Antenna selection for NR-STAR-MQAM spatial modulation

A new multiple-ring star-M-ary quadrature amplitude modulation-aided spatial modulation (NR-STAR-MQAM-SM) scheme is proposed. The aim is to minimise the average bit error probability (ABEP) of the system. Then in the interest of further minimising the ABEP, the authors formulate a low-complexity algorithm to achieve the optimum radii of NR-STAR-MQAM-SM. This algorithm is based on a specific multiple-input multiple-output configuration and the pairwise error probability function. To validate the results of the proposed scheme, a closed-form union-bound theoretical ABEP expression is derived. Finally, to improve the error performance of NR-STAR-MQAM-SM, the authors propose a low-complexity Euclidean distance-based antenna selection (EDAS) algorithm for NR-STAR-MQAM-SM (EDAS-NR-STAR-MQAM-SM). Since all amplitude/phase modulation schemes are considered to have rotational symmetry and symmetric constellation points have the same EDAS solution, the authors achieve EDAS-NR-STAR-MQAM-SM by searching only one constellation point per symmetric constellation set. The EDAS-NR-STAR-MQAM-SM solution exhibits a significant reduction in the computational complexity compared with the conventional EDAS solution.