A dynamic power management procedure in cognitive radio

To minimize interference with primary users, one of the major concerns in cognitive radio is to determine the allowable transmission power. This paper addresses the problem of power management to insure on one hand, no interference with primary user and on the other hand, the requested QoS (Quality of Service) level to the secondary transmitter. In this paper we propose a two steps method to determine the transmission power of cognitive transmissions. In the first step “Worst cases power management : WCPM”, we show that, although it´s a very quick and preventive method, using this power management procedure leads to a limitation in the range of the cognitive radio network. For this reason, we propose to use a “High Capabilities based Power Allocation and Reallocation: HCPAR”. Which is based on three algorithms “OCAA: Optimized Channel Allocation Algorithm”, “HFPRA: Handoff Free Power Reallocation Algorithm” and “HFPSRA: Handoff Free Power Switching and Reallocation Algorithm”. The results illustrate the effect of the proposed procedure, on increasing the transmission power level of the secondary users as well as the number of served cognitive nodes and on decreasing the number of channel switching (handoffs) for the cognitive transmissions.