A Network Calculus Based Delay and Backlog Analysis for Cloud Radio Access Networks

Cloud radio access network (C-RAN) has been widely regarded as a promising techniques for 5G cellular mobile communication. By decoupling radio and baseband processing from all-in-one macro base station into remote radio head (RRH) and baseband unit (BBU) pool, C-RAN can significantly improve the flexibility and scalability of cellular mobile system with less ownership cost and operational expenditure. In 5G systems, the delay tolerance is very strict and usually limited within 5ms; while applications hold different quality-of-service (QoS) towards providing proper service. In terms of this, we classify mobile applications with different priorities, each of which holds a specified delay constraint. Based on network calculus, a theory for deterministic queuing systems, we propose an analysis method revealing delay and backlog upper-bounds for applications with different priorities, indicating the minimum required processing capacity of the C-RAN system. Numerical analysis and experiments driven by real data trace are conducted to validate the derived upper-bounds. Experiment results show that the proposed bounds for both delay and backlog in C-RAN hold great potential to guide the mobile network operator for C-RAN deployment and operation.