Inter-Subset Hamming Distance Maximization for Enhancing the Physical Layer Security of Antenna Subset Modulation

Omar Ansari,Abdul Rahman Muhammad Maud,Moazam Maqsood,Muddassar Farooq,Muhammad Amin

doi:10.1109/access.2020.3042969

Omar Ansari, Abdul Rahman Muhammad Maud + Show 3 more

Open Access

https://doi.org/10.1109/access.2020.3042969

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Abstract

In this article, a novel antenna subset selection technique for enhancing the Physical Layer Randomness (PLR) of Antenna Subset Modulation (ASM) has been proposed. Hamming Distance Optimized Antenna Subset Selection (HD-OASS) minimizes the correlation between the antenna subsets at transmitter by maximizing the hamming distance between the successively used antenna subsets. Unlike previously proposed Randomized Antenna Subset Selection (RASS) and Side-Lobe Level Optimized Antenna Subset Selection (SLL-OASS), in which antenna subsets are randomly selected from the codebook, HD-OASS chooses the antenna subsets having optimally maximized hamming distance. It is shown that SLL-OASS has rather unfavorable effects on encryption strength due to considerable reduction of codebook size. Furthermore, HD-OASS has been shown to outperform RASS and SLL-OASS in terms of encryption strength in the unwanted directions of eavesdropper.

Highlights

O VER the past decade, Directional Modulation (DM) has emerged as strong candidate for providing Physical Layer Security (PLS) against eavesdropping
The progressive interelement phase difference (β) is adjusted at the transmit side to point the main beam in the direction of Bob
Inter-subset hamming distance maximization has been proposed as a new antenna subset selection technique for Antenna Subset Modulation (ASM) which has been shown to significantly outperform previously proposed techniques in terms of Physical Layer Randomness (PLR)

Summary

INTRODUCTION

O VER the past decade, Directional Modulation (DM) has emerged as strong candidate for providing Physical Layer Security (PLS) against eavesdropping. Physical Layer Randomness (PLR) [22] is one of such parameters which proposes a new model for analyzing the encryption strength of DM techniques in terms of randomness introduced along the undesired directions i.e. towards eavesdropper (Eve) It maps the concepts of PLS techniques to symmetric-key block encryption ciphers, like state-of-theart Advanced Encryption Standard (AES) [23], to benchmark the encryption strength of DM techniques to strong block ciphers [24]. The inter-subset Hamming Distance Optimized Antenna Subset Selection (HD-OASS) has been proposed as a novel antenna subset selection technique for enhancing PLR (encryption strength at physical layer) of ASM. It is shown that in order to achieve PLR comparable to AES, hamming distance maximization of antenna subsets outperforms previously proposed optimization techniques. The normalized intersubset hamming distance between two vectors bi and bj is represented as dij

ANTENNA SUBSET MODULATION

SIMULATION RESULTS

INTER-SUBSET HAMMING DISTANCE OPTIMIZED CODEBOOK

DIRECTIONAL ENCRYPTION OF IMAGE USING ASM

CONCLUSION