Enhanced detection through signal space diversity for a coded MC-CDMA system (Best Paper Award)

Abstract

Signal space diversity defines a multidimensional signal constellation. The spread data symbols in a CDMA based transmission system, also called data chips, define a multidimensional signal constellation. However, this multidimensional signal constellation is ambiguous. The ambiguity is avoided by applying rotated spreading. In this paper we investigate an MC-CDMA system with rotated spreading. The higher signal space diversity is exploited at the receiver by a multiuser detector. The possible gains at desired bit error rates depend on the minimum Hamming distance of the used channel code. The minimum Hamming distance of the chips rises by increasing the length of the spreading sequence. Furthermore, it is shown that the enhanced signal space diversity scheme does not increase the requirements on the analog-digital converter at the receiver.