关键词： Computation offloading   Deep reinforcement learning   Mobile edge computing   Resource allocation  

摘要： Mobile edge computing (MEC) can enhance the computation capabilities of smart mobile devices for computation-intensive mobile applications via supporting computation offloading efficiently. However, the limitation of wireless resources and computational resources of edge servers often becomes the bottlenecks to realizing the developments of MEC. In order to address the computation offloading problem in the time-varying wireless networks, the offloading decisions and the allocation of radio and computation resources need to be jointly managed. Traditional optimization methods are challenging to deal with the combinatorial optimization problem in complex real-time dynamic network environments. Therefore, we propose a deep reinforcement learning (DRL)-based optimization approach, named DRJOA, which jointly optimizes offloading decisions, computation, and wireless resources allocation. The optimization algorithm based on DRL has the advantages of fast solving speed and strong generalization ability, which makes it possible to solve combinatorial optimization problems online. Simulation results show that our proposed DRJOA in this study dramatically outperforms the benchmark methods for offloading decisions and system utility.

关键词： Mobile edge computing   computing offloading   deep reinforcement learning   fairness guarantee  

摘要： Edge computing can reduce service latency and save backhaul bandwidth by completing services at network edges, providing support for diverse computation-intensive and delay-sensitive services. However, it is not practical to support all services at edge nodes due to the limited network resources. The decision that which services can be provided locally and which services should been offloaded to cloud significantly impacts the user experience. Cloud-edge computing offloading becomes an important issue in edge computing. In this paper, we take the fairness into the optimization objective of computing offloading problem, and consider both computing capacity and storage space as problem constraints. The problem is formulated as a long-term average optimization problem to maximize the alpha-fair utility function of saved time, and further translated as a Markov decision process. As the optimization problem with fairness guarantee and huge action space, we cannot solve it with traditional methods. Therefore, an innovative multi-update deep reinforcement learning algorithm is proposed which can optimize the objective with alpha -fair utility function and reduce dramatically the size of action space. We also prove the convergence of our algorithm theoretically. To our best knowledge, the long-term average optimization of computing offloading with fairness guarantee is rarely seen in literature. Extensive simulation experiments show that our algorithm can converge quickly and has better performance in terms of service delay and fairness.

关键词： Quantum approximate optimization algorithm   Generative adversarial network   Mobile edge computing   Dynamic resource allocation  

摘要： Mobile edge computing is a promising paradigm that provides edge users with dependable computing services. However, due to the dynamic nature of mobile users and the limited resources of edge servers, it is essential to emphasize the load balancing of edge servers and the cooperation of heterogeneous computing resources. This paper proposes a Dynamic Resource Allocation (DRA) scheme based on a Quantum Approximate Optimization Algorithm (QAOA). The DRA is composed of the two components listed below. Firstly, we apply generative adversarial network to predict the future user density in various regions, which is an effective resource allocation aid. Secondly, QAOA is utilized to pre-allocate edge servers resources based on an advanced model of user density. The simulation results demonstrate that the efficient application of DRA ensures the load balancing of edge servers and simultaneously alleviates communication latency.

关键词： Delay   Energy   Mobile edge computing   Task offloading  

摘要： Many tasks generated by mobile user devices are computation-intensive and latency-sensitive, such as autonomous driving and video analysis. However, due to limited energy and computing capacity, a user device may not be able to complete its task within a given time, leading to a poor user experience. Mobile edge computing (MEC) can address this challenge by offloading tasks to edge servers with stronger computing capacity and more resources for execution, which can save energy of user devices and reduce the task computation time. Different offloading strategies will impact the number of tasks completed, latency, energy overhead and so on. This paper investigates the problem of maximizing the number of completed tasks while minimizing the average completion time, energy overhead and cost in MEC under both time and energy constraints. To solve the problem, we develop the mayfly genetic algorithm (MGA), which jointly optimizes task offloading locations and ratios, central processor unit (CPU) frequencies of user devices and computing capacities allocated to user devices by edge servers. Simulation experiments indicate that MGA outperforms state-of-the-art algorithms in terms of the number of completed tasks.

关键词： Costs   Predictive models   Data models   Quality of service   Optimization   Servers   Digital twins   Mobile edge computing   digital twins   service migration   mobile traffic prediction   deep reinforcement learning  

摘要： In Mobile Edge Computing (MEC) networks, dynamic service migration can support service continuity and reduce user-perceived delay. However, service migration in MEC networks faces significant challenges due to the uncertainty in future traffic demands, the distributed architecture of MEC networks, high operating costs and the dynamism of network resources. Digital Twins (DT), which achieve the mapping of physical entities to virtual digital models in cyberspace, provide new perspectives for intelligent and efficient service provisioning in MEC networks. In this paper, we propose a traffic prediction-assisted federated deep reinforcement learning scheme to efficiently migrate services and improve the cost efficiency of DT-enabled MEC networks. Specifically, to address the coupled spatio-temporal dependencies of mobile traffic and the imbalance in traffic data, a Multi-order Spatio-temporal information integration-based distributed Traffic Prediction (MSTP) scheme is proposed, which achieves high-accuracy mobile traffic prediction at a low cost. Then, we propose a Federated Cooperative cost-efficient Service Migration (FCSM) algorithm that adaptively adjusts service migration strategies in a distributed manner to respond to future traffic demands. Moreover, a theoretical model is developed to analyze the convergence of FCSM and derive the upper bound of the time-average squared gradient norm. Finally, extensive simulations demonstrate that the proposed schemes achieve excellent traffic prediction performance, enhance users' Quality of Service (QoS), and significantly reduce the system cost of MEC networks.

关键词： Computation offloading   Machine learning   Fog computing   Mobile cloud computing   Mobile edge computing  

摘要： Today, Mobile Cloud Computing (MCC) alone can no longer respond to the increasing volume of data and satisfy the necessary delays in real-time applications. In addition, challenges such as security, energy consumption, storage space, bandwidth, lack of mobility support, and lack of location awareness have made this problem more challenging. Expanding applications such as online gaming, Augmented Reality (AR), Virtual Reality (VR), metaverse, e-health, and the Internet of Things (IoT) have brought up new paradigms for processing big data. Some of the paradigms that have emerged in the last decade are trying to alleviate cloud computing problems jointly. Mobile Edge Computing (MEC) and Fog Computing (FC) are the most critical techniques that serve the IoT. One of the common points of the above paradigms is the offloading of IoT tasks. This paper reviews machine learning-based computation offloading mechanisms in the edge and fog environment. This review covers three significant areas of machine learning: supervised learning, unsupervised learning, and reinforcement learning. We discuss various performance metrics, tools, and case studies and analyze their advantages and disadvantages. We systematically elaborate on open issues and research challenges that are crucial for the next decade.

关键词： Mobile edge computing   vehicle edge computing   digital twin network   deep reinforcement learning   task offloading  

摘要： Vehicle Edge Computing (VEC) is a promising paradigm that exposes Mobile Edge Computing (MEC) to road scenarios. In VEC, task offloading can enable vehicles to offload the computing tasks to nearby Roadside Units (RSUs) that deploy computing capabilities. However, the highly dynamic network topology, strict low-delay constraints, and massive data of tasks of VEC pose significant challenges for implementing efficient offloading. Digital Twin-based VEC is emerging as a promising solution that enables real-time monitoring of the state of the VEC network through mapping and interaction between the physical and virtual worlds, thus assisting in making sound offload decisions in the physical world. Thus, this paper proposes an intelligent partial offloading scheme, namely, Digital Twin-Assisted Intelligent Partial Offloading (IGNITE). First, to find the optimal offloading space in advance, we combine the improved clustering algorithm with the Digital Twin (DT) technique, in which unreasonable decisions can be avoided by reducing the size of the decision space. Second, to reduce the overall cost of the system, Deep Reinforcement Learning (DRL) algorithm is employed to train the offloading strategy, allowing for automatic optimization of computational delay and vehicle service price. To improve the efficiency of cooperation between digital and physical spaces, a feedback mechanism is established. It can adjust the parameters of the clustering algorithm based on the final offloading results in this clustering. To the best of our knowledge, this is the first study on DT-assisted vehicle offloading that proposes a feedback mechanism, forming a complete closed loop as prediction-offloading-feedback. Extensive experiments demonstrate that IGNITE has significant advantages in terms of total system computational cost, total computational delay, and offloading success rate compared with its counterparts.

关键词： Cross entropy   computation offloading   edge caching   mobile edge computing   profit maximization  

摘要： In this paper, we investigate a multiuser cache-enabled vehicular mobile edge computing (MEC) network, where one edge server (ES) has some caching and computing capabilities to assist the task computing from the vehicular users. The introduce of caching into the MEC network significantly affects the system performance such as the latency, energy consumption and profit at the ES, which imposes a critical challenge on the system design and optimization. To solve this challenge, we firstly design the vehicular MEC network in a non-competitive environment by maximizing the profit of the ES with a predetermined threshold of user QoE, and jointly exploit the caching and computing resources in the network. We then model the optimization problem into a binary integer programming problem, and adopt the cross entropy (CE) method to obtain the effective offloading and caching decision with a low complexity. Simulation results are finally presented to verify that the proposed scheme can achieve the near optimal performance of the conventional branch and bound (BnB) scheme, while sharply reduce the computational complexity compared to the BnB.

关键词： Mobile edge computing   C-V2X   Internet of vehicles   Deep reinforcement learning   Edge intelligence  

摘要： The integration of Cellular Vehicle-to-Everything (C-V2X) and Mobile Edge Computing (MEC) is critical for satisfying the demanding requirements of vehicular applications, which are characterized by ultra-low latency and ultra-high reliability. In this paper, we address the challenge of jointly optimizing computation offloading and resource allocation in C-V2X network. To achieve this, we propose a hierarchical MEC/C-V2X network that accounts for the dynamic changes of the vehicular network and the diversity of computation offloading patterns. Additionally, we establish a collaborative computation offloading model that supports multiple offloading patterns. We formulate the dynamic computation offloading and resource allocation problem as a sequential decision problem based on the Markovian decision process. To enable automated and intelligent decision-making, we propose a deep reinforcement learning algorithm called ORAD, based on the deep deterministic policy gradient algorithm, to maximize offloading success rate in real-time. The numerical results demonstrate that the proposed algorithm effectively provides the optimal policy, resulting in the offloading success rate of vehicular tasks being improved by 2.73% to 95.51%.

关键词： Edge server placement   Multi-access edge computing   Mobile edge computing   Optimization  

摘要： Multi-Access Edge Computing (MEC) is known as a promising communication paradigm that enables IoT and 5G scenarios by using edge servers located in the proximity of end users. As an integral part of MEC, edge servers provide virtualized resources and host different MEC applications. Therefore, user equipment and IoT devices can offload tasks to edge servers instead of remote cloud data centers. A proper edge server placement strategy can significantly improve the performance of mobile applications. The optimum number of edge servers and their placement is a problem called edge server placement. This optimization problem is NP-hard. In recent years, the research community has made great efforts to solve this problem. To achieve Quality of Service (QoS), various metrics are considered in different research papers. However, a comprehensive overview of the different aspects of the Edge Server Placement Problem (ESPP) is still missing. This paper first highlights the edge server's importance and gives its applications. Then, it provides a comprehensive summary and taxonomies based on the objectives, applications, datasets, frameworks, and strategies of the different research on the placement of edge servers. Also, this paper summarizes the ESPP and other optimization problems raised as joint optimization problems. Finally, considering the capabilities and features of the MEC environment, some open issues are presented.