Total transmission delay minimization based spectrum selection scheme for heterogeneous cognitive radio networks

Cognitive radio networks (CRNs) are expected to improve spectrum utilization significantly by allowing secondary users (SUs) to opportunistically access licensed spectrum without affecting the normal communications of primary users (PUs). In a CRN scenario consisting of multiple heterogeneously integrated CRNs, the SUs with multiple interfaces may have to conduct network and spectrum selection for continuous data transmission. In this paper, a spectrum selection scheme is proposed which minimizes the total transmission delay of interrupted SUs in a heterogeneous CRN under the quality of service (QoS) constraints. Applying M/G/1 queue model, the waiting delay of SUs is calculated. Jointly considering the heterogeneous characteristics of CRNs, the transmission performance of target channels and the properties of queue model, the total transmission delay of SUs is formulated, and the candidate channel with the minimum total transmission delay is selected as the target channel. Numerical results demonstrate the efficiency of the proposed scheme.