Modeling and Analysis for Spectrum Handoff in Cognitive Heterogeneous Wireless Network

Abstract

In cognitive heterogeneous wireless network where the open wireless network and the cognitive radio network coexist, we use the queuing theory to model the spectrum handoff of secondary user(SU), solving the problem of large secondary user service delay. First, a cognitive heterogeneous wireless network environment is established based on the shared unlicensed spectrum as well as the opportunity utilization authorized spectrum in cognitive radio network. Then, a novel dynamic data adjustment scheme is proposed based on the channel historical state information. Combining with the user classification and the PRP/NPRP M/G/1 queue model, we analyze the secondary users’ extened data transmission delay in spectrum handoff, and propose an adaptive frequency handoff strategy to minimize the delay. Finally, the simulation results show that the proposed cognitive heterogeneous wireless network can realize the network coexistence and improve the spectrum utilization efficiency. Meanwhile, the proposed adaptive spectrum handoff strategy can effectively reduce the transmission delay of delay-sensitive secondary users, while improve the service performance of non-delay-sensitive ones.