Cognitive radio : A method to achieve spectrum sharing in LTE-R system

In order to solve the problem of spectrum waste in the LTE-Railway (LTE-R) system, the paper uses Cognitive Radio (CR) to improve the ability of spectrum sharing on Vehicle-to- Ground communication. By constructing a novel Cognitive Radio Network (CRN) in LTE-R system, the Cognitive LTE-R eNodeB (C-eNodeB) can work with Vehicle Gateway (VG) and allocate idle and wasted spectrum resources to the passengers communicating devices to improve spectrum utilization of LTE-R, without impacting train-ground communication. Aiming at the novel CRN architecture, a C-eNodeB Queue Management Strategy (QMS) based on Type of Service (ToS) value priority is proposed to reduce the Real-Time (RT) service delay of Secondary Users (SU) caused by FIFO QMS. The simulation results show that the proposed CRN effectively improves the spectrum utilization of LTE-R system and the C-eNodeB QMS based on the ToS value priority significantly reduce the delay of RT business of passengers.