Blind source separation and equalization in asynchronous MIMO DS-CDMA

In an asynchronous DS-CDMA system of multiple users where the orthogonality of spreading codes is broken, both uplink and downlink receptions face inter-symbol interference (ISI) and multiple access interference (MAI). Compared to traditional receiver techniques which require channel state information (CSI) and spreading codes, detection via blind source separation (BSS) may use only oversampling of the received signals. Furthermore, when a multi-antenna structure is imposed, BSS will attempt optimization of multiple-input multiple-output (MIMO) multiplex gain. Trade-offs of different equalization and detection schemes are also discussed in this paper and simulations for various scenarios are included.