大容量灵活低成本实时OFDM-PON系统下行传输方案及关键技术研究

The existing PON system has many problems, such as low spectrum efficiency, inflexible bandwidth allocation and high cost. OFDM has the advantages of high spectrum efficiency, flexible bandwidth allocation and good anti-dispersion performance. However, due to technical complexity and cost, it is not adopted by the latest PON standard. Most of the existing OFDM research results are based on offline analysis, and do not take into account a series of problems such as complexity, accuracy and resource cost in the transceiver hardware implementation process, which limits its practicality. This project is oriented to real-time PON downlink transmission scenarios. Guided by improving single wavelength transmission rate, reducing algorithm complexity and system cost, the work is carried out in three aspects: (1) Overall design and optimization of large capacity, flexible and low-cost real-time PON downlink transmission scheme. (2) Research and implementation of key technologies such as reducing sampling rate, PAPR and logical resource overhead in high-speed real-time system. (3) Establish simulation and experimental platforms to verify the effectiveness of the transmission scheme and key technologies. The expected achievements will further promote the development of OFDM-PON system and provide strong theoretical and technical support for it in the competition of PON standards in the future, and support the development of the next generation of large capacity and wide coverage fiber access network.

现有PON系统存在频谱效率低、带宽分配不灵活、成本高等问题，难以满足未来高速率、广覆盖PON的需求。OFDM具有频谱效率高、带宽分配灵活、抗色散性能好等优点，但由于技术复杂度和成本等原因没有被最新的PON标准采纳。现有OFDM研究仍以离线分析为主，没有考虑收发机硬件实现过程中复杂度、精度、资源开销等问题，限制了其走向实用化。本项目面向实时PON系统下行传输场景，以提高单波长传输速率，降低算法复杂度和系统成本为指引，具体在三个方面展开工作：（1）大容量、灵活、低成本的高速实时PON系统下行传输方案的全面设计和优化；（2）高速实时系统中降低采样率、PAPR及逻辑资源开销等关键技术的研究与实现；（3）建立仿真和实验平台，验证传输方案和关键技术的有效性。预期成果将进一步推动OFDM-PON系统的发展，为其在未来PON标准竞争中提供有力的理论和技术支持，支撑下一代大容量、广覆盖光纤接入网络的发展。

针对现有PON系统存在的频谱效率低、带宽分配不灵活、成本高等问题，本项目基于OFDM具有的频谱效率高、带宽分配灵活、抗色散性能好等优点，研究了大容量灵活低成本的OFDM-PON下行传输系统，旨在提高OFDM-PON系统在实际工程中的应用价值。已完成的研究内容可归纳成以下四部分：①设计实现了一种大容量、高频谱效率、带宽分配灵活、低成本的实时下行传输方案；②提出并实现了上下变频和欠采样的方法，解决了ONU端ADC采样率过高的问题，可有效降低接收端的系统成本；③研究并解决了OFDM固有的高PAPR的问题，可有效提高信号的非线性容忍度；④研究并实现了多种单载波多偏振态调制解调方法，可进一步提高信号的频谱效率和系统容量；本项目研究成果可进一步推动OFDM-PON系统的发展，支撑下一代大容量、广覆盖光纤接入网络的发展，为其工程应用奠定坚实的理论基础和技术储备。