Detection of Carrier-Interferometry Code Based Overloaded Multi-carrier CDMA Signals

We consider a multi-carrier CDMA system based on carrier-interferometry (CI) sequences. The CI sequences are selected because of their outstanding cross-correlation property and are used to spread multi-stream data over transform (frequency) domain. The system is overloaded by allowing an user to transmit K data streams on N < K orthogonal subcarriers or time-frequency units. This paper investigates the problem of multi-stream detection for such an overloaded system. Several suboptimal receiver structures are studied and their performance in uncoded and coded systems is investigated. We discuss the effects and usages of the channel state information on the performance of various receivers.