ASCO-OFDM based VLC system throughput improvement using PAPR precoding reduction techniques

Abstract

The huge bandwidth and immunity to electromagnetic interference make visible light communication (VLC) systems the preferred technique for many applications. Unfortunately, the superposition of multiple subcarriers in VLC orthogonal frequency division multiplexing systems leads to a high peak-to-average power ratio (PAPR). So, in this study, we aim to reduce PAPR in VLC systems and improve the system performance by proposing non-distorting PAPR reduction techniques like precoding techniques as it doesn’t affect the system data rate because they do not require any obligatory transmission of side information. Moreover, it has a very good ability to reduce the PAPR without affecting the system BER performance. So, different precoding reduction techniques are proposed like discrete cosine transform (DCT), discrete sine transform (DST), discrete Hatley transform (DHT), and Vandermonde like matrix (VLM), to address the high PAPR and light-emitting diode-restricted linear range problems in VLC systems. The proposed technique using DHT, DCT, DST, and VLM provided a significant advantage in reducing the PAPR by 1.35 dB, 1.46 dB, 2.12 dB, and 2.17 dB, respectively. So the proposed technique is based on using the VLM precoding technique to achieve maximum reachable PAPR reduction value. Also, a comparison of the presented work and related literature reviews for PAPR reduction techniques are held to ensure the validity and effectiveness of the proposed scheme.

Optical-OFDM VLC System: Peak-to-Average Power Ratio Enhancement and Performance Evaluation

“…To fulfill the non-negative signal requirement, any negative values within 𝑥 , (𝑛) and 𝑥 , (𝑛) are clipped to zero, yielding 𝑥 , , (𝑛), and 𝑥 , , (𝑛) as described below [21]: Both X ACO (K) and X EVEN (K) components are applied to IFFT operation as follows:…”

“…The overall composite signal was created by merging frames, each consisting of a defined number of symbols, each with a size of N. The signalling strategy in the first layer (𝐿 = 1) closely emulated that of ACO-OFDM, as elucidated in references [19,34,35]. This layer included N/4 CS, with their CC allocated in To fulfill the non-negative signal requirement, any negative values within x ACO,I (n) and x ACO,j (n) are clipped to zero, yielding x ACO,I,C (n), and x ACO,J,C (n) as described below [21]:…”

“…The intense peaks in the OFDM signal can cause LED chips to overheat. Consequently, prior to sending the O-OFDM signal via the LEDs, it is crucial to mitigate its high PAPR [21]. In this study, a PAPR reduction approach is used to solve the limited dynamic range of LEDs.…”

“…This paper introduces the utilization of the Vandermonde-Like matrix (VLM) pre-coding technique for various MCM methods previously mentioned. This precoding method minimizes PAPR effectively without sacrificing BER performance and operates without the need for supplementary side details or additional processing [21].…”

Partial Transmit Sequence Chaotic Sand Cat Swarm Optimization Based Phase Optimizer for Peak-to-Average Power Ratio Reduction

“…High PAPR reduced the process of HPA to amplify [12]. Generally, metaheuristic techniques are utilized to reduce implementation time and costs, because of their accurate engineering [13]. Hence, it faces issues like initial convergence, less search constancy, the trap of local optimal, inefficient search, and less population diversity and diverging from a solution of optimum [14].…”