Encoding and decoding method for optical code division multiplexing system

Abstract

The embodiment of the invention discloses an encoding and decoding method for an optical code division multiplexing system. The method comprises the following steps that the codeword number M of encoding codewords is selected according to the coherence length of light carriers and the pulse width of the light carriers; the M codewords are selected as encoding codewords of a receiving end; a sending end carries out encoding on modulating signals sent to the receiving end by the encoding codewords according to preset code hopping rules, and an encoding signal is generated; the receiving end receives the encoding signal sent by the sending end; the receiving end carries out decoding on the encoding signal by the encoding codewords of the receiving end according to the preset code hopping rules. The technical scheme has the advantages that on the basis of guaranteeing the transmission security of the system, the complexity of the system is effectively reduced, and the transmission efficiency is improved.

Description

technical field [0001] The invention relates to an optical code division multiplexing technology, in particular to an encoding and decoding technology of an optical code division multiplexing system. Background technique [0002] Optical Code Division Multiplexing (OCDM for short) is a technology widely used in optical communication to solve channel multiplexing of multiple users. The main process of optical communication based on OCDM system includes: [0003] 1. Allocate codewords for the receiving end; [0004] 2. The sending end modulates the original signal sent to the receiving end to generate the modulated signal of the receiving end; [0005] 3. Encoding the modulated signal at the receiving end with the encoded codeword; generating the encoded signal at the receiving end; [0006] The encoding is to perform convolution with the encoded codeword and the modulated signal; [0007] 4. Sending the encoded signal to the receiving end; [0008] 5. The receiving end u...

AI Technical Summary

Problems solved by technology

After encoding with multiple encoding codewords, the encoding codewords of two adjacent bits that are both '1' (or both '0') may be different, and their phases may also be different. In this way, through a simple phase detection makes it difficult to judge the original signal corresponding to these two bits

[0017] Although the above-mentioned encoding method in the prior art can resist phase detection eavesdropping to a certain extent, and improves the security of the OCDM system based on DPSK or PSK modulation; but it also has certain problems: this method cannot ensure the signal transmission at the receiving end The number of codewords required for security codewords; in order to prevent eavesdropping, the prior art usually uses a larger number of codewords for a single receiving end, but too large a number of codewords will cause high complexity of the system, and the transmission Efficiency is reduced; and if the number of codewords is too small, signal eavesdropping can still be achieved by using phase detection technology, which cannot guarantee the transmission security of the system, and the existing technology scheme cannot determine how many codewords to effectively resist the eavesdropping of phase detection technology

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