Radio admission control scheme for high-speed railway scenario: An optimal accepted service number approach

Long term evolution for railway (LTE-R) is commonly believed to be the next generation wireless communication system for high-speed railway. However, existing radio admission control (RAC) scheme in conventional LTE system can´t be used directly. The main objective of this paper is to design a RAC scheme that suits to this special environment. Considering that RAC scheme in LTE-R system should have better ability to admit huge services, in the proposed RAC scheme a resources preemption algorithm is introduced to a complete-sharing resources allocation model to maximize the number of admitted services while guaranteeing the related quality of service requirements of each service class. Complete-sharing resources allocation model can guarantee the full use of system bandwidth resource; resources preemption algorithm can make sure that all on-going services occupy optimum system bandwidth resource with their related QoS. Furthermore, the expressions of admitted service number, service blocking probability and service blocking probability are deduced using 3-dimensional Markov model. Simulation results show that the performance of the proposed scheme outperforms that of existing scheme.