Generalized antenna sequence spatial modulation (GASSM): a novel framework for enhanced PHY layer security and energy efficiency

Abstract

In antenna sequence spatial modulation (ASSM), the spatial and symbol domains are both used to encode information. The sequencing of the antennas’ transmissions within given time slots and the symbol carried in those time slots represent information in the spatial and symbol domains, respectively. The receiver’s task is to decode this sequence of transmission and to detect the symbol carried in the time slots, equal to the number of antennas. For better energy efficiency and greater security, we propose a generalized ASSM, GASSM. In the GASSM, while the information is contained in both the sequence and the symbols transmitted, different symbols can be transmitted within the time slots forming the frame. This expands the code domain since the symbol and the spatial information represent a longer code in the mapper table. As a special case, we present the case of three transmit antennas, transmitting within three time slots. A combination of the antennas’ sequence and the symbol carried in the time slots is used as a code for a bit sequence. Results obtained from simulation and analysis of the bit error rate performance and secrecy capacity are contrasted and presented. Comparing the GASSM to the standard spatial modulation (SM) and the ASSM, we deduce that the GASSM has a higher secrecy capacity and higher energy efficiency per bit and unlike conventional SM allows utilization of odd number of antennas.