Blind equalization of DS-CDMA and MC-CDMA modulations in time-variant frequency selective channels

The paper addresses the blind equalization problem of spread spectrum modulations in the presence of fast time-variant frequency-selective channels. The basic assumption of the paper is that the channel response exhibits fast changes. A second goal of the paper is to force the definition of a universal CDMA blind equalization scheme that is capable of performing for DS-CDMA or multi-carrier CDMA signal modulations without any modification in the equalizer. The formulation of the equalization scheme allows the consideration of temporal and/or spatial diversity front-end receivers. The result is a high-performance system that uses a deterministic blind criterion to equalize the channel, avoiding the use of stochastic methods. The proposed technique performs direct channel equalization without previous channel estimation. Although the proposed equalizer in this work performs equalization at chip rate, this paper suggests a solution to achieve equalization at lower rates.