A new signaling scheme for large DS-CDMA channels without CSI

We propose a novel signaling scheme for wireless communication systems without channel state information (CSI). In that scheme, a bias of the occurrence probabilities of constellation points is utilized as pilot information known to the receiver, whereas pilot signals known to the receiver are sent in conventional pilot-based approaches. We evaluate the performance of the new scheme and conventional pilot-based schemes for a large direct-sequence code-division multiple-access (DS-CDMA) system, by using the replica method. It is shown that the new scheme outperforms the conventional pilot-based scheme when the amount of pilot information is large.