Performance of group ordered successive interference cancellation for multiuser detection in GSTBC SFH/MC DS-CDMA system

摘要

In this paper, we present a novel group space-time block coding slow frequency-hopping multicarrier direct-sequence code division multiple access (GSTBC SFH/MC DS-CDMA) system over frequency selective fading channels. The proposed scheme greatly improves the bandwidth-efficient through assigning the users employing the same frequency-hopping (FH) pattern. Moreover, the users employing the same FH pattern are assigned into different virtual groups, in which the users are assigned to the different spreading codes, while the users are assigned to the same spreading code in the same virtual group. Then, a novel group detection scheme that we denote by group ordered successive interference cancellation (GOSIC) is presented to suppress the interference between the different virtual groups. Our proposed scheme consists of ordering group at the receiver side in order to maximize the overall system performance, and carrying BLAST-STBC (LSTBC) detection for the users in the same virtual group. We define and derive the optimal group order based on the post group signal to interference plus noise ratio (PGSINR). We also propose another suboptimal group order in order to overcome the complexity issues. Finally, we compare the performance of our proposed GOSIC with conventional group successive interference cancellation (GSIC), conventional STBC multiuser detection (MUD), and LSTBC-MUD, and show that significant improvement is introduced. Finally, it is shown that the proposed scheme is robust to the imperfect channel estimation.