On the Reduced Complexity Interleaving Method for OFDM PAPR Reduction

Many methods for OFDM Peak to Average Power Ratio reduction have been proposed during approximately last ten years. There are nowadays many research efforts on PAPR reduction methods with reduced computational complexity. The method presented in this paper is based on adaptive symbol selection principle, with several replicas of signal created using set of interleavers incorporated inside an IFFT block at OFDM transmitter. This paper also discusses some practical aspects of this method - influence of zero padding and pilot positions

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

FPGA Implementation of Circularly Shifted PTS Technique for PAPR Reduction in OFDM

In today’s world, the ongoing trend in 4G has adopted multi-carrier transmission schemes like OFDM, OFDMA and MIMO-OFDM. OFDM has proven to be one of the most promising schemes used for transmission of signals. It still exists with some of the drawbacks, out of which, the high peak to average power ratio gives rise to non-linear distortion, inter-symbol interference and out-of-band radiation. There has been various ways developed and implemented to reduce peak to average power ratio. Comparing between all the techniques to reduce peak to average power ratio, it has been found that the best method is partial transmit sequence technique. This technique was first proposed by Muller and Huber in the year 1997. Within the years there have been various modifications with this technique which has been proposed and implemented. Today’s world is a digital world where an analog form of communication can be transformed to digital form of communication. Weste and Skellern were the first to propose the OFDM method in VLSI. The partial transmit sequence technique in FPGA has been proposed by Junjun et.al. and Varahram et.al. In this thesis work an efficient FPGA implementation of circularly shifted partial transmit sequence (CS-PTS) scheme for peak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) signals has been carried out. It eliminates the search for optimum phase factors from a given set, which manifests improved PAPR at reduced computational complexity as compared to conventional PTS (C-PTS). The amplitude of the signal is reduced by rotating each of the partially transmitted sequence anti-clockwise by a pre-determined degree and the peak power is reduced by circularly shifting the quadrature component of the partially transmitted sequence after phase rotation

Multicarrier modulation with variable peak‐to‐average power ratio using partial fast Fourier transform

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/166180/1/cmu2bf01398.pd

FPGA-Based Realisation of SDR with OFDM Tranceiver

Software-defined radio architecture is the key point of next generation communication systems in which some of the functional units are designed as software on a reconfigurable processor. This paper proposes the physical layer architecture of SDR with modified orthogonal frequency division multiplexing (OFDM). One of the main drawbacks of OFDM is that its high peak-to-average reduction (PAPR) ratio. The PAPR can be reduced using filtering and adaptive peak windowing method with Kaiser window. The adaptive window method finds the positions of maximum peak values using a peak detector in the signal and applies the window function with variable parameter. The radix 2 scalable N point FFT algorithm is used in the system. The mapping of the information signal is done with BPSK, PSK, and 16 QAM modulation. According to the signal-to- noise ratio (SNR) value, the type of modulation can be selected. Decoding of the OFDM signal in the receiver is done with Viterbi decoding algorithm. The communication system simulation is done in MATLAB and the baseband operations are implemented on Xilinx FPGA.Defence Science Journal, Vol. 65, No. 3, May 2015, pp.233-239, DOI: http://dx.doi.org/10.14429/dsj.65.601

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