With the increasing demand of applications for spread spectrum technique, especially data transmission rates and spectral efficiency, advantages traditional direct sequence (DSSS) system are limited. Therefore, multi-ary (M-ary) technology, parallel combinatory (PCSS) code index modulation (CIM) technology have been proposed. Although these three new technologies can improve rate, they all face...

Reconfigurable intelligent surface (RIS)-aided communication has been regarded as one of the promising technologies for future wireless networks with regards to controlling propagation environment and enhancing quality end-to-end links. In this study, considering importance index modulation (IM) RIS-aided schemes in 6G networks, first, an orthogonal frequency division multiplexing (OFDM)-IM sys...