Multiuser beamforming in multicell downlinks for maximising worst signal-to-interference-plus-noise ratio

In a multicell scenario, two competitive beamforming design schemes are proposed to maximise the worst signal-to-interference-plus-noise ratio (SINR) in each cell for downlink transmissions. The first design adopts interference control. The authors use different interference control weighting factors to suppress the inter-cell interference effectively as each cell may experience different level of inter-cell interference. The other design is based on power control, where the authors can adjust the power of each base station to improve the system performance. Both the two improved designs keep the distributive nature of the competitive design as well as improve the worst SINR of the system. The existence of Nash equilibrium of the proposed designs is proved and the system overhead is analysed for the comparison with other distributive algorithms. Simulation results show that both the proposed competitive designs have improved performances, and the competitive design with power control outperforms that with the interference control as the transmission power increases.