Performance Improvement for the Single Carrier in FBMC Systems by PAPR Reduction

Abstract

The benefits of Filter Bank Multicarrier (FBMC) make it an attractive waveform instead of orthogonal frequency division multiplexing (OFDM). However, a high peak-to-average power ratio (PAPR) is a significant drawback in FBMC. Exploiting a single carrier effect is considered an effective technique to reduce PAPR in FBMC systems with a small amount of additional complexity. Nevertheless, the PAPR reduction amount is different from the single carrier effect in the single carrier frequency division multiple access (SC-FDMA). This is because of the overlapping structure of the in-phase and quadrature (IQ) between offset quadrature amplitude modulation (OQAM) FBMC symbols. So, we introduce an algorithm, based on signal distortion techniques, to improve the performance of the single carrier effect techniques in the PAPR reduction for the FBMC systems. Simulation results depict that the single carrier effect techniques with the proposed algorithm achieve an extra amount of PAPR reduction compared to the same techniques without using the proposed algorithm. In addition, the simulation results show that the proposed algorithm maximizes the PAPR reduction amount without affecting the complexity.

A complexity efficient PAPR reduction scheme for FBMC-based VLC systems

“…The PAPR performance is calculated by the CCDF as it is more widely used in PAPR reduction performance evaluation. CCDF is defined as the probability that PAPR goes beyond a given threshold value that is given by (PAPR0), where its smaller values represent better performance [20]. This algorithm provides a further reduction in PAPR over the conventional DCO-FBMC.…”

“…The complex input data symbol is first multiplied to the phase shift pattern 𝑒 𝑗𝜑 𝑛,𝑚 where 𝜑 𝑚,𝑛 = 𝜑 𝑜 + 𝜋 2 (𝑚 + 𝑛) mod 𝜋. The purpose of using a phase shift is to make a 𝜋/2 phase shift between the neighbouring symbols transmitted along time and frequency [20].…”

“…Even though VLC-FBMC systems and RF-FBMC both have significant peak-to-average power ratio (PAPR), VLC-FBMC systems cannot be directly reduced using conven-tional PAPR reduction techniques [19], due to some differences between both systems. First, the transmitted RF-FBMC waveform is complex-valued [20], whereas the VLC-FBMC waveform is real-valued [21]. As a result, the lower and upper PAPRs of a real-valued FBMC waveform must be decreased.…”

“…As a result, the lower and upper PAPRs of a real-valued FBMC waveform must be decreased. Second, in RF transmission, both in-band distortions and out-of-band power loss are compensable using PAPR enhancement techniques [20]. Nevertheless, as LED can be considered a low-pass filter in visible FBM systems, out-of-band subcarriers cannot be used to send symbols [21].…”