Ampli-Flection for 6G: Active-RIS-Aided Aerial Backhaul with Full 3D Coverage

TL;DR

This paper introduces an active aerial RIS architecture for 6G backhaul that provides full 3D coverage, enhances line-of-sight links, and improves energy efficiency through joint optimization, outperforming existing passive solutions.

Contribution

It proposes a novel active-RIS aerial platform design for 6G backhaul, enabling 3D coverage and overcoming limitations of passive RIS approaches.

Findings

Significant performance improvement over benchmarks.

Enhanced line-of-sight and coverage capabilities.

Effective joint optimization of placement and phase configuration.

Abstract

In this paper, we propose a novel aerial backhaul architecture that employs an aerial active reconfigurable intelligent surface (RIS) to achieve energy-efficient, {full 3D coverage including UAV-BSs and ground users in 6G wireless networks}. Unlike prior aerial-RIS approaches limited to {2D coverage with only servicing ground users} or passive operation, the proposed design integrates an active-RIS onto a high-altitude aerial platform, enabling reliable line-of-sight links and overcoming multiplicative fading through amplification. In a scenario with UAV-BSs deployed to handle sudden traffic surges in urban areas, the aerial-active-RIS both reflects and amplifies backhaul signals to overcome blockage. We jointly optimize the aerial platform placement, array partitioning, and RIS phase configuration to maximize UAV-BS energy-efficiency. Simulation results confirm that the proposed method significantly outperforms benchmarks, demonstrating its strong potential to deliver resilient backhaul connectivity with comprehensive 3D coverage in 6G networks.