Abstract:

Distributed transmit beamforming is a effective form of cooperative communication, however, The main challenges of distributed transmit beamforming include coordinating the sources for information sharing and timing synchronization and, most crucially, the distributed carrier synchronization so that the transmissions combine constructively at the destination. In this paper, we propose a distributed transmit beamforming method without any phase feedback between nodes. The concept of our approach is using reciprocity in a time division duplexed system, so that the phase offset of the forward path compensates that of the backward path; as a result, the signals from different nodes inphase combine at the destination. We also propose a transceiver prototype which is based on the OFDM technique, beamforming can be performed separately for each subcarrier.

Key words: distributed transmit beamforming;carrier synchronization;nofeedback;OFDM