Method and apparatus for decreasing peak-to-average power ratio of three-dimensional coherent optical orthogonal frequency division multiplexing system

Abstract

The invention discloses a method and apparatus for decreasing a peak-to-average power ratio of a three-dimensional coherent optical orthogonal frequency division multiplexing system. The method comprises the following steps: (1) converting a binary sequence to obtain a subcarrier index signal; (2) mapping to obtain a frequency-domain orthogonal frequency division multiplexing signal of 3N real-form subcarrier components; (3) recombining to obtain a frequency-domain orthogonal frequency division multiplexing signal of 2N plural-form subcarrier components; (4) modulating the orthogonal frequency division multiplexing signal from the frequency domain to a time domain; (5) introducing a K sequence from the frequency domain, performing zero padding, and superimposing with the time-frequency orthogonal frequency division multiplexing signal after the modulation; (6) searching a K sequence combination with a minimum signal peak-to-average power ratio; (7) dividing the time-domain orthogonal frequency division multiplexing signal into a real-number portion and an imaginary-number portion corresponding to the real-number portion, and converting to an optical signal; and (8) transmitting the optical signal. By adopting the method and the apparatus, the peak-to-average power ratio is effectively decreased, the influence of a nonlinear action of an optical-fiber channel on the signal can be alleviated, and the overall performance can be improved.

Description

technical field [0001] The invention relates to the field of optical communication, in particular to a method and a device for reducing the peak-to-average power ratio (PAPR) of a three-dimensional coherent optical orthogonal frequency division multiplexing (OFDM) system. Background technique [0002] In the field of optical communication, coherent optical orthogonal frequency division multiplexing technology has been widely used in long-distance optical fiber transmission systems. It has the advantages of large capacity, high spectrum utilization, and effective anti-dispersion. However, there is a problem that the peak-to-average power ratio is too high when the OFDM technology is used, which makes the OFDM signal susceptible to interference from the nonlinear effect of optical fiber, resulting in a decrease in system performance. [0003] At present, OFDM technology based on constant envelope and OFDM technology based on coding are usually used to improve the peak-to-avera...

AI Technical Summary

Problems solved by technology

However, there is a problem of high peak-to-average power ratio when OFDM technology is used, which makes OFDM signals susceptible to interference from optical fiber nonlinear effects, resulting in system performance degradation

[0003] At present, OFDM technology based on constant envelope and OFDM technology based on coding are usually used to improve the peak-to-average power ratio of coherent optical OFDM systems, but the above The constellation diagrams used in the method for signal mapping are limited to two-dimensional signal space, which limits the improvement of system performance

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