基于远程差频检测的波分复用OFDM-PON关键技术的研究

Recently, the giant boost of the access network applications such as triple play and broadband services has pushed the capacity of existing Passive Optical Network (PON) to its limit. In order to meet the demands of large bandwith, high bitrate , long reach transmission, etc, a novel access architecture named RHDWDM-OFDM-PON (Remote Heterodyne Detection Wavelength Division Multiplexing-Orthogonal Frequency Division Multiplexing- Passive Optical Network) is proposed in this project. In this system, OFDM technique is combined with the WDM to increase the transmission capacity. Remote Heterodyne and Self Homodyne schemes are utilized in downstream and upstream detection respectively, so that the receiver sensitivity of both transmission directions can be significantly increased. .The critical technologies adopted in this project are showed as follows. For downsteam transmission, transmitter based on Double-SideBand Suppressed Carrier (DSB-SC) generation mechanism is utilized at Optical Line Terminal (OLT) in order to provide the double light source for Remote Heterodyne detection at Optical Network Unit (ONU). In upstream direction, multi-wavelength shared scheme based on single polarization light injection locking technique is proposed to eliminate the laser source in ONU. Chirp and dispersion suppression technique is employed at OLT. Self homodyne coherent receiver is also designed. Moreover, at Media Acess Control (MAC) layer, multiple granularity allocation schemes are raised for the efficient usage of network resources including wavelengths, time slots, subcarriers and transmission levels. .Due to the advantages of high transmission rate, long-reach distance and low cost, the RHDWDM-OFDM-PON proposed in this project can be viewed as a highly attractive candidate for the next generation optical access network.

为顺应三网融合加快、接入网服务扩展的趋势，满足用户对大容量、高速率及长距离信息传送的需求，本项目提出一种基于远程差频检测的波分复用OFDM-PON(正交频分复用无源光网络)"RHDWDM-OFDM-PON"。系统采用OFDM和WDM复用方式增大传输容量，采用差频检测增加传输距离。下行方向为外差检测，上行方向为自零差检测，设计了相应的载波抑制双光源产生方式、单偏振光注入锁定的多波长共享机制和直调激光器的啁啾与色散抑制方案以及自零差相干接收机，使网络中的上下行接收灵敏度和数据速率都可以得到极大提高。提出了新颖的多粒度资源调度方式，能够有效地分配波长、时隙、子载波和传输电平数，提高网络资源利用率。本项目将在已开展的PON相关技术研究基础上，探索和验证RHDWDM-OFDM-PON 的关键技术，发展一种传输速率高、覆盖范围大且成本较低的接入网解决方案，推动下一代新型光接入网技术的研发和应用。

为顺应三网融合加快、接入网服务扩展的趋势，满足用户对大容量、高速率及长距离信息传送的需求，本项目提出并研究了一种基于远程差频检测的波分复用OFDM-PON (正交频分复用无源光网络)即RHDWDM-OFDM-PON。系统采用OFDM和WDM复用方式增大了传输容量，采用差频检测技术增加了传输距离。完成的研究工作主要涉及以下四个方面。. 1）上行传输关键技术。首次提出并验证了基于通用滤波化多载波技术（UFMC）和交错正交幅度调制OFDM (OQAM-OFDM) 的两种多带上行异步传输方案；关于光信号接收，提出了基于频域平均的信道估计算法和基于M序列的定时同步算法，实现了接收端OFDM信号的正确解调；为了提升系统性能和降低成本，提出了基于延时干涉仪DI、可调谐滤波器TOF的两种直调激光器啁啾管理技术和基于级联SOA、级联RSOA的两种无色化ONU技术，并进行了实验验证。. 2）下行传输关键技术。提出并验证了一种基于DSP的多速率共存、自适应调节的传输方案；关于光信号接收，提出了基于sign-MCMA的盲均衡信道估计算法和基于训练序列的IQ不平衡补偿算法，实现了远端OFDM信号的光外差检测和正确解调；为提升接收信号质量，提出并验证了一种基于电吸收调制器EAM的后向瑞利噪声抑制技术；研究了入纤光功率、激光器线宽和光纤色散对直接检测/外差检测系统性能的影响，优化了系统性能降低了系统成本。. 3）资源共享的调度机制。研究了子载波/时隙联合调度模型，提出并仿真验证了最短请求优先调度SRF和贪婪调度GSA这两种资源调度算法。. 4）RHDWDM-OFDM-PON系统实验。4波长单路速率10Gb/s 的系统在传输距离为25km、50km、75km 和100km时，可支持的ONU数量分别为1024、1024、256和64；4波长单路速率25Gb/s的系统最大传输距离可达40km，在25km传输时可支持1024个ONU；在远程外差检测模式下，2波长单路速率25Gb/s的系统可实现480km无误码传输。