POWER ALLOCATION FOR SENSING BASED SPECTRUM SHARING COGNITIVE RADIO NETWORK WITH MULTIPLE PRIMARY USERS
K R SHANTHY M SUGANTHI V KEJALAKSHMI
In this paper, considering multiple primary users in a cognitive radio network, the problem of optimal power allocation strategy is studied to maximize the capacity of the secondary system. The primary users are each licensed to an adjacent narrowband channel and the secondary users simultaneously sense multiple narrow band channels and aggregate them for transmission. The system model with multiple primary users is proposed and sensing based spectrum sharing scheme is considered and it is compared with opportunistic spectrum sharing scheme under average interference power constraint at each primary user and average transmit power constraint of secondary user. An algorithm is proposed to maximize the capacity of the secondary system using Lagrange dual decomposition method to find the optimal power. The optimal power allocation strategy that maximizes the outage capacity of the secondary system under average transmit and interference power constraint is also considered. Simulation results show that the proposed system maximizes the channel capacity of the cognitive users under certain interference thresholds of the authorized users, thus increasing their transmission rate.
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