Subcarrier modulation-based OQAM-OFDM wavelength stack PON downlink transmission system

Abstract

The invention provides a subcarrier modulation-based OQAM-OFDM wavelength stack PON downlink transmission system. Based on subcarrier modulation, a DSB-SC module generates an optical subcarrier required for subcarrier modulation. That is, a single laser provides an optical carrier for two downlink radio frequency OQAM-OFDM signals. In this way, the utilization rate of resources is improved and the cost of an access network system is lowered. OQAM-OFDM modulation signals are high in sidelobe suppression ratio and spectral efficiency and can relax the ICI interference and the ISI interference. Based on the comprehensive utilization of the above advantages of the OQAM-OFDM modulation signals, the downlink signal transmission of narrower subcarrier interval is realized. Meanwhile, the bandwidth utilization ratio is improved and the access number of users is increased. Based on the flexible deployment of the system, the long-distance heterodyne coherent detection on OQAM-OFDM signals can be realized through the direct detection of a photoelectric detector.

Description

technical field [0001] The present invention relates to the technical field of optical communication, in particular to an OQAM-OFDM wavelength stacking PON downlink transmission system based on subcarrier modulation. Background technique [0002] In recent years, Internet traffic and bandwidth requirements have grown exponentially. According to a recent Cisco report, the "last mile" traffic will exceed long-distance transmission traffic in 2015, and the bandwidth bottleneck will be greatly shifted to the "last mile". Passive optical network (PON) has become one of the most promising access network technologies because of its high capacity and low cost. However, the existing EPON / GPON technologies are difficult to meet the increasing demand for bandwidth, and the existing commercial PON structure often adopts OOK modulation and detection due to the consideration of simplicity and low cost. In order to improve the data transmission rate and bandwidth capacity, the industry ha...

AI Technical Summary

Problems solved by technology

However, the subcarrier generation method used in this system requires a high-frequency radio frequency clock source, which increases the system cost; and based on single-wavelength OFDM-PON direct detection, the high sidelobe of the OFDM signal and the system guard sideband reservation will cause spectrum The utilization rate is reduced; in addition, the use of polarization multiplexing technology based on direct detection requires improvement of the traditional polarization demultiplexing method and the corresponding coherent demodulation technology, which increases the complexity and cost of the ONU demodulation module

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