Communication systems have the challenge of accommodating many users in a small area. With the advent of spread spectrum, and hence, Code Division Multiple Access (CDMA), fixed bandwidth was used to accommodate many users by making use of certain coding properties, modulation techniques and optimization algorithms. The aim of this paper is to explore the concept of Genetic Algorithm (GA) for CDMA-based Multi-User Detection (MUD) system model in multipath Rayleigh fading environment. MUD is the intelligent estimation/demodulation of transmitted bits in the presence of Multiple Access Interference (MAI). MAI occurs in multi-access communication systems (CDMA/TDMA/FDMA), where simultaneously occurring digital streams of information interfere with each other. Compared with other algorithms, GA provides better performance, and therefore, can be believed to be the next generation algorithm for the optimization problem. The proof of the statement is explored by analyzing and comparing simulated results for different number of users, modulation techniques and spreading codes under the effect of Rayleigh fading channel. Bit Error Rate (BER) and time profile are the measures of performance in this research document.

One of the key problems in Code Division Multiple Access (CDMA) systems is the detrimental effect of Multiple User Interface (MAI) to the performance of the receivers and the overall communication system (Kai and Lajos, 2004). The problem is particularly severe in mobile communications. Multi-User Detection (MUD) techniques can be used to alleviate the performance degradations due to MAI.

In the context of CDMA multiuser detection, the three most important criteria to be satisfied by an efficient detection scheme are its Bit Error Rate (BER) performance, detection time and computational complexity.

There are many algorithms in practice such as Minimum Mean Square Error (MMSE), Zero Forcing (ZF), and Probabilistic Data Association (PDA), and techniques like MIMO V-BLAST, etc. Genetic Algorithm (GA) is one such algorithm which can be employed for Multi-User Detection (MUD). This paper provides a simple model for investigating the feasibility of applying GAs in CDMA multiuser detection, as well as for determining the configuration of GAs, in order to obtain a satisfactory performance in terms of BER and time.

Telecommunications Journal, Genetic Algorithm, Code Division Multiple Access, CDMA, Genetic Algorithm, GA, Multi-User Detection, MUD, Multiple Access Interference, MAI, Arbitrary Decision Variables, Rayleigh Fading Environment, Bit Error Rate, BER, Probabilistic Data Association, PDA, Modulation Techniques.