Distributed transmit beamforming: challenges and recent progress

TLDR

Distributed transmit beamforming is a cooperative communication technique where multiple sources transmit a common message with phase alignment to combine constructively, offering gains in range, rate, energy efficiency, security, and interference reduction, but requiring coordination, timing synchronization, and carrier synchronization. This article reviews recent architectures, algorithms, and prototypes that demonstrate the feasibility of overcoming these challenges, and outlines future research directions to bring distributed beamforming into practice. The review covers promising recent architectures, algorithms, and working prototypes that illustrate how to coordinate sources, achieve timing and carrier synchronization, and realize constructive signal combination.

Abstract

Distributed transmit beamforming is a form of cooperative communication in which two or more information sources simultaneously transmit a common message and control the phase of their transmissions so that the signals constructively combine at an intended destination. Depending on the design objectives and constraints, the power gains of distributed beamforming can be translated into dramatic increases in range, rate, or energy efficiency. Distributed beamforming may also provide benefits in terms of security and interference reduction since less transmit power is scattered in unintended directions. Key challenges in realizing these benefits, however, include coordinating the sources for information sharing and timing synchronization and, most crucially, distributed carrier synchronization so that the transmissions combine constructively at the destination. This article reviews promising recent results in architectures, algorithms, and working prototypes which indicate that these challenges can be surmounted. Directions for future research needed to translate the potential of distributed beamforming into practice are also discussed.