Design and Performance Analysis of an OCDMA System with Pulse Position Modulation

• Main Authors: Yi-Siang Kao, 高翊翔
• Other Authors: Po-Hao Chang
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/79959250870502714566

碩士 === 國立東華大學 === 電機工程學系 === 99 === CDMA techniques can be implemented directly in the optical domain based on ultrashort optical pulse laser sources. The techniques can be used as an additional optical layer of multiplexing hierarchy based on WDMA and allow electrical user signal access to the optical network in a more natural way. And it is worthy of further investigation in the goal of realizing an extensive, high capacity and easily managed optical telecommunication infrastructure. We analyze the capacity of the optical spread-time code-division multiple-access system with M-ary Pulse Position Modulation (PPM). Optical spectral phase codes are used as the signature sequences in our system. Considering the multi-access interference (MAI) at the same received power, we derive the union upper bound on the bit error rate. As a result, we compare the system bit error rate performance for the OOK OCDMA system and for the PPM OCDMA system. We improve the performance dramatically by increasing code length. Finally, we also promote the capacity of PPM OCDMA system.