Auxiliary Vector Receiver Multiple Access Interference Performance

Multiple access interference (MAI) is the main reason that affects the performance of CDMA systems. Thus MAI suppression has become the focus of the CDMAtechnology. In this thesis, a new MAI suppression approach--the auxiliary-vector(AV) receivers is mainly discussed. Firstly, the basic principle of the single AV receiver is studied. The AV is selected under a maximum magnitude cross-correlation criterion and its calculation involves only the spreading sequence of the expected user and the autocorrelation matrix of the received data, no matrix inversion operation is required. Secondly, it is extended to multiple AV receiver. A sequential procedure for conditional AV optimization is put forward and the multiple auxiliary vector algorithm is simplified through an observation on the construction of the auxiliary vectors. Then the influence of AV's number on the AV receiver's performance is studied through simulations. The results indicate that better performance can be obtained using a few AVs. Finally, simulation results included in this work suggest that at only a minimal increase of the complexity, the single auxiliary vector receiver outperforms significantly the conventional correlating receiver and that the multiple auxiliary vector receiver compares favorably, both complexity-wise and performance-wise, to the decorrelating detector and the MMSE detector.