Nonlinear Self-Interference Cancellation for Full-Duplex Radios: From Link- and System-Level Performance Perspectives

TL;DR

This paper investigates nonlinear self-interference cancellation techniques for full-duplex radios, proposing a low-complexity method and validating performance improvements through real-time measurements and simulations.

Contribution

It introduces a novel low-complexity pre-calibration nonlinear cancellation technique and evaluates its effectiveness at link and system levels.

Findings

Significant self-interference cancellation achieved in real-time tests.

Enhanced spectral efficiency over half-duplex systems in indoor environments.

Effective nonlinear cancellation improves full-duplex performance.

Abstract

One of the promising technologies for LTE Evolution is full-duplex radio, an innovation is expected to double the spectral efficiency. To realize full-duplex in practice, the main challenge is overcoming self-interference, and to do so, researchers have developed self-interference cancellation techniques. Since most wireless transceivers use power amplifiers, especially in cellular systems, researchers have revealed the importance of nonlinear self-interference cancellation. In this article, we first explore several nonlinear digital self-interference cancellation techniques. We then propose a low complexity pre-calibration-based nonlinear digital self-interference cancellation technique. Next we discuss issues about reference signal allocation and the overhead of each technique. For performance evaluations, we carry out extensive measurements through a real-time prototype and link-/system-level simulations. For link-level analysis, we measure the amount of cancelled self-interference for each technique. We also evaluate system-level performances through 3D ray-tracing-based simulations. Numerical results confirm the significant performance improvement over a half-duplex system even in interference-limited indoor environments.