Latency Performance Analysis And Optimization In Fog Radio Access Networks

In recent years,latency-sensitive services have been increasing.In order to meet the performance requirements of such services,wireless access networks need to provide "no-perception" ultra-low latency.The traditional wireless access network is limited by a centralized network architecture,and the network latency is large.As a promising access network solution,Fog Radio Access Network(F-RAN)is a new type of access network solution that can significantly reduce network latency by lowering part of the capability to the edge network nodes that are closer to users.In order to effectively support latency-sensitive services in F-RAN,this paper studies the latency performance in F-RAN.The main work and contributions are summarized as follows:1.Aiming at the problem of high latency of traditional wireless access network,this paper establishes a distributed computation task processing model to reduce network latency based on F-RAN distributed network architecture.The model contains three computation modes,namely local computation mode,fog node computation mode and cloud node computation mode.Based on this model,this paper studies the theoretical latency performance analysis and the latency performance optimization in F-RAN.2.Aiming at the problem that the latency performance of different computation modes in F-RAN is different and the relationship between them is not clear,this paper derives the analytical expressions of the average latency of the three modes by traversing the computation task size and channel state.Based on the above theoretical analysis results,this paper compares the average latency performance of the three modes,and gives the boundary conditions for the performance gain of the three modes.The simulation results show that the three modes can obtain performance gain under different system states.3.Aiming at the problem that improving the latency performance will increase the energy consumption in F-RAN,this paper studies the joint optimization of latency and energy consumption.By decomposing the above optimization problem into computation resources,transmission power,transmission bandwidth and offloading decision related subproblems,this paper proposes an iterative algorithm that can approximate the global optimal solution.In order to reduce the computational complexity,this paper completely decouples the offloading decision subproblem and designs a suboptimal algorithm.The simulation results show that the performance of the iterative algorithm proposed in this paper is better than the existing algorithm,and the suboptimal algorithm proposed in this paper can achieve a compromise between performance and computational complexity.In this paper,the latency performance in F-RAN is studied.The research results not only lay a theoretical foundation for F-RAN to effectively support latency-sensitive services,but also provide guarantee for the deployment of F-RAN.