Peak-to-Average Power Ratio reduction in Wavelet based OFDM using Modified Selective Mapping for Cognitive Radio Applications

Abstract

The prospect of guaranteed quality of service for primary and secondary users in the expression of regulated Peak-to-Average Power Ratio (PAPR) and Bit Error Rate (BER) can be increased in Cognitive Radios using Wavelet based OFDM systems which localize spectrum in realms of time and frequency. However, cutting the Gordian knot of high PAPR associated with the Multi-Carrier Modulation schemes to operate in the linear part of the power amplifier nourishing the balance between PAPR and BER is difficult. In this paper, the phase of the subcarriers is altered by a value of finite, equally spaced phase shifts. The frame of Wavelet-based OFDM (WOFDM) with minimum PAPR guarantees the minimum quality of service (QoS) in terms of Throughput. BER is then identified and transmitted. This modification is applied to various Wavelets and compared amongst WOFDM and FFT-based OFDM schemes. The novelty of this paper lies in using Hadamard and/or Toeplitz matrix to generate phase sequences in a modified SLM technique of Wavelet-based OFDM systems while maintaining the minimum required QoS in Cognitive Radios. The result shows that the proposed technique reduces the PAPR compared to unmodified SLM techniques. HIGHLIGHTS Wavelet based OFDM systems localize spectrum in realms of time and frequency The sinusoid bases function in OFDM has been replaced by Wavelet bases Selective Mapping (SLM) is a popular technique towards PAPR reduction The primary function of the Cognitive Radio system is to identify the spectrum holes GRAPHICAL ABSTRACT

Modified Method of PAPR Reduction Using Clipping and Filtering for Image Transmission with OFDM

“…In Sharma et al [18], They found that OFDM has many advantages compared to single carrier modulation, such as Immunity to impulse interference, high spectral density, resilience to radio frequency (RF) interference, resilience to channel fading, multipath resilience, and much lower complexity of the computational process. Arjun and Surekhe [19] studies the performance of PAPR related to OFDM and wavelet OFDM (WOFDM) using modified selective mapping (SLM). The authors address two problems.…”

“…Different proposed techniques used for PAPR reduction are illustrated in [19][20][21][22][23], which are divided into three sets as shown in Figure 1. One of the simplest and most pragmatic approaches is clipping and filtering, which can limit the signal to the transmitter to eliminate the occurrence of high peaks above a certain level.…”

Performance Analysis of Combining Beamforming and ZF/MMSE-SIC Equalization Techniques for MIMO DWPT-COFDM Systems

“…An alternative approach utilizes the Inverse Discrete Wavelet Packet Transform (IDWPT) and DWPT algorithms, employing Wavelet Packets (WPs) as subcarriers instead of IFFT/FFT, overcoming issues like high Peak-to-Average Power Ratio (PAPR) and bandwidth wastage [18][19][20], with added improvements possible through antenna diversity techniques [21][22][23].…”

Low PAPR Filtered OFDM using Modified Selective Mapping

“…Apparently, Selective mapping is a well-accepted method to reduce the PAPR in OFDM systems particularly in 5G systems. With nearly two decades, SLM has been studied and noticed and applied for various OFDM systems to combat the PAPR problems and developed a special SLM methods for the variants of them; Alamouti coded MIMO-OFDM system, downlink power domain OFDM-NOMA systems [7], UW-OFDM systems [8], waveletbased cognitive radio for OFDM system [9], and non-coherent OFDM-IM system [10].…”