Efficient relay sharing (EReSH) between multiple operators in amplify-and-forward relaying systems

In this paper, we propose several efficient suboptimal linear beamforming algorithms for an amplify-and-forward relay sharing system between multiple operators, where multiple pairs of base stations and user terminals transmit via a shared relay equipped with multiple antennas. An efficient relay sharing power minimization (EReSh-PM) algorithm is first presented to minimize the relay transmit power while meeting the signal-to-interference-plus-noise ratio requirements at each user terminal. Then efficient relay sharing rate maximization (EReSh-RM) algorithms are designed to maximize the system sum rate under a relay transmit power constraint. In particular, we design EReSh-RM algorithms for single stream and multiple stream transmissions. All the proposed EReSh algorithms are suboptimal, but they are obtained via closed-form solutions. Simulation results demonstrate that they can achieve at least the performance of the state-of-the-art schemes while no iterative procedures are required.