Services Ranking Based Random Access Scheme for Machine-Type Communication

There is a considerable pressure for random access networks to access numerous devices with limited preambles, while the different delay requirements of diverse applications exacerbate this situation. In this paper, we propose a service ranking scheme to ensure that delays of different applications are within a reasonable range. We classify applications by latency requirements and dynamically partition preambles for serving these applications. In particular, distribute queue is used to coordinate delay-critical applications. Delay-tolerant applications are partially prohibited when congestion occurs. The average success delay is minimized under the preambles constraint. Simulation and numerical results show that the proposed scheme can effectively reduce the average success delay by 30% while guaranteeing the success ratio of delay-critical applications.