO-OFDM system and adjacent partitioning(one of the partitioning technique) in MIMO-OFDM system with PTS are analyzed based on the characteristics of CCDF DOI: 10.17762/ijritcc2321-8169.150514

On PAPR Reduction of OFDM using Partial Transmit Sequence with Intelligent Optimization Algorithms

In recent time, the demand for multimedia data services over wireless links has grown up rapidly. Orthogonal Frequency Division Multiplexing (OFDM) forms the basis for all 3G and beyond wireless communication standards due to its efficient frequency utilization permitting near ideal data rate and ubiquitous coverage with high mobility. OFDM signals are prone to high peak-to-average-power ratio (PAPR). Unfortunately, the high PAPR inherent to OFDM signal envelopes occasionally drives high power amplifiers (HPAs) to operate in the nonlinear region of their characteristic leading out-of-band radiation, reduction in efficiency of communication system etc. A plethora of research has been devoted to reducing the performance degradation due to the PAPR problem inherent to OFDM systems. Advanced techniques such as partial transmit sequences (PTS) and selected mapping (SLM) have been considered most promising for PAPR reduction. Such techniques are seen to be efficient for distortion-less signal processing but suffer from computational complexity and often requires transmission of extra information in terms of several side information (SI) bits leading to loss in effective data rate. This thesis investigates the PAPR problem using Partial Transmit Sequence (PTS) scheme, where optimization is achieved with evolutionary bio-inspired metaheuristic stochastic algorithms. The phase factor optimization in PTS is used for PAPR reduction. At first, swarm intelligence based Firefly PTS (FF-PTS) algorithm is proposed which delivers improved PAPR performance with reduced searching complexity. Following this, Cuckoo Search based PTS (CS-PTS) technique is presented, which offers good PAPR performance in terms of solution quality and convergence speed. Lastly, Improved Harmony search based PTS (IHS-PTS) is introduced, which provides improved PAPR. The algorithm has simple structure with a very few parameters for larger PTS sub-blocks. The PAPR performance of the proposed technique with different parameters is also verified through extensive computer simulations. Furthermore, complexity analysis of algorithms demonstrates that the proposed schemes offer significant complexity reduction when compared to standard PAPR reduction techniques. Findings have been validated through extensive simulation tests

A Novel PTS Scheme for PAPR Reduction of Filtered-OFDM Signals without Side Information

In this paper, a novel partial transmit sequence (PTS) scheme is proposed for reducing the peak-to-average power ratio (PAPR) of filtered orthogonal frequency division multiplexing (f-OFDM) systems. The PTS method is modified such that no side information (SI) transmission is needed. The data and pilot recovery are accomplished by a simple detector, making use of the correlation property of the Hadamard sequence and the transparency property of the pilot signal and an iterative phase detection is further added in a fading channel. Simulation results show that the modified solution provides a higher correct detection probability without increasing the system complexity nor affecting the PAPR suppression performance

Reduksi Peak-To-Average Power Ratio Pada Sistem STBC MIMO-OFDM Dengan Metode Selected Mapping Dan Partial Transmit Sequence

Teknik OFDM merupakan teknik multicarrier yang mengefisienkan bandwidth. Penggunaan teknik OFDM dapat mengatasi multipath fading dan intersymbol interference (ISI). Namun demikian, OFDM mempunyai dua kelemahan, salah satunya adalah peak-to-average power ratio (PAPR) yang tinggi. PAPR yang tinggi akan menyebabkan distorsi nonlinear pada high power amplifier (HPA) karena HPA membatasi keluaran dengan nilai tertentu dan mengurangi efisiensi daya amplifier. Oleh karena itu, PAPR yang tinggi harus direduksi. Metode reduksi PAPR yang diajukan adalah dengan menggunakan metode Selected Mapping (SLM) dan Partial Transmit Sequence (PTS). Kedua metode ini memiliki kekurangan dalam hal kompleksitas multiplikasi dan penjumlahan dan adanya bit side information yang harus dikirimkan ke receiver. Oleh karena itu, penulis mengajukan pengembangan dari metode tersebut dengan memodifikasi faktor rotasi fasa menjadi pattern konversi terdefinisi yang lebih adaptif pada SLM, dan mengurangi iterasi pembangkitan faktor rotasi fasa pada metode PTS dengan pendefinisian faktor rotasi fasa yang terbatas. Hasil simulasi dengan 1000 simbol OFDM menunjukkan bahwa kemampuan reduksi PAPR pada metode m-SLM dan m-PTS mendekati kemampuan reduksi metode konvensional. Bit error rate (BER) yang dihasilkan juga mengalami perbaikan dibandingkan BER tanpa reduksi. m-SLM secara keseluruhan mengungguli kinerja dari m-PTS, baik pada nilai reduksi PAPR maupun pada perbaikan BER