Abstract:

Cooperative sensing can effectively improve the performance in cognitive systems, and the main benefit comes from some high reliable users but not all users. The performance of the optimal fusion rule is analyzed under the system model of IEEE 802.22. Based on the analysis, a new user rejection algorithm is proposed to reduce feedback resource greatly with limited performance loss. The proposed sets a threshold to reject users with low reliability. Analysis and simulation show that the user rejection can effectively control the system performance loss by setting a reasonable threshold. Moreover, it also reduces the requirements of feedback channel resources and provides a foundation for further cooperation sensing system optimization.

Key words: cognitive radio, cooperative sensing, optimal fusion rule, user reject