Design of multiweight unipolar codes for multimedia optical CDMA applications based on pairwise balanced designs

A novel class of constant-length variable-weight optical orthogonal codes is proposed that can support multimedia services with different data rates and quality-of-service requirements. The construction is based on the pairwise balanced designs, or more specifically, on an incidence structure defined on an integer lattice. Proposed codes are suitable for spectral-amplitude coding, fast-frequency hopping, and time-spreading encoding in multimedia environment. A novel dual-balanced decoder is proposed capable of canceling multiuser interference in multimedia applications for spectral-amplitude-coding schemes employing the unipolar codes having nonfixed in-phase cross correlation.