STBC MC - CDMA with Genetic Algorithm Based MUD for Wireless Multimedia Communications

Optimum detection for a direct sequence code-division multiple-access (DS-CDMA) system using conventional MUD is known to have a high computational complexity. For K number of users for instance, the computational complexity grows exponentially with K. The impact of this complexity problem is more serious for the more complicated variants of CDMA such as space time block coded (STBC) multi-carrier code-division multiple-access (MC-CDMA), since the processing of the received signal in this system requires more complex methods than that of DS- CDMA. Although suboptimum detection methods with less complexity are available, they are less powerful than MUD. To achieve the optimality of MUD while avoiding the computational complexity, we designed a binary genetic algorithm based MUD. For the evaluation, we simulated STBC MC-CDMA system over a frequency selective rayleigh fading channel. For the purpose of comparison, STBC MC-CDMA receiver using equal gain combining (EGC) was simulated as well. All systems were given an image input, whereby the received images shows that the system of interest has significantly better quality while maintaining reasonable computational complexity.