Multi-stage cancellation schemes, like most of the other detection algorithms, need the knowledge of amplitude and phase of each user. In this paper, a new implementation of the cancellation scheme and an estimation method based on the Gauss-Seidel iteration are proposed, which do not need a priori knowledge of the amplitude and phase of each user. The estimation method uses averaging, and is thus only suitable for constant or slowly varying phase deviations. For constant phase offset, a block of signals as short as 50 symbols yields good results. The proposed cancellation scheme and estimation method are near-far resistant.
Simulations show that the proposed algorithm has better performance than the decorrelator.
The public is invited.