The Study Of ICA-Based Blind Multiuser Detection In DS-CDMA

Multiuser Detection (MUD) is a pivotal technology of code division multiple access (CDMA) communication system to suppress the present interference. In the actual CDMA system, there is some correlatedness between the users'symbol. This is why the multiple-access interence (MAI) exists. The use of independent component analysis (ICA) in CDMA communication system's multiuser detection can make good use of the independence of the users'information and then we can suppress MAI better and alleviate the problem of near-far. In this paper ,we propose two improved schemes of multiuser detection based on a modified FastICA algorithm. The modified algorithm can work well in the presence of gaussian noise, which conquers the disadvantage of using ICA only considering noise-free condition before.CDMA is a promising technology for future mobile communication system because of its several features with which other multiple access technology can not compare: higher efficiency of frequency allocation, robust anti-multipath effect, macro diversity, mitigating interference, soft capacity, low power, soft handoff, simple frequency design, easy access and so on. In CDMA communication system, the users are identified by their different sprend spectrum codes which are unique to each user, namely they are identified by the cross correlation of spread spectrum codes. If the correlation of different spread spectrum codes is not zero, there would be multi-access interference. Additionally ,CDMA communication system is a interference-limited system, that is to say that the interference directly influences the capacity of this system and the Qos of the user in the system. In order to rid the...