# Spatial and Directional Modulation Systems for Near-Field Secure Transmission

## TL;DR

This paper introduces a new secure communication system for 6G networks using spatial and directional modulation with artificial noise to improve security and efficiency.

## Contribution

The novel SDMN-AN framework combines spatial and directional modulation with artificial noise to enhance near-field communication security and spectral efficiency.

## Key findings

- The SDMN-AN framework significantly improves spectral efficiency and mitigates eavesdropping threats.
- Analytical and simulation results confirm the superiority of the proposed system over existing methods.
- MRT and ZF precoding strategies offer different trade-offs between hardware complexity and detection overhead.

## Abstract

The proliferation of massive antenna arrays and the consequent intensification of near-field effects with 6G necessitate addressing critical security challenges in near-field communication environments. This paper presents a novel artificial noise-aided spatial and directional modulation (SDMN-AN) framework, specifically tailored for secure near-field communications. The proposed system integrates legitimate receiver indices, modulation symbols, and artificial noise (AN) confined to the null space of legitimate channels, thereby enhancing both spectral efficiency and communication security. Two precoding strategies—maximum-ratio transmission (MRT) and zero-forcing (ZF)—are investigated, offering trade-offs between hardware complexity and detection overhead. Analytical derivations of bit error rate (BER) bounds, corroborated by simulation results, underscore the superiority of the SDMN-AN framework in mitigating eavesdropping threats while significantly improving spectral efficiency, positioning it as a compelling solution for next-generation secure wireless networks.