关键词： Mobile edge computing   Bayesian optimization   online learning   task offloading   resource allocation  

摘要： Recent years have witnessed the emergence of mobile edge computing (MEC), on the premise of a cost-effective enhancement in the computational ability of hardware-constrained wireless devices (WDs) comprising the Internet of Things (IoT). In a general multi-server multi-user MEC system, each WD has a computational task to execute and has to select binary (off)loading decisions, along with the analog-amplitude resource allocation variables in an online manner, with the goal of minimizing the overall energy-delay cost (EDC) with dynamic system states. While past works typically rely on the explicit expression of the EDC function, the present contribution considers a practical setting, where in lieu of system state information, the EDC function is not available in analytical form, and instead only the function values at queried points are revealed. Towards tackling such a challenging online combinatorial problem with only bandit information, novel Bayesian optimization (BO) based approaches are put forth by leveraging the multi-armed bandit (MAB) framework. Per time slot, the discrete offloading decisions are first obtained via the MAB method, and the analog resource allocation variables are subsequently optimized using the BO selection rule. By exploiting both temporal and contextual information, two novel BO approaches, termed time-varying BO and contextual time-varying BO, are developed. Numerical tests validate the merits of the proposed BO approaches compared with contemporary benchmarks under different MEC network sizes.

关键词： Mobile edge computing   Trust management   Edge caching   Blockchain   Deep reinforcement learning  

摘要： Mobile edge computing (MEC) has introduced content edge caching to offload network backhaul and improve user quality of experience by transferring frequently requested content to edge nodes near end-users. However, the implementation of edge caching is fraught with significant security and confidentiality issues due to the lack of trust between the different entities involved in the caching process. Most existing solutions for managing trust in edge caching only consider the trust between caching edge servers and ignore the trust between edge servers and content providers. This paper aims to fill this gap by proposing a trust management-based edge caching system that exploits the potential of blockchain technology to secure the caching process by enabling trust between content providers and edge servers. The proposed trust management system establishes trust in both directions of the interaction, providing higher confidence between the caching actors. Our trust system is based on a direct trust score calculated using the subjective three value logic scheme (3VSL). This is complemented by a reputation-based indirect trust score managed by the blockchain. A deep reinforcement learning (DRL) algorithm is proposed to efficiently make secure and intelligent caching decisions. The simulation results show that the proposed blockchain-based trust management system is effective and guarantees a good level of security and confidentiality for edge caching. They also demonstrate that our DRL caching algorithm provides secure and intelligent caching decisions in MEC, outperforming the baseline edge caching schemes.

关键词： Digital twins   Heuristic algorithms   Approximation algorithms   Delays   Prediction algorithms   Cloud computing   Real-time systems   Digital twin   mobile edge computing   age of information   approximation and online algorithms   digital twin placement  

摘要： The emerging digital twin technique enhances the network management efficiency and provides comprehensive insights on network performance, through mapping physical objects to their digital twins. The user satisfaction on digital twin-enabled service relies on the freshness of digital twin data, which is measured by the Age of Information (AoI). Due to long service delays, the use of the remote cloud for delay-sensitive service provisioning faces serious challenges. Mobile Edge Computing (MEC), as an ideal paradigm for delay-sensitive services, is able to realize real-time data communication between physical objects and their digital twins at the network edge. However, the mobility of physical objects and dynamics of user query arrivals make seamless service provisioning in MEC become challenging. In this paper, we investigate dynamic digital twin placements for improving user service satisfaction in MEC environments, by introducing a novel metric to measure user service satisfaction based on the AoI concept and formulating two user service satisfaction enhancement problems: the static and dynamic utility maximization problems under static and dynamic digital twin placement schemes. To this end, we first formulate an Integer Linear Programming (ILP) solution to the static utility maximization problem when the problem size is small;otherwise, we propose a performance-guaranteed approximation algorithm. We then propose an online algorithm with a provable competitive ratio for the dynamic utility maximization problem, by considering dynamic user query services. Finally, we evaluate the performance of the proposed algorithms via simulations. Simulation results demonstrate that the proposed algorithms outperform the comparison baseline algorithms, improving the algorithm performance by at least 10.7\%, compared to the baseline algorithms.

