C2net: A Cross-Layer Quality of Service (QoS) Architecture for Cognitive Wireless Ad Hoc Networks

Cognitive Radio (CR) improves utilization of the overall radio spectrum through dynamic adaptation to local spectrum availability. In CR networks, unlicensed or Secondary Users (SUs) may operate in underutilized spectrum owned by the licensed or Primary Users (PUs) conditional upon PU encountering acceptable interference levels. A Cognitive Wireless Ad Hoc Network (CWAN) is a multihop self-organized and dynamic network that applies CR technology. The research into Quality of Service (QoS) in CWAN is still in its infancy. To date, no attempt has been made to model a QoS architecture as a unified solution for CWAN and so this is the focus of this paper. We present a novel QoS architecture called C
²
net for CWAN based on a cross-layer approach. C
²
net provides service prioritization to different traffic types in the presence of nodal mobility and PUs. The main objective is to provide stable QoS assurance to high priority flows. This is realized by a number of distributed features of C
²
net including topology management, congestion control, scheduling, and dynamic channel selection. The purpose of this paper is twofold. Firstly, to present the architectural framework based on Next Steps in Signaling (NSIS) for C
²
net. Secondly, to discuss the challenges and open issues posed by the intrinsic complexities of CWAN to spark new research interests in this field.