An open-loop (OL) method to enable distributed transmit beamforming is presented in this paper. The approach eliminates the need for feedback to distant receive nodes by using multiple tones to set a coherent phase across the distributed array. This arrangement is able to constantly keep the array synchronized to avoid the frequency drifting of the local oscillators (LOs) equipped by distributed communication nodes, even while transmit beamforming is taking place. This is made possible because the synchronization is achieved through radio frequency (RF) carriers at frequencies other than the beamforming frequency. This enables uninterrupted beamforming, which is not possible in previous carrier synchronization algorithms due to half-duplex limitation. The noise performance of the proposed scheme is also presented.
- Carrier synchronization
- Distributed arrays
- Distributed transmit beamforming
ASJC Scopus subject areas
- Electrical and Electronic Engineering