Antenna Subset Modulation With Sidelobe-Suppressed Randomness-Driven Synthesis for Secure mmW Communication

Antenna Subset Modulation (ASM) achieves directional encryption of data by leveraging time-varying antenna subsets modulated randomly at symbol rate. This paper introduces a multi-objective joint optimization approach based on Sidelobe Level (SLL) suppression and randomness-driven array synthesis for ASM, named SLL-suppressed inter-subset Hamming Distance (SLL-HD) optimization. The algorithm runs in two steps. First, the average sidelobes are reduced through Simulated Annealing (SA). Second, the codebook is redesigned by reducing the correlation between successive subsets in the codebook. Overall, the proposed scheme carries dual benefits of low SLL and high randomness-yielding codes. SLL-HD is demonstrated to outperform existing subset selection techniques of ASM in terms of Symbol Error Rate (SER), secrecy capacity, and cryptographic measures of Physical Layer Randomness (PLR) & Cumulative PLR (CPLR). The computational complexity of the proposed scheme is lower than existing algorithms. More importantly, it achieves higher Physical Layer Security (PLS) performance with least codebook space report in the literature so far.