The Stability of Signal to Interference and Noise Ratio with Powers and Gains Change in Cognitive Radio Network

The signal to interference and noise ratio (SINR) is a key parameter to guarantee the quality of services in cognitive radio network (CRN) and mainly influenced by transmission powers and path gains which are considered invariable in common. If powers and gains change the power control based on SINR perhaps generates the positive feedback even the system breakdown. This paper investigates the stability of SINR with powers and gains change. A differential dynamic equation is built based on CRN and the stability of SINR with powers and gains change is done theoretical analysis by center manifold theory. Some conclusions are drawn under special conditions which show that SINR will become convergence in restrictions with fixed gains and have no stability with fixed powers. The numeric simulations are provided to testify the effectiveness.