Code Division Multiple Access is a widely used multiple access method in a lot of nowadays vital applications. The systems that are designed based on CDMA
are suffering from a multiple access interference problem [1]. The decorrelator
CDMA detector is a linear detector that can cancel the MAI but with some channel noise enhancement. The complexity of the decorrelator is a linear function in the number of system’s users [2]. In this research, a new detector is proposed that can
cancel the MAI in the received CDMA signal with a complexity that is independent
on the number of system’s users. The new detector does not need to know the users’ signature codes. Also it consists of two matched filter only. No correlation matrix is required. This simple structure reduces the complexity of the proposed CDMA
detector if it is compared with the conventional decorrelator detector. So, the system
capacity can be increased where from the system implementation point of view, the detector structure is simple and it does not limit the number of users in the system.
The new detector is based on some mathematical operations on the output signals
from two different matched filters. The detector idea is based on the symmetry
property of the signatures’ codes correlation matrix however it does not need to know this matrix. The algorithm is valid as long as the correlation matrix is symmetry. So it can work with synchronous and asynchronous system models. |
