Research On The Application Of CMA Blind Multi-user Detection In The Satellite Mobile Communication Channel

Direct Sequence-Code Division Multiple Access(DS-CDMA) communication systems are interference-limited systems. A CDMA system employing conventional detect techniques will be degraded in performance and limited in capacity because of multiple access interference(MAI) and near-far effects. Multi-user detector (MUD) is one of the key techniques for these problems in CDMA systems, which deals with multiple access interference as useful information and eliminates it by utilizing correlation characteristics between signature waves. MUD techniques can dramatically relax "near-far" effects, significantly improve the system's performance and increase the capacity of CDMA systems. Due to the self-interference, satellite mobile communication system includes MAI when using CDMA manner, which influences the capacity of the system. Multi-user detection (MUD) is an effective way to resist interferences and is very important for the limited satellite transponder's resource. Recently blind multi-user detection attracts more and more attentions. There are three blind multi-user detection Technologies: subspace-tracking algorithm, constant modulus and the method base on cyclostationarity. Therefore, this paper mainly studies the application of CMA blind multi-user detection.This paper mainly uses the method include theory analysis and computer simulation to study .The paper first studies the statistical characteristics of the satellite mobile communication channel, then gives the model of simulation. It analyses the CMA and then gives the modified linearly constrained constant modulus algorithm, and based on this , we simulate the performance.The purpose of this paper is to come up two modified linearly constrained constant modulus algorithm (FMLCCMA and VMLCCMA) based the study of CMA , analyze and simulate the performance. The paper also puts the two modified algorithm into the application of blind multi-user detection and gives the performance contact to the traditional multi-user detection, which tells us that the performance of FMLCCMA and VMLCCMA multi-user detection is better than traditional multi-user detection.