RIA: All-Optical Code Division Multiple-Access Communication Systems

9409452勃兰特-皮尔斯光自由空间或光纤通信网络理论上可以支持每秒几太比特的总信息吞吐量。提出了多用户光学系统设计的几种可能性，从而有效地利用了带宽。码分多址(码分多址)技术以其灵活、高效的特点被选为多路复用方案。本研究的重点是相干检测和非相干检测光码分多址的全光调制解调技术的设计和后续分析。如果要保持总体的码分多址扩展增益和用户数据速率不受限制，则必须光学地实现码元检测器。传统的光码分多址系统由于其较差的符号检测算法(相关检测器)，其吞吐量极限比理论极限低几个数量级。首先，提出了几种基于全光处理的非相干(直接检测)系统的替代检测算法，它们在不增加硬件复杂度的情况下提高了吞吐量和性能。然后针对相干(外差)检测光学系统提出了几种多用户检测算法。对宽带码分多址信号进行光学处理，然后采用电子码元判决算法。利用大偏差理论、矩空间界限和重要抽样仿真对误码率进行了近似。***

9409452 Brandt-Pearce An optical free-space or fiber communications network can theoretically support several terabits per second total information throughput. Several possibilities of design of multi-user optical systems are proposed such that the bandwidth is utilized efficiently. Code-division multiple-access (CDMA) has been chosen as the multiplexing scheme due to its flexibility and efficiency. The thrust of this research is the design and subsequent analysis of all-optical modulation and demodulation techniques for coherent detection and incoherent detection optical CDMA. A symbol detector must be implemented optically if the overall CDMA spreading gain and user data-rate is to remain unrestricted. The conventional optical CDMA system suffers a through-put limit orders of magnitude lower than the theoretical limit due to its poor symbol detection algorithm (the correlation detector). First, several alternative detection algorithms relying on all-optical processing for an incoherent (direct-detection) system are proposed that improve the throughput and performance without imposing an excessive hardware complexity. Then several multi-user detection algorithms are proposed for a coherent (heterodyne) detection optical system. Optical processing is used on the broadband CDMA signal, followed by an electronic symbol decision algorithm. The bit-error probability is approximated by using large deviations theory, moment space bounds, and importance sampling simulations. ***