Linear Companding Transform for the Reduction of Peak-to-Average Power Ratio of OFDM Signals

Abstract

Vibration-based condition monitoring (VBCM) is• Vibration sensors are non-intrusive and can be contactless, facilitating non-destructive condition monitoring.

Companding schemes based on transforming signal statistics into trigonal distributions for PAPR reduction in OFDM systems

“…In this section, performance results of the proposed companding transforms are compared with other three companding transforms, C 1 (·), C 2 (·) in [12] and linear companding transform in [11] We consider an OFDM system with 256 subcarriers and QPSK modulation.…”

“…The simulation results of PAPRs are close to the calculated PAPRs. The proposed companding transforms T 2 (·), T 3 (·), and T 4 (·) can provide better PAPR performance compared with the linear companding transform in [11] In the simulation for evaluating BER performance, solid-state power amplifier (SSPA) is employed and the radio channel is assumed to AWGN. The random positive-integer parameter of SSPA is set to be the typical value 2.…”

“…Figure 6 depicts the profiles of the proposed four companding transforms and other three companding transforms, C 1 (·), C 2 (·) in [12], and linear companding transform with two inflexion points in [11]. In order to keep original signals and companded signals at the same average power level, the proposed companding transforms compress signals with large amplitude and expand signals with small amplitude.…”

An Overview of Peak-to-Average Power Ratio Reduction Techniques for OFDM Signals

“…Although, this companding scheme can reduce PAPR effectively, the computational complexity is increased at the same time. Then, a low-complexity linear companding transform (LCT) was investigated in [46] to reduce peak power by linearly transforming the small and large signal amplitudes with different scales. But this method can not keep signal power at the same level for the input and output.…”

High Power Amplifier Pre-Distorter Based on Neural-Fuzzy Systems for OFDM Signals

“…On the other hand, if some distortion is allowed, the envelope fluctuation can be reduced significantly In this group of distortion-based techniques can be found techniques such as AC (Amplitude Clipping) [16], ACF (Amplitude Clipping and Filtering) [17], TI (Tone Injection) [10], ACE (Active Constellation Expansion) [18] or similar approaches to ACE [19]. Besides, there are also companding methods such as in [20] for peak power reduction.…”