Novel region division approach for joint space-time spectrum 2-dimensions sensing in cognitive radio

Joint space-time sensing can effectively explore spectrum resources from 2-dimensions in cognitive radio networks. A novel region division approach is proposed to clarify the structure of the heterogeneous cognitive radio network. According to the application requirements of the IEEE 802.22 standard, the new approach establishes a space-time robust sensing model. Primary user (PU) distribution region, protection region and secondary user (SU) sensing region are clearly defined. By restricting the outage probability of the primary user, closed-form bounds of three regions are obtained. Based on the transmission power of the PU and the maximum transmission power of the SU, the proposed approach can flexibly determine user distribution regions and the Overlay and Underlay access modes of the SU. Numerical and simulation results verify that the proposed approach can guarantee the communication quality of the PU, and exhibit more flexibility and efficiency in spatial spectrum resources allocation and access.