Application Of Bionic Algorithm In Multi-user Detection Of 3G Mobile Communication System

The advantages of Code Division Multiple Access(CDMA) have made it become the core technology of the third generation wireless communication system, but the system performance and capacity is limited by the Multi-Access Interference(MAI). Multi-user Detection(MUD) is the key interference cancellation technology of the wideband CDMA communication system, the optimal MUD can overcome the MAI theoretically, but it can not be carried out under the current technological condition due to its high complexity. In order to solve the contradiction, people are searching for new sub-optimum MUD methods.This paper uses two improved Bionic Algorithms to deal with the problem on CDMA multi-user detection. Firstly, put forward the Adaptive Immune Algorithm and put it in multi-user detection. This kind of algorithm can adaptively pick up the effective information from the gene of the best individual to make the immune vaccine. Meanwhile, during the process of inoculating the vaccine, lead in a parameter which is self-adapting to the changes to express the percentage of the vaccine which has been inoculated. In synchronous and non synchronous CDMA system, with less complex computation than the optimizing detection, it can get the efficiency which is approximate to the optimizing detection by using the multi-user detection which is on the basis of Adaptive Immune Algorithm. Secondly, bring up a CDMA multi-user detection which is on the basis of Adaptive Ant Colony Algorithm. This method adopts the culling strategy, which combines the definite culling with the random one and adjusts the probability of the definite culling in the searching process dynamically and increases the probability of the random culling. Thus it is useful to search the solution space thoroughly and to improve the efficiency of the solution. The simulations show that the multi-user detection on the basis of this algorithm has fine efficiency and it is suitable to deal with the CDMA multi-user detection which has larger numberof user, so it brings up a new method for CDMA multi-user detection. Lastly, conclude the whole study work in the paper and look forward to the realization of the CDMA multi-user detection and further study and application of the bionic Algorithm.