Blind chip- and symbol rate CDMA receivers

This paper deals with the problem of blind (and semi-blind) estimation of linear DS-CDMA receivers using multiple antennas in asynchronous intersymbol interference (ISI) channels. We introduce simple relations between receivers at the symbol rate and at the chip rate and derive deterministic constraints that can be used to determine these receivers in a blind manner, with small sample sizes. The chip rate receiver is shown to be close to the MMSE receiver. Connections with existing techniques are discussed.