Semi-Blind Adaptive Multiuser Detection Based on Subspace Constrained Chebyshev Approximation

In this paper, a new semi-blind adaptive multiuser detection based on a subspace constrained Chebyshev approximation (CA) is proposed for multicarrier code division multiple access (MC-CDMA) uplink system. This proposed detector fully utilizes all known information to suppress the interferers within the cell, while mitigating the inter-cell interferers based on the minimum output energy (MOE) principle. A subspace constrained CA algorithm is designed to obtain the MOE weight vector adaptively, which significantly outperforms the CA algorithm. To reduce the computational complexity, an improved projecting approximation subspace tracking with deflation (PASTd) algorithm is developed for adaptive signal subspace estimation. Computer simulations show that the performance of the proposed semi-blind multiuser detection is much better than that of the blind multiuser detection based on Chebyshev approximation