Effect of sensing ability for spectrum shared cognitive radio - Power control or CSMA -

In this paper, we analyze a spectrum shared cognitive radio based on a power control and a time sharing for avoiding the inter-system interference between a primary system and a secondary system on the same frequency. In general, only the secondary system avoids giving interference toward the primary system by controlling the communication parameters like transmit power, frequency, transmit timing. However, if the primary system has a carrier sense function like wireless LAN, the time sharing based on carrier sense also can be considered for spectrum sharing method because the primary system also has some interference avoidance function. Then, we analyze a spectrum shared performance by focusing on the spectrum sensing function setting on both of the primary transmitter and the secondary transmitter. We confirm that the appropriate spectrum sharing method can be selected according to the sensing level of each system and the distance between the primary transmitter and the secondary transmitter.