Design and performance analysis of code families for multi-dimensional optical CDMA

A code design algorithm for application in Multi-Dimensional Optical Code Division Multiple Access (MD-OCDMA) for asynchronous optical fibre communication is proposed. Two-dimensional (2-D) wavelength-time or space-time OCDMA and three-dimensional (3-D) space-wavelength-time OCDMA are subsets of MD-OCDMA. Some applications and the performance analysis of the algorithm in 2-D multipulse per row codes and 3-D multipulse per plane codes are shown. In the applications discussed, this design ensures a maximum crosscorrelation of ‘1’ between any two codes. The performance metrics studied are the probability of error due to multiple access interference for different numbers of 1 active users and optimum temporal length for different values of cardinality. The performance analysis shows that the proposed 2-D design offers very low probability of error due to multiple access interference at lower cardinality when compared with other 2-D designs using equivalent code dimension. A comparison of the proposed 3-D design with an existing 3-D design shows better performance at lower cardinality. The 3-D designs show better performance when compared with the 2-D designs.