Partitioned one-bit feedback for cooperative beamforming

Recently, it has been shown that a cooperative beamforming scheme can achieve considerable gain using node cooperation. Due to the distributed nature of cooperating nodes, it is necessary to obtain phase synchronization such that the common message transmitted from the different cooperating nodes can be added coherently at the receiver. In this paper, we present a phase synchronization algorithm which is a modified version of a previously proposed 1-bit feedback scheme. In the proposed algorithm, the total number of nodes are partitioned into subsets and each subset performs an independent 1-bit iterative process until it reaches the desired gain. We present simulation results which compare the convergence performance with the original 1-bit feedback algorithm and show that a 30% reduction in the number of iterations can be obtained when the total number of nodes are divided into 2 subsets. We also investigate the impact of the composite phase estimation of each subset on the achievable gain.