Review of Different Optimization Techniques used for Multi-User Detection in CDMA Network

Code Division Multiple Access is a methodology used by varied communication technologies like wireless communication, radio technology etc. it's a kind of multiplexing, that permits various signals to occupy one transmission channel, optimizing the use of available bandwidth. Different signals have different codes in this. However, generally because of a large number of users, interference results between them which leads to increased bit error rate and also near far problem. Optimization has played a very important role in finding a solution to this problem. The problem can range from finding the shortest path as in traveling salesman problem, to finding the best transmission power to minimize the BER within the signal. Nature has provided several examples of optimization like evolution, bird flying pattern, ants finding food etc and these examples are converted into mathematical models to resolve various optimization problems by varied mathematicians. In this paper, a review of various optimization techniques employed in optimization of Multi-User Detection in CDMA system are described. The objective of optimization is to reduce the Bit Error Rate and increasing the number of users. Comparative study of various optimization techniques is summarized and discussed. Keywords—Optimization; Multi-User Detection; CDMA; Genetic Algorithm; Particle Swarm Optimization; Biogeography based Optimization algorithm.