An experimental study of acoustic distributed beamforming using round-trip carrier synchronization

This paper describes the development of an acoustic distributed beamforming system and presents experimental results for two-source and three-source acoustic distributed beam-forming using the time-slotted round-trip carrier synchronization protocol. Each source node in the system was built using commercial off-the-shelf parts including a Texas Instruments floating-point digital signal processor, microphone, speaker, audio amplifier, and battery. The source node functionality, including phase locked loops and the logic associated with the time-slotted round-trip carrier synchronization protocol, was realized through real-time software independently running on each source node's C6713 digital signal processor. Experimental results for two-source and three-source realizations of the acoustic distributed beamforming system in a room with multipath channels are presented. The two-source and three-source experimental results show mean power gains of approximately 97.7% and 90.7%, respectively, of an ideal beamformer.