Abstract-In order to support high-user-load multipleaccess (MA), we propose a non-orthogonal MA scheme based on a beneficial amalgam of spatial modulation (SM) and sparse code-division multiple-access (SCDMA), which is termed the SM-SCDMA. Hence, SM-SCDMA inherits both the merits of SM with single radio-frequency MIMO transceiver implementation and the advantages of SCDMA relying on low-complexity signal detection. In this paper, we evaluate the potential of SM-SCDMA as well as its low-complexity near-optimum signal detection. Given these objectives, we consider both the maximum likelihood detection and the message passing algorithm aided detection (MPAD) that is derived based on the maximum a posteriori principles. In order to evaluate the performance of large SM-SCDMA without relying on time-consuming simulations, we propose new approaches for analyzing the performance of SM-SCDMA systems. A range of formulas that are valid in the signal-to-noise ratio region of practical interest are derived. Finally, the performance of SM-SCDMA systems is investigated by addressing diverse design concerns. Our studies and performance results show that SM-SCDMA constitutes a promising MA scheme for the future ultra dense systems. Assisted by the MPAD, it is capable of supporting high-user-load MA transmission associated with a normalized user-load factor of two. Index Terms-CDMA, NOMA, spatial modulation, low density signature, maximum a posteriori detection, maximum-likelihood detection, message passing algorithm, performance analysis.
Furthermore, Liu et al. REF proposed a beneficial amalgamation of the spatial modulation and the sparse code-division multipleaccess (SCDMA), which is capable of supporting a very high user-load by exploiting the multiplexing gains provided by the multiple antennas and the non-orthogonality of the SCDMA.
Spatial Modulation Aided Sparse Code-Division Multiple Access
IEEE Transactions on Wireless Communications
IEEE Transactions on Wireless Communications
Mathematics Computer Science