Flexible optical fiber CDMA networks using strict opticalorthogonal codes for multimedia broadcasting and distributionapplications

摘要

Flexible optical fiber code-division multiple-access (CDMA) networks are proposed to support real-time multimedia communication services of constant bit rate (CBR) and variable bit rate (VBR)/multiple bit rate (MBR). Since strict optical orthogonal codes (OOCs) are employed in incoherent optical fiber CDMA networks, their use can strictly guarantee the correlation constraint λ to be the minimum value (i.e., an unit “1”) for multimedia applications. This is achieved without increasing any system complexity compared with the use of conventional OOCs. Moreover, optimal strict OOCs can have the same length as optimal conventional OOCs or a slightly longer length than the latter. It is shown that the proposed optical fiber CDMA networks have a distinguishing feature of high bit-rate flexibility and fast access tunability. Consequently, this can effectively support both VBR and CBR video communications as well as multimedia broadcasting/distributions in a given network without any violation of the minimum correlation constraint λ=1. The proposed network can be also used as a backbone to interconnect various local-area networks with different data bit rates. However, conventional OOC-based optical CDMA networks do not possess such characteristics because of violation of λ=1 for VBR or MBR communications