Distributed channel selection for hierarchical cognitive radio networks

The most common way to ensure reliable wireless communications is an efficient frequency allocation plan. However, during rapid deployment missions or rescue operations, one can observe all limitations of traditional approach to spectrum planning. In such scenarios the solution is to use dynamic spectrum access (DSA) technology, which requires operational spectrum environment information and spectrum awareness. In practice, such information can be obtained through the use of cognitive radio (CR) nodes. Assuming that the Mobile Ad hoc Networking (MANET) network is hierarchical and contains a number of cluster heads (CH), the CHs can be used to prepare a Channel Ranking List (CRL) based on spectrum sensing information. CRL is a set of frequencies arranged by CH in a specific order, indicating their usefulness as an alternative channels in case of interference. Unfortunately, the downside of this opportunistic approach is that each CH handles only of its own regular nodes (RN) and itself. It means that any CRL in specific cluster is prepared regardless to the environments of neighboring CHs. To avoid interferences between clusters, CHs should send their CRLs to a network management point, which would enable CRL analysis and coordination. In this paper we focused on the assessment of whether the lack of such coordination has a significant influence on operational capabilities of the CR network and its ability to meet the information exchange requirement, as it is a part of military radio system, and therefore must ensure command services with required quality. To evaluate operational performance of the radio network, we propose to use a command capability factor (C2F).