A centralized inter-network resource sharing (CIRS) scheme in IEEE 802.22 cognitive networks

IEEE 802.22 is a standard for Wireless Regional Area Network (WRAN) based on cognitive radio techniques. It allows sharing of geographically unused spectrum allocated to the Television Broadcast Service, without causing harmful interference to the licensed users. An open issue in cognitive 802.22 networks is represented by the resource distribution among WRANs. The contribution of this paper is a resource sharing algorithm which assigns resources to overlapped WRANs in such a way to avoid harmful interference among them. Specifically, we propose a collision free resource sharing method which, working in a multichannel environment, aims to assign band to the coexisting WRANs, satisfying their spectrum demand and determining a fair spectrum scheduling. The novel method adapts to the continuous changes of the spectrum availability due to necessity of vacating a channel in case of the incumbent primary users or otherwise due to the addition of unused band. Moreover, the introduced allocation scheme takes into account the issue of spatial diversity, i.e. the case where some channels do not spatially cover all the WRANs. The effectiveness of the proposed multichannel resource sharing scheme is proved through simulations, and the results, compared with other methods already known in literature, show that the algorithm makes a resource assignment which satisfies the requests and improve the use of the available channels, increasing the spectral efficiency.