关键词： mobile edge computing   wireless body area network   task offloading   reinforcement learning   D3QN   blockchain   quality of experience  

摘要： In recent years, mobile edge computing has become one of the popular methods to provide computing resources for the body area network, but existing research only considers the problem of minimizing the cost of offloading when solving the optimization problem of task-offloading, ignoring the trust problem of edge computing nodes, and offloading tasks on edge nodes may cause user information disclosure and reduce the quality of user experience. In response to this situation, this study aims to minimize the average user cost and designs a task-offloading strategy based on the D3QN (dueling double deep Q-network) algorithm in conjunction with the blockchain information security storage model. This strategy uses deep reinforcement learning algorithms to obtain the minimum average offloading cost of the system while considering user latency, energy consumption, and data protection conditions. The experimental simulation results show that compared to traditional schemes and other reinforcement learning-based schemes, this scheme can more effectively reduce the average cost of the system, and the average cost is reduced by 31.25% when reaching convergence. In addition, as the complexity of the model increases, this scheme can provide users with better experience quality, with 53.7% of the 1000 users having a very good experience quality.

关键词： Task analysis   Servers   Costs   Heuristic algorithms   Training   Scheduling algorithms   Deep learning   Deep reinforcement learning   deep q-learning   mobile edge computing   resource allocation   task offloading  

摘要： Mobile Edge Computing (MEC) is a promising solution to enhance the computing capability of resource-limited networks. A fundamental problem in MEC is efficiently offloading tasks from user devices to edge servers. However, there still exists a gap to deploy in real-world environments: 1) traditional centralized approaches needs complete information of edge network, ignoring the communication costs generated by synchronization, 2) previous works do not consider concurrent computation on edge servers, which may cause dynamic changes in the environment, and 3) the scheduling algorithm should deliver individualized decisions for different users independently and with high efficiency To solve this mismatch, we studied a multi-user task offloading problem where user devices make offloading decisions independently. We consider the concurrent execution of tasks and formulate a non-divisible and delay-aware task offloading problem to jointly minimize the dropped task ratio and long-term latency. We propose a decentralized task scheduling algorithm based on DRL that makes offloading decisions without knowing the information of other user devices. We employ Double-DQN, Dueling-DQN, Prioritized Replay Memory, and Recurrent Neural Network (RNN) techniques to improve the algorithm's performance. The results of simulation experiments show that our method can significantly reduce the long-term latency and dropped task ratio compared to the baseline algorithms.

关键词： offloading decision   Lagrange duality optimization   mobile edge computing   real-time IoT   resource allocation  

摘要： Internet of Things (IoT) devices can integrate with applications requiring intensive contextual data processing, intelligent vehicle control, healthcare remote sensing, VR, data mining, traffic management, and interactive applications. However, there are computationally intensive tasks that need to be completed quickly within the time constraints of IoT devices. To address this challenge, researchers have proposed computation offloading, where computing tasks are sent to edge servers instead of being executed locally on user devices. This approach involves using edge servers located near users in cellular network base stations, and also known as Mobile Edge Computing (MEC). The goal is to offload tasks to edge servers, optimizing both latency and energy consumption. The main objective of this paper mentioned in the summary is to design an algorithm for time- and energy-optimized task offloading decision-making in MEC environments. Therefore, we developed a Lagrange Duality Resource Optimization Algorithm (LDROA) to optimize for both decision offloading and resource allocation for tasks, whether to locally execute or offload to an edge server. The LDROA technique produces superior simulation outcomes in terms of task offloading, with improved performance in computation latency and cost usage compared to conventional methods like Random Offloading, Load Balancing, and the Greedy Latency Offloading scheme.

关键词： Task offloading   Space-air-ground integrated network   Mobile edge computing   Game theory   Nash equilibrium  

摘要： The limited coverage of terrestrial networks makes it difficult to provide low -latency and high -reliable computing services for users and Internet of Thing (IoT) devices in remote areas such as mountainous regions and oceans. Space -Air -Ground Integrated Network (SAGIN) combined with Mobile Edge Computing (MEC) can provide seamless three-dimensional services for users by deploying edge servers on satellites, Unmanned Aerial Vehicles (UAVs) and ground infrastructures. However, due to the limited heterogeneous computing resources in satellites-UAV clusters network and the energy resources of IoT devices, it brings a significant challenge in determining how to offload the computing tasks generated by ground user devices to satellite edge nodes, UAV edge nodes or locally for processing. In this paper, we first propose a satellites-UAV clusters -ground three -layer edge computing network architecture consisting of a global controller, inter -domain controllers and MEC servers. We then model the task offloading problem as a Binary Integer Linear Programming (BILP) aiming at minimizing the offloading cost composed of delay and energy consumption and prove it is NP -hard. Next, the original offloading problem is transformed to a noncooperative strategic game and the existence of Nash equilibrium is proven using potential games. Finally, we propose a Nash Equilibrium Iteration Offloading algorithm based on Game theory (NEIO-G) to find the optimal offloading strategy. Compared with other baseline algorithms, simulation results demonstrate that the NEIO-G can significantly reduce the system offloading overhead in terms of delay and energy consumption.

