Determination of Sensing Time Using Average SNR and the Number of Cooperative Cognitive Nodes for Cognitive Radio Networks

Abstract

In cognitive radio networks, we propose a simple method to determine a sensing time for achieving the good throughput close to the optimal throughput in cognitive radio networks. Multiple cognitive nodes cooperate to sense the state of the primary user and the head of cognitive nodes, i.e. the secondary Tx node, finally decides the state of the primary user by majority of individual decision from each cognitive node. Using the average received SNR from the primary user and the number of cognitive nodes, each cognitive node determines the sensing time. After the sensing duration, if the secondary Tx node decides that the primary user is inactive, then the secondary Tx transmits a data to the secondary Rx during the transmission duration. With only the determined sensing time shorter than the full sensing time, we can obtain the nearly optimal throughput of secondary user while the primary user is protected sufficiently.