二维变权光正交码的新构造法优化高速OCDMA网络
197 浏览量
更新于2024-08-27
收藏 226KB PDF 举报
本文主要探讨了在高速光时分复用（Optical Code-Division Multiple Access, OCDMA）网络中构建最优的二维变重量光正交码（Two-Dimensional Variable-Weight Optical Orthogonal Codes, 2D VWOOCs）的设计方法。针对支持多服务质量（Quality of Service, QoS）的高速网络环境，作者提出了一种新型的编码构造策略，着重强调了这些代码具有每个波长最多一个脉冲（Amplitude Modulation - One Pulse Per Wavelength, AM-OPPW）的特性。这一特性对于减少信号间的干扰和提高数据传输效率至关重要。
研究者推导出了一种关于具有AM-OPPW特性的2D VWOOCs的码字基数上限，这为评估和优化网络性能提供了理论依据。文章的核心贡献在于证明了所构造的2D VWOOCs不仅具有理想的互相关性质，即码字之间的相互影响最小，而且在码字基数上达到了最优状态。这意味着这些编码方案能够提供高效的数据传输同时保持良好的纠错能力和系统可靠性。
此外，文中对所提出的编码方案与现有编码技术在码长和误码率（Bit Error Rate, BER）方面的性能进行了对比分析。通过这样的对比，读者可以了解新方法在实际应用中的优势，尤其是在竞争激烈的高速OCDMA网络环境中，优化的2D VWOOCs能够提供更高的数据速率和更低的错误概率，从而显著提升网络的整体性能和用户体验。
总结来说，这项研究对于提升高斯OCDMA网络的容量、效率和服务质量具有重要意义，为设计和实现未来高效、灵活的光通信系统提供了重要的理论支持和技术指导。
884 CHINESE OPTICS LETTERS / Vol. 8, No. 9 / September 10, 2010
Construction of optimal 2D variable-weight optical
orthogonal codes for high-speed OCDMA networks
Xiyang Li (
)
1,2∗
, Pingzhi Fan (
)
1
, andXianfuLei(
)
1
1
Provincial Key Lab of Information Coding & Transmission, School of Information Science & Technology,
Southwest Jiaotong University, Chengdu 610031, China
2
School of Mathematical Sciences, Guangxi Teachers Education University, Nanning 530023, China
∗
E-mail: xyli13@163.com
Received June 1, 2010
A new construction method of two-dimensional (2D) variable-weight optical orthogonal codes (VWOOCs)
is proposed for high-speed optical code-division multiple-access (OCDMA) networks supporting multiple
qualities of services (QoS). The proposed codes have at most one-pulse per wavelength (AM-OPPW)
property. An upper bound of the codeword cardinality of the 2D VWOOCs with AM-OPPW property
is derived. It is then shown that the constructed codes have ideal correlation properties and optimal
cardinality. Moreover, the code length and the bit-error-rate (BER) performance of the proposed codes
are compared with those of the codes proposed previously.
OCIS codes: 060.1155, 060.2360, 060.4230.
doi: 10.3788/COL20100809.0884.
Optical code-division multiple-access (OCDMA) tech-
nique has gained significant attention in optical com-
munication networks due to its potential for simplicity
in all-optical implementation, inherent security against
interception, and asynchronous access
[1,2]
. The user ad-
dress code with better performance, such as optical or-
thogonal code (OOC)
[1,3,4]
, is the basis for the implemen-
tation of an OCDMA network.
Recently, there are more requirements on the high-
speed OCDMA system supporting multiple qualities of
services (QoS). One-dimensional (1D) variable- weight
(VW) OOCs were proposed by Yang
[5]
for this pur-
pose. Due to the unipolar characteristic of optical sig-
nals, 1D optical codes
[5−7]
are always very long so that
they reduce multiple-access interference (MAI) and in-
crease the codeword cardinality. To overcome this draw-
back, much attention has been paid to two-dimensional
(2D) VWOOCs recently
[8−11]
. The 2D optical en-
coder/decoder can be realized by fiber Bragg gratings
(FBGs)
[12,13]
. However, due to the use of 1D VWOOCs
as time spreading patterns in the 2D VWOOCs
[8−11]
,the
code length will also be large and thus the data rate will
decrease. Therefore, codes with shorter lengths than that
of previous codes
[8−11]
need to be constructed to meet the
requirements of high-speed multimedia transmissions.
To simplify practical implementation and provide scal-
ability to OCDMA networks
[3,11]
, 2D VWOOCs with
at most one-pulse per wavelength (AM-OPPW)
[3]
prop-
erty were proposed recently by Piao et al.
