Effective design of optical fiber code-division multiple access networks using the modified prime codes and optical processing

In optical fiber code-division multiple access (CDMA) networks using the well-known prime code, the code weight w is always fixed to the maximum number of users N (i.e., the code size). When N becomes very large, the resulting cost and optical power losses of the optical CDMA encoder/decoder can be very high. To overcome this difficulty, an efficient design is presented for optical fiber CDMA networks, which is based on the modified prime (MPR) codes. The use of MPR codes can maintain the fixed w for a given bit error rate and any N, while MPR codes still preserve the same cross-correlation constraint (i.e., two) as the original prime codes. Furthermore, the code-design procedure described in this paper can be easily used to construct variable length and nonconstant-weight MPR codes as well as 2ⁿ-MPR codes