Visible light communication (VLC) can provide short-range optical wireless communication, together with illumination using light-emitting diode (LED) lightings. Since conventional forward error correction (FEC) codes cannot provide two lighting related features, dimming support, and flicker mitigation, the existing coding schemes for reliable VLC usually rely on auxiliary coding techniques, which cause a complicated structure and a low transmission efficiency. In this paper, based on polar codes, an efficient and flicker-free FEC coding scheme for dimmable VLC is proposed to increase the transmission efficiency and simplify the coding structure. Taking advantage of polar codes’ recursive encoding structure, the proposed scheme can guarantee the equal probability and the short runs of 1 s and 0 s for arbitrary code rate without extra coding components. Numerical results show that the proposed scheme can have twice higher transmission efficiency than the existing schemes. Furthermore, at a dimming ratio of @math or @math , the coding gain of the proposed scheme is about 4.6 dB and 1.4 dB higher than that of the Reed–Solomon (RS) codes based scheme and the low-density parity check code based scheme, respectively.
Two coding schemes based on modified Reed-Muller (RM) codes and minimal use of CSs have been proposed by Kim and Jung for dimming support in VLC systems @cite_5 @cite_21 . Although the RM codes-based schemes can guarantee the DC balance at exact 50 To overcome the limitation of RM codes-based scheme, two kinds of coding schemes using advanced error correction codes were proposed. The first one is a turbo codes-based coding scheme proposed by Lee and Kwon @cite_15 . However, it requires code puncturing, pseudo-noise sequence scrambling and CSs inserting to avoid long runs of 1s or 0s and to match the codewords' weight with the desired dimming ratio, introducing high coding overhead. Besides, for the dimming ratios greater than @math , all the binary symbols of the codewords need to be flipped to obtain those dimming ratios. Otherwise, the puncturing rate will be too high and make the information in a message indistinguishable.
@cite_5 @cite_15 @cite_21
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In this letter, we propose a novel forward error correction (FEC) coding method using a modified Reed-Muller (RM) code for providing accurate dimming control in on-off keying (OOK) based visible light communication (VLC) systems. The proposed FEC scheme has a property that produces exactly same occurrence probability of 1's and 0's. Therefore, it can contain minimal compensation symbols in supporting multiple dimming target values. Moreover, VLC with our proposed scheme provides more coding gain than VLC scheme with the conventional FEC codes [the first-order RM and Reed-Solomon (RS) codes]. Simulation results for various dimming target values show that the proposed scheme leads to at least 2 dB or more signal-to-noise ratio (SNR) gain in 1 bit error rate (BER) than two FEC codes. In this letter, we propose a new forward error correction (FEC) coding method using a coset constructed from a bent function and a Reed-Muller (RM) code for providing accurate dimming control in on-off keying-based visible light communication (VLC) systems. By partitioning the coset made from bent function and the first-order RM codes, the new FEC scheme can be made to be suitable for dimming close to 0 or 100 . Therefore, it can contain minimal compensation symbols in supporting multiple dimming target values, which causes improved coding gain when the total amount of frame data is fixed. Simulation results for various dimming target values show that the proposed scheme leads to about 1-dB signal-to-noise ratio gain in 10-2 bit error rate compared with other three FEC codes. This letter presents an error correction scheme for dimmable visible light communication systems. To provide dimming control of on-off keying, the proposed coding scheme yields a codeword with the codeword weight adapted to the dimming requirement. It also allows an arbitrary value of the dimming requirement unlike existing coding schemes which have a limited support of this feature. To this end, turbo codes are employed together with puncturing and scrambling techniques to match the Hamming weight of codewords with the desired dimming rate. We demonstrate the decoding performance of the proposed coding scheme under iterative decoding and compare it with other existing error correction schemes. The simulation results prove that the proposed scheme has superior decoding performance, arbitrary dimming rate support, and diverse code rate options. In this letter, we propose an adaptive forward error correction scheme based on low-density parity-check (LDPC) codes to efficiently adjust dimming values in visible light communication (VLC) systems. The proposed code is a quasi-cyclic LDPC code, in which extension and puncturing methods are used to maintain dimming control. The significant advantages of the proposed method are due to the lower number of codes required to support codes with different coding rate and the relatively small performance degradation for dimming control. Simulation results show that our proposed method efficiently maintains the dimming control in VLC systems with LDPC codes.