Channel estimation method for improving receiving sensitivity of OQAM (Offset Quadrate Amplitude Modulation)-OFDM (Orthogonal Frequency Division Multiplexing) light transmission system

Abstract

The invention provides a channel estimation method for improving receiving sensitivity of an OQAM (Offset Quadrate Amplitude Modulation)-OFDM (Orthogonal Frequency Division Multiplexing) light transmission system, and aims at solving the problems that the traditional channel estimation algorithm for the light OQAM-OFDM cannot treat intersymbol interference and inter-subcarrier interference caused by the orthogonal damage of a subcarriers, and the decrease of the receiving sensitivity of the system caused by the accompanying gaussian noise and the like produced by devices in the system is ignored. The channel estimation method has the advantages that the interference approximating utilization based time-domain averaging channel estimation method (IATA-CE) comprising the steps of first-order LS channel estimation, second-order LS channel estimation and ZF balancing is performed during receiving to accurately estimate complex gain and phase response of a fiber channel; in addition, the interference from gaussian noise produced by the devices in the system can be resisted well; therefore, accurate channel estimation coefficients can be obtained, and as a result, the BER performance and receiving sensitivity of the system can be improved.

Description

technical field [0001] The invention relates to optical OFDM communication technology, in particular to a channel estimation method for improving the receiving sensitivity of an OQAM-OFDM optical transmission system. Background technique [0002] With the continuous emergence of various network emerging services, the number of users continues to increase, and the bandwidth requirements of users are also constantly increasing. In order to meet the needs of users and markets, the optical network transmission system that provides ultra-bandwidth services will be required to provide a data transmission rate of 1Tb / s or even higher on each sub-channel. As an emerging multi-carrier transmission scheme applied in high-speed optical transmission systems, interleaved quadrature amplitude modulation orthogonal frequency division multiplexing (Offset QAM Orthogonal Frequency Division Multiple, OQAM-OFDM) utilizes filtering with good time-frequency focusing characteristics The device g...

AI Technical Summary

Problems solved by technology

[0006] To sum up, although OQAM-OFDM uses filter banks to counteract the dispersion and nonlinear effects of optical fiber channels and reduce the sensitivity to frequency offset and phase noise, it uses a series of derivatives whose values ​​are fixed at +1 and -1. The frequency sequence does not deal well with the ISI and ICI caused by the subcarrier orthogonality destruction, even without signal distortion and noise introduction, it cannot accurately estimate the true value of the channel

Moreover, when most algorithms compensate for signal distortion caused by fiber dispersion and nonlinear effects, they often ignore the problem of randomly distributed Gaussian noise caused by system components, which directly affects the receiving sensitivity of the system

Images