关键词： Internet of Things   edge servers   multiserver edge networks   energy-latency tradeoff   subtask offloading   mobile edge computing   resource-limited devices   scheduling   logical dependency   resource allocation   dependency guarantees   IoT tasks   edge computing   energy consumption   telecommunication power management   mobile devices   key promising method   Internet   IoT applications   computer network security   cloud computing   mobile computing   network   dependent graphs   offloading scheme   resource-constrained devices   dependent task offloading   task scheduling  

摘要： With the rapid development of Internet-of-Things (IoT) and mobile devices, the IoT applications become more computation-intensive and latency-sensitive, which bring severe challenges to the resource-limited devices. Mobile Edge Computing has served as a key promising method to enhance the network's computing capability by enabling resource-constrained devices to offload tasks to the edge servers. A major challenge, which has been overlooked by most existing works on task offloading, is the dependencies among tasks and subtasks. In this paper, the subtask offloading with logical dependency for IoT applications is focused on. Specifically, subtask dependent graphs are employed to explore the dependency of subtasks and consider the priority of task scheduling. Further, an offloading scheme is put forward for minimizing both task latency and energy consumption of the device with dependency guarantees for all IoT tasks in multi-server edge networks. Finaly, the simulation results demonstrate that the overall reduction rate is