New Methods to Analyze Bounds of OOC for OCDMA System Based on Optical Code-hoop

摘要

Having excellent quality of correlation and large number of cardinality, optical orthogonal code has become one of the main signature codes for OCDMA system. The main goals of OOC designing are to make MUI as little as possible and cardinality as large as possible. The paper has designed a device standing for OOC, optical code-hoop, which can be used easily to check the correlation of code family. Code-hoop can replace code-pattern made by Salehi, which can only check correlation between two special codes one time. The hoop can check the correlations between all codes in the family at one time. More importantly, based on the code-hoop, the upper bound of code cardinality be acquired from code family itself the code-hoop, instead of introducing Johnson bound of error-correcting code to OCDMA system. In the article, the upper bounds of cardinalities of symmetric, constant-weight OOC (L,w,1) and (L,w,λ) are an-alyzed in detail, and the results are concordant with introducing Johnson bound.