Time-Sensitive Mobile User Association and SFC Placement in MEC-Enabled 5G Networks

The ongoing roll-out of 5G networks paves the way for many fascinating applications such as virtual reality (VR), augmented reality (AR), and autonomous driving. Moreover, 5G enables billions of devices to transfer an unprecedented amount of data at the same time. This transformation calls for novel technologies like multi-access edge computing (MEC) to satisfy the stringent latency and bitrate requirements of the mentioned applications. The main challenge pertaining to MEC is that the edge MEC nodes are usually characterized by scarce computational resources compared to the core or cloud, arising the challenge of efficiently utilizing the edge resources while ensuring that the service requirements are satisfied. When considered with the users' mobility, this poses another challenge, which lies in minimization of the service interruption for the users whose service requests are represented as service function chains (SFCs) composed of virtualized network functions (VNFs) instantiated on the MEC nodes or on the cloud. In this paper, we study the problem of joint user association, SFC placement, and resource allocation, employing mixed-integer linear programming (MILP) techniques. The objective functions of this MILP-based problem formulation are to minimize (i) the service provisioning cost, (ii) the transport network utilization, and (iii) the service interruption. Moreover, a heuristic algorithm is proposed to tackle the scalability issue of the MILP-based algorithms. Finally, comprehensive experiments are performed to draw a comparison between these approaches.

I. Introduction

The 5th generation (5G) of cellular networks promises to transform the mobile communication landscape by offering an extremely high quality of experience (QoE), sub-millisecond latency, higher connection density, multi-Gbps data rates, and so forth to the human and non-human end-users [1]. This opens the door for new revenue streams for mobile network operators (MNO) and the third-party service providers, enabling them to offer many novel applications and services, such as augmented reality, virtual reality, autonomous driving, high-definition sensor sharing, whose stringent QoS have not been able to satisfy with the previous generations of mobile networks [2]. Nonetheless, it also calls for novel technological solutions to meet the requirements of such applications. Multi-access edge computing (MEC) [3] is one of such technologies that is expected to play a pivotal role in 5G networks by shifting the applications, services, and processing capabilities closer to the end-users and, therefore, offloading the transport network and reducing the round-trip delay experienced by the end-users. For instance, owing to the network function virtualization (NFV) technology, MEC enables the 5G core network functions and applications to be deployed at the network edge as a chain of virtualized network functions (VNFs) known as service function chains (SFCs) [4].