Prior ICA based blind multiuser detection in DS-CDMA systems

ICA based blind source separation methods suffer from inherent scaling and permutation ambiguities , which would cause problems in a DS-CDMA multiuser detection and MAI mitigation scenario. Recently ICA methods incorporating prior information about the desired user´s code were proposed as an add-on to the subspace MMSE detector. In this paper, we propose a Q-R decomposition based technique to initialize the ICA algorithm in order to remove the permutation ambiguity as well as to avoid the explicit subspace computations. It is shown via simulations that the proposed technique is more robust in the case of highly correlated unequal energy users.