Linear interference cancellation in CDMA based on block iterations

It has previously been shown that well-known iterations for solving a set of linear equations correspond to linear interference cancellation structures for short-code CDMA. Here, we suggest applying a block-wise iteration which consists of an outer and an inner iteration. This approach makes it possible to extend the equivalence to include long-code asynchronous CDMA. The outer iteration used is the Gauss-Seidel method while for the inner iteration, we study the Jacobi and the Gauss-Seidel iterations, their over-relaxation extensions as well as the conjugate gradient iteration. It is then possible to relate all the iterations to cancellation structures directly in the time domain and to determine relaxation factors in a timely manner. The performance of the detectors is studied via computer simulations