Title :
Optical orthogonal codes with large crosscorrelation and their performance bound for asynchronous optical CDMA systems
Author :
Weng, Chi-Shun ; Wu, Jingshown
Author_Institution :
Dept. of Electr. Eng., Nat. Taiwan Univ., Taipei, Taiwan
fDate :
3/1/2003 12:00:00 AM
Abstract :
Optical orthogonal codes (OOCs) are commonly used as signature codes for optical code-division multiple-access (OCDMA) communication systems. Many OOCs have been proposed and investigated. Asynchronous OCDMA systems using conventional OOCs have a very limited number of subscribers and few simultaneous users. Recently, we reported a new code family with large code size by relaxing the crosscorrelation constraint to 2. In this paper, by further loosening the crosscorrelation constraint, we adopt the random greedy algorithm to construct a code family which has larger code size and more simultaneous users. We also derive an upper bound of the number of simultaneous users for a given code length, code weight, and bit error rate. The study shows that it is possible to have codes approaching this bound.
Keywords :
code division multiple access; codes; error statistics; multiuser channels; optical correlation; optical fibre networks; asynchronous optical CDMA systems; bit error rate; code length; code weight; large code size; large crosscorrelation; multiuser interference; optical orthogonal codes; perfect difference code; performance bound; random greedy algorithm; signature codes; simultaneous users; Autocorrelation; Bit error rate; Councils; Greedy algorithms; Multiaccess communication; Multiple access interference; Optical receivers; Robustness; Upper bound;
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2003.809547
