SVM for Constellation Shaped 8QAM PON System
LI Zhongya1, CHEN Rui1, HUANG Xingang2,ZHANG Junwen1, NIU Wenqing1, LU Qiuyi1, CHI Nan1
(1. Key Laboratory for Information Science of Electromagnetic Waves, Fudan University, Shanghai 200433, China;
2. ZTE Corporation, Shanghai 201203, China)
Abstract: Nonlinearity impairments and distortions have been bothering the bandwidth constrained passive optical network (PON) system for a long time and limiting the development of capacity in the PON system. Unlike other works concentrating on the exploration of the complex equalization algorithm, we investigate the potential of constellation shaping joint support vector machine (SVM) classification scheme. At the transmitter side, the 8 quadrature amplitude modulation (8QAM) constellation is shaped into three designs to mitigate the influence of noise and distortions in the PON channel. On the receiver side, simple multi-class linear SVM classifiers are utilized to replace complex equalization methods. Simulation results show that with the bandwidth of 25 GHz and overall bitrate of 50 Gbit/s, at 10 dBm input optical power of a 20 km standard single mode fiber (SSMF), and under a hard-decision forward error correction (FEC) threshold, transmission can be realized by employing Circular (4, 4) shaped 8QAM joint SVM classifier at the maximal power budget of 37.5 dB.
Keywords: passive optical networks; support vector machine; geometrically shaping, constellation classification, digital signal processing