Variable code length RLL coding and decoding method based on visible light communication

• Main Authors: LI SHIYIN, LI ZONGYAN, YU HONGLU, SUN SHAOXIANG
• Format: Patent
• Language: Chinese; English
• Published: 24.09.2019
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

The invention discloses a variable code length RLL coding and decoding method based on visible light communication, and the method comprises the steps of A, setting the maximum value of the minimum code distance of each group of codes for an RLL code with a 2/3 code rate; B, establishing an FSM graph, analyzing a possible state path graph corresponding to coding when the minimum code distance is different so as to obtain a grid graph; C, on the basis of the RLL code obtained in the step B, after the Gaussian white noise is added to the RLL code, decoding through a BCJR algorithm, and obtaining the expressions of a forward recurrence metric, a backward recurrence metric and a state transition metric in the BCJR algorithm; and D, based on the expression obtained in the step C, decoding the respective log-likelihood ratios of the output information sequences. According to the method, the transmission reliability of the visible light signals can be improved under the condition that the code rate is not changed, a