摘要：In this paper, we consider power control for a code-division-multiple-access (CDMA)-based satellite cogni- tive radio network where the satellite acts as the common transmitter of primary users and secondary users. Specially, we assume that primary users are willing to share resource with secondary users by means of leasing spectrum, while secondary users have to pay for the shared spectrum. In addition, secondary users are allowed to transmit on any sub-channel provided that the resulting interference to any primary users is below a critical threshold. We focus on the downlink. The objective is to maximize the throughput in the licensed frequency band of the satellite network. We formulate the problem as a game theoretic problem with all users as the players. We propose a tow-phase control scheme that can be accepted willingly by both types of users and can maximize the throughput of the satellite network. In the first phase, the Nash Equilibrium point is calculated with an iterative method, the existence of the Nash Equilibrium point is also proved. In the second phase, Payoff Dominance Selection is used to choose the optimal power allocation under the constraints including quality of service protections of all users and maximum transmission power of the onboard power amplifier. Simulation is performed to study the parameters of the system and of each user. By simulation, we find that the throughput is greatly increased by the proposed scheme compared with traditional satellite networks where fixed power is allocated to only primary users. Onboard complexity is also analyzed.
