Energy-efficient reporting scheme for cooperative spectrum sensing

Cooperative spectrum sensing (CSS) has been proposed in order to improve the reliability of the spectrum occupancy decision in cognitive radio networks. There are two well-known schemes for cooperation among cognitive users (CUs), soft scheme (SS) and hard scheme (HS). In SS the exact local sensing result is reported to a Fusion Center (FC), usually by quantizing it with a large number of bits. In contrast, only one bit is used in HS to convey the local sensing result to the FC. The difference in the number of reported bits results in high accuracy in SS and low energy consumption in HS. In this paper, we propose a novel scheme that gets benefits from both schemes, where the proposed scheme uses only one bit, as in HS, and provides high accuracy, almost as in SS. In the proposed scheme, each CU reports only one bit on a time slot related to its actual sensing results. At the FC, the arrival time of a single bit represents the sensing result of the reporting CU. Simulation results show that our proposal outperforms both HS and SS in terms of detection accuracy and energy efficiency.