Group ordered iterative soft interference cancellation for GSTBC SFH/MC DS-CDMA system

A novel group STBC SFH/MC DS-CDMA (GSTBC SFH/MC DS-CDMA) is proposed to improve the number of access users so as to fully utilize the frequency resource, especially in a bandwidth limited system. The proposed system regards the users with the same frequency-hopping (FH) pattern as the virtual group, and then assigns the users into the different sub-groups. The users in different sub-groups are assigned the different spreading codes, while the users in the same sub-group are assigned the same spreading code. When the orthogonality of the different spreading codes is destroyed, the system performance will greatly degrade. In order to suppress the multi-access interference between the sub-groups, a novel group ordered iterative soft successive interference cancellation (GOISSIC) multi-user detection is proposed. The presented receiver consists of ordering group at the receiver side in order to maximize the overall system performance, and carrying iterative soft interference cancellation (ISSIC) detection for the users in same group. Finally, we compare the performance of our presented GOISSIC with GOSIC and GSIC with "hard" decision and show that significant improvement is introduced.