Improved Extended Space Index Modulation

In this design scheme, in order to improve the transmit rate and the reliability of the wireless communication links, an improved extended space index modulation (IESIM) scheme is proposed by designing the spatial constellations. Firstly, to transmit more additional information, all of transmit antennas are partitioned into two groups, each of which is used for transmitting one modified ESIM vector. Secondly, based on the design of the ESIM, the spatial vectors with two active transmit antennas are considered for the modified ESIM vectors. Furthermore, the squared minimum Euclidean distances are provided and compared with the existing classic index modulation schemes, and the bit error probability is obtained. Finally, the comparisons of the bit error rate performances are provided by simulation results with the maximum likelihood (ML) detector using MATLAB software.