Sparse code multiple access (SCMA) is a candidate technology for further wireless communication system to enhance the multiple access capacity. The existing multi carriers technique based SCMA schemes, such as orthogonal frequency division multiplexing (OFDM), have been well studied and considered as a promising candidate for future 6G protocols. However, the high peak-to-average power ratio (PAPR) issue resulted by the multi carriers techniques limits the applications of SCMA in long distance transmission scenarios and low cost sensor networks. To address this issue, single carrier based SCMA transmission scheme (SC-SCMA) has been proposed and demonstrates low PAPR. But the multi user signal detection is still a major chal-lenge for SC-SCMA, especially for frequency selective channels (FSC). In this paper, we establish the interference model of SC-SCMA system in FSC, and construct an extended factor graph (EFG) for multi user detection. Afterward, the Gaussian approx-imate interference based belief propagation algorithm processing on EFG (E-GAIBP) is proposed, realizing efficient detection and complexity reduction. Furthermore, to earn higher performance gain, joint E-GAIBP detection and LDPC decoding scheme (E-GAIBP-JDD) is introduced. Numerical results demonstrate that compared with classical MPA using EFG, E-GAIBP shows great complexity reduction and E-GAIBP-JDD performs great performance gain.
Receiver Designs for SC-SCMA Systems Over Frequency Selective Channels
2024-06-24
1637132 byte
Conference paper
Electronic Resource
English