Spectrum Sharing by Adaptive Transmit Power Control for Low Priority Systems and its Achievable Capacity

A spectrum sharing method is proposed for the systems which share the same frequency band or adjacent bands with different priorities. The proposed method adaptively controls transmission power according to information offered by high-priority system receivers. We give theoretical capacities achieved by low-priority systems when the proposed method and a conventional method (constant transmit power) are applied. Numerical results confirm that the proposed method attains 1.5-2 times larger capacity than the conventional method.