Construction and performance analysis of new codes for optical CDMA networks with M-ary signaling

• Main Authors: Kung-Tien Lee, 李耿典
• Other Authors: Jyh-Horng Wen
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/67473600976189244194

碩士 === 國立中正大學 === 通訊工程研究所 === 89 === In this thesis we investigate the construction of spreading code for optical CDMA systems. Because the characteristic of the electric and optical signal is different, e.g., the optical signal is positive and the electric signal may be positive or negative, the spreading code used in RF-CDMA systems is inappropriate to use in optical CDMA systems. The low noise property is an advantage in optical communications. Therefore, we don’t consider the effect of noise on the performance of our proposed systems. The main performance degradation is caused by the multiple access interference only. In this thesis we propose two new code constructions and analyze the performance for Direct Sequence (DS)-CDMA system and Fast Frequency Hopping (FFH) CDMA system respectively. Conventionally, the spreading codes for optical CDMA system encode one bit per symbol. However, both of our proposed new codes can encode k bits per symbol. Therefore, the transmission rate can be increased by k times with the new codes. Based on the performance analysis, we get the expected result that the BER of our proposed system is better than the conventional one.