Adaptive Sensing Threshold Control Based on Transmission Power in Cognitive Radio Systems

Spectrum sensing is a key enabling technology for cognitive radio. Since there is a tradeoff between the probability of missed detection and the probability of false alarm according to a value of sensing threshold, it is very important to determine the sensing threshold suitable for cognitive radio environments. In this paper, we propose a novel method to determine the sensing threshold in the cognitive radio system, in which the secondary user (SU) first decides its transmission power for the communication and then decides the sensing threshold for the coexistence with the primary user (PU). For the coexistence, the SU controls its sensing threshold adaptively according to its transmission power in order to guarantee the minimum decodable SINR for the primary receiver. The analysis results show that the adaptively controlled sensing threshold decreases both the missed detection and the false alarm simultaneously and so enables both SU and PU to coexist in the same channel without interfering each other.