[11]
based
on the combinatorial method and computer searching.
The codes have ideal correlation properties, i.e., maxi-
mum out-of-phase autocorrelation equal to 0 and cross-
correlation equal to 1. An upper bound of the codeword
cardinality was also derived
[11]
. However, the set of code-
word cardinality distributions was not considered
[11]
.
In this letter, a new construction method of 2D
VWOOCs with AM-OPPW property is proposed for
high-speed OCDMA networks. An upper bound of the
codeword cardinality is derived to show the optimality of
the presented construction. It is also shown that the con-
structed codes have ideal correlation properties. More-
over, the code length and the bit-error-rate (BER) per-
formance of the proposed codes are compared with those
of the codes proposed previously.
Throughout this letter, let W ,Λ,andQ denote the sets
{w
1
,w
2
, ··· ,w
l
}, {λ
1
a
,λ
2
a
, ··· ,λ
l
a
},and{q
1
,q
2
, ··· ,q
l
},
respectively. Without loss of generality, we assume that
w
1
≤ w
2
≤ ··· ≤ w
l
.LetZ
n
= {0, 1, ··· ,n− 1} denote
the group of residues modulo n. |A| indicates the cardi-
nality of a set A.
A2D(u× v, W, Λ,λ
c
,Q)-VWOOC, C, is a collection of
binary (0,1) u × v code matrices (codewords) such that
the following three properties hold.
1) Weight distribution: each codeword in C has a Ham-
ming weight contained in the set W ; furthermore, there
are exactly q
k
·|C| codewords of weight w
k
, i.e., q
k
indi-
cates the fraction of codewords of weight w
k
.
2) Auto-correlation: for any X =(x
i,j
) ∈ C with Ham-
ming weight w
k
∈ W and any integer τ, 0 <τ ≤ v − 1,
R
X,X
(τ)=
u−1
i=0
v−1
j=0
x
i,j
x
i,j+τ
≤ λ
k
a
. (1)
3) Cross-correlation: for any X =(x
i,j
), Y =(y
i,j
) ∈
C such that X = Y and any integer τ,
R
X,Y
(τ)=
u−1
i=0
v−1
j=0
x
i,j
y
i,j+τ
≤ λ
c
. (2)
All subscripts here are reduced modulo v so that pe-
riodic correlations are considered. In the following, the
notation (u × v, W, 0, 1,Q)-VWOOC is used to denote an
(u × v, W,Λ,λ
c
,Q)-VWOOC with ideal correlation prop-
erties, i.e., λ
1
a
= λ
2
a
= ···= λ
l
a
=0andλ
c
=1.
Let X be a code matrix of a (u × v, W,Λ,λ
c
,Q)-
VWOOC with weight w and some integers r
i
∈ Z
u
,
c
i
∈ Z
v
such that x
r
0
,c
0
= x
r
1
,c
1
= ··· = x
r
w−1
,c
w−1
=
1, where 0 ≤ r
0
≤ r
1
≤ ··· ≤ r
w− 1
≤ u − 1.
The fact that x
r
i
,c
i
= 1 means an optical pulse of
1671-7694/2010/090884-04
c
2010 Chinese Optics Letters
下载后可阅读完整内容，剩余3页未读，立即下载
2019-08-26 上传
2020-09-13 上传
2021-02-08 上传
2021-02-10 上传
2021-04-22 上传
2021-05-28 上传
2021-04-28 上传
2016-01-26 上传
2021-03-05 上传
代码加烟，法力无边
- 粉丝: 183
- 资源: 902
我的内容管理
展开
最新资源
- Android圆角进度条控件的设计与应用
- mui框架实现带侧边栏的响应式布局
- Android仿知乎横线直线进度条实现教程
- SSM选课系统实现：Spring+SpringMVC+MyBatis源码剖析
- 使用JavaScript开发的流星待办事项应用
- Google Code Jam 2015竞赛回顾与Java编程实践
- Angular 2与NW.js集成：通过Webpack和Gulp构建环境详解
- OneDayTripPlanner：数字化城市旅游活动规划助手
- TinySTM 轻量级原子操作库的详细介绍与安装指南
- 模拟PHP序列化:JavaScript实现序列化与反序列化技术
- ***进销存系统全面功能介绍与开发指南
- 掌握Clojure命名空间的正确重新加载技巧
- 免费获取VMD模态分解Matlab源代码与案例数据
- BuglyEasyToUnity最新更新优化：简化Unity开发者接入流程
- Android学生俱乐部项目任务2解析与实践
- 掌握Elixir语言构建高效分布式网络爬虫
