Power control for time-varying cognitive radio networks

In this paper we propose a new power control scheme for cognitive radios, Distributed Power Control Algorithm for Cognitive Radios (DPCACR). As we know that in a cognitive system, the secondary users (SU) either transmit in an opportunistic way or coexist with the primary users to transmit simultaneously under the constraints that will not harm to the primary users. Previously, the interference temperature was announced to limit the transmit power of SUs. However, in 2007 the FCC has abandoned the concept which is not workable. In this paper, we consider the elastic transmission scenario for secondary system. The cognitive networks using code-division multiple access (CDMA) technology to transmit simultaneously with primary users in the same spectral band.