Adaptive SINR threshold allocation for joint power control and beamforming over wireless networks

Cochannel interference is one of the main impairments that degrade the performance of a wireless link. Power control and antenna beamforming are two approaches for improving the performance in wireless networks by appropriately controlling the cochannel interference. Joint optimal beamforming and power control scheme has been considered in previous work. It has been shown that the scheme can reduce the total transmitted power and increase the maximum number of allowable users or maximum achievable signal-to-interference-noise-ratio (SINR) in wireless networks. However the previous scheme only works well in a low SINR situation. In a higher SINR situation, the total transmitted power is much higher than necessary. When the required SINR is higher than a specific value, there are no feasible solutions for power allocation. This problem is caused by the assumption that every mobile user has a fixed and the same SINR requirement (threshold). We introduce a novel adaptive SINR threshold allocation scheme with joint power control and antenna beamforming that can overcome the problems and work in real wireless communication conditions. From simulation results, we can see that our scheme reduce 60 percent of overall transmitted power and increase working area of joint power control and beamforming by 4 dB