Passive optical fast frequency-hop CDMA communications system
Passive optical fast frequency-hop CDMA communications system
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DOI：
10.1109/50.749379
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发表时间：
1999-03-01
影响因子：
4.7
通讯作者：
LaRochelle, S
中科院分区：
文献类型：
--
作者：
Fathallah, H;Rusch, LA;LaRochelle, S
提出了一种适用于高带宽通信的全光纤快速光跳频码分多址（FFH-CDMA）系统。该系统不需要光频率合成器，通信速率高，编码和解码均由应变可调谐光纤光栅实现。多个布拉格光栅取代一个频率合成器，实现了几十GHz的跳频速率，在写入光栅时可以采用主瓣正弦切趾，提高了系统容量和频谱效率，所有网络用户可以使用相同的可调谐编/解码器设计。时域和频域的同时利用提供了显着的灵活性，在代码的选择，仿真结果表明，编码器有效地执行FFH扩频信号的生成，接收机很容易提取所需的信号从接收信号的几个多址干扰的情况。我们衡量系统的误码率，以及自相关的对比度方面的性能。在具有多达30个同时用户且误码率为10（-9）的系统中，支持每用户500 Mb/s的传输速率。我们比较FFH-CDMA几个直接序列CDMA系统的误比特率与并发用户数。我们表明，光学FFH-CDMA系统需要新的码族设计标准，因为光学器件技术与射频通信技术有显着不同。
This paper proposes an all-fiber fast optical frequency-hop code division multiple access (FFH-CDMA) for high-bandwidth communications. The system does not require an optical frequency synthesizer, allowing high communication bit rates, Encoding and decoding are passively achieved by strain-tunable fiber Bragg gratings. Multiple Bragg gratings replace a frequency synthesizer, achieving a hopping rate in tens of GHz, A main lobe sine apodization can be used in writing the gratings to enhance the system capacity and the spectrum efficiency, All network users can use the same tunable encoder/decoder design. The simultaneous utilization of the time and frequency domains offers notable flexibility in code selection, Simulations show that the encoder efficiently performs the FFH spread spectrum signal generation and that the receiver easily extracts the desired signal from a received signal for several multiple access interference scenarios. We measure the system performance in terms of bit error rate, as well as auto-to cross-correlation contrast. A transmission rate of 500 Mb/s per user is supported in a system with up to 30 simultaneous users at 10(-9) bit error rate. We compare FFH-CDMA to several direct sequence-CDMA systems in terms of bit error rate versus the number of simultaneous users. We show that an optical FFH-CDMA system requires new design criteria for code families, as optical device technology differs significantly from that of radio frequency communications.