关键词： Mobile edge computing   Task offloading   Limited computational resources   Energy   Arithmetic optimization algorithm  

摘要： The emergence of Mobile Edge Computing (MEC) not only provides low-latency computing services for the User Equipment (UE), but also extends the battery life of the UE. However, the computational resources of MEC servers are usually limited, and how to efficiently offload UE's task and allocate the resources of MEC servers has become a research hotspot in MEC. In this paper, we develop an improved arithmetic optimization algorithm (IAOA) to optimize the convergence speed and convergence accuracy of the arithmetic optimization algorithm. Then a task offloading algorithm based on IAOA is designed to reduce the cost of offloading tasks in the framework including a single MEC server and multi-UE. The proposed algorithm jointly optimizes the task offloading strategy of the UEs and the resource allocation of the MEC server, meanwhile, models the weighted sum of delay and energy consumption as the system cost, with the goal of minimizing the system cost while satisfying the delay and energy consumption constraints of the tasks. Simulation results show that the proposed algorithm can effectively reduce the system cost and achieve a performance improvement of up to 20% compared with the benchmark algorithm.

关键词： Task analysis   Servers   Mobile handsets   Heuristic algorithms   Reinforcement learning   Costs   Deep learning   Mobile edge computing   task offloading   optimization algorithm   deep reinforcement learning  

摘要： The rapid advancement of mobile edge computing (MEC) networks has enabled the augmentation of the computational power of mobile devices (MDs) by offloading computationally intensive tasks to resource-rich edge nodes. This paper discusses the decision-making process for task offloading and resource allocation among multiple mobile devices connected to a base station. The primary objective is to minimize the time taken to complete tasks while simultaneously reducing energy consumption on the device under a time-varying wireless fading channel. This objective is formulated as an energy-efficiency cost (EEC) minimization problem, which cannot be solved by conventional methods. To address this challenge, we propose a dynamic offloading decision algorithm of dependent tasks (DODA-DT) that adjusts local task execution based on edge node status. The proposed algorithm facilitates fair competition among all devices for edge resources. Additionally, we use a deep reinforcement learning (DRL) algorithm based on an actor-critic learning structure to train the system to quickly identify near-optimal solutions. Numerical simulations demonstrate that the proposed algorithm effectively reduces the total cost of the task in comparison to previous algorithms.

关键词： Mobile edge computing   Unmanned aerial vehicle   Service caching   Workload offloading   Deep reinforcement learning  

摘要： Internet of Things devices generate a large number of heterogeneous workloads in real-time that require specific application to tackle, and the inability to communicate between devices and communication base stations due to complex scenarios is a thorny issue. Service caching play a key role in managing specific-request workload from devices, and unmanned aerial vehicles with computation and communication functions can effectively solve communication barrier between devices and ground base stations. In addition, the joint optimization of workload offloading and service cache placement is a key issue. Accordingly, we design an unmanned aerial vehicle-enabled mobile edge computing system with multiple devices, unmanned aerial vehicles and edge servers. The proposed framework takes into account the randomness of workload arrival, the time-varying nature of channel states, the limitations of the hosting service caching, and wireless communication blocking. Furthermore, we designed workload offloading and service caching hosting decision-making optimization problems to minimize the long-term weighted average latency and energy consumption costs. To tackle this joint optimization problem, we propose a request-specific workload offloading and service caching decision-making scheme based on the medley deep reinforcement learning scheme. To this end, the proposed scheme is decomposed into two-stage optimization subproblems: the workload offloading decision-making problem and the service caching hosting selection problem. In terms of the first subproblem, we model each device as a learning agent and propose the workloads offloading decision-making scheme based on multi-agent deep deterministic policy gradient. For the second subproblem, we present the decentralized double deep Q-learning scheme to tackle the service caching hosting policy. According to the comprehensive experimental results, the proposed scheme is able to converge rapidly on various parameter configurations a