NFV and SFC: A Case Study of Optimization for Virtual Mobility Management

To support the typical application scenarios defined in the fifth generation wireless network, such as the enhanced mobile broadband, massive machine type of communication, ultra-reliable and low-latency communication, virtual Mobility Management Entity (vMME) is a promising solution, which runs on universal servers and network functions virtualization instead of conventional hardware-dedicated mobility management entity. Among different vMME mapping solutions, the decomposing of MME into multiple components is a prospective approach to implementing distributed and virtualized mobility management. In this paper, the optimization of mobility management is addressed by using NFV and service function chain. A general signaling processing flow of vMME based on service function chain is analyzed. The performance of vMME is formulated considering the total signaling communication overhead cost, the total signaling communication overhead cost on backhauls as well as the migration overhead cost of state data under different function component placement of vMME. Since this optimization problem is NP-hard and the computation complexity is O(n
^k
), a heuristic approach consisting of Min-TSCOC, MinTSCOCB, and Min-MOCSD are presented, which aims to obtain the optimal solutions to the optimization problems by using genetic algorithm. The simulation results show that it is beneficial to decompose the function of mobility management, and the performance gains from vMME for different network function composition strictly depend on four mobility events.