An embedded transmission scheme using PPM signaling with symmetric error-correcting codes for optical CDMA
An embedded transmission scheme using PPM signaling with symmetric error-correcting codes for optical CDMA
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一种使用带有对称纠错码的 PPM 信令的光 CDMA 嵌入式传输方案
DOI：
10.1109/jlt.2003.814387
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发表时间：
2003
影响因子：
4.7
通讯作者：
K. Yashiro
中科院分区：
文献类型：
--
作者：
K. Kamakura;K. Yashiro
提出了一种嵌入式传输（ET）方案，可以很容易地将纠错码应用到光码分多址（CDMA）系统中，以抵抗多址干扰（MAI）。ET方案提供了比使用脉冲位置调制（PPM）信令的传统方案更高的传输能力，因为每个用户的2/sup J/-进制符号被嵌入到具有2/sup J/加权位置的签名序列中。此外，具有2/sup J/-进制PPM信令的ET方案使得光CDMA系统成为J个并行传输系统，因为由2/sup J/-进制符号组成的J个比特被单独决定。由于这种单独的判定是比较判定，所以在光信道中添加的MAI的影响被转换为各个并行传输系统中的对称误差。使用对称纠错（SEC）码比中描述的嵌入调制方案更容易使各个并行传输系统免于MAI，因为ET方案避免使用难以实现的非对称纠错码。分析了泊松光子计数信道下的误码率，表明在SEC码的应用中，ET方案比传统方案具有更好的能量效率。
An embedded transmission (ET) scheme is proposed to easily apply error-correcting codes into optical code-division multiple-access (CDMA) systems for immunity from multiple-access interference (MAI). The ET scheme offers high transmission capability over the traditional scheme using pulse position modulation (PPM) signaling, because a 2/sup J/-ary symbol of each user is embedded in the signature sequence with 2/sup J/ weighted positions. Furthermore, the ET scheme with 2/sup J/-ary PPM signaling makes the optical CDMA system J parallel transmission systems, because J bits consisting of 2/sup J/-ary symbol are separately decided. Since such a separate decision is a comparison decision, the effect of MAI added in the optical channel is converted to symmetric errors in the individual parallel transmission systems. Using the symmetric error-correcting (SEC) code immunizes the individual parallel transmission systems against MAI more easily than the embedded-modulation scheme described in because the ET scheme avoids using the asymmetric error correcting code, which is difficult to implement. We analyze the bit error rate under Poisson photon counting channel and show that the ET scheme has an advantage of good energy efficiency over the traditional scheme in applying SEC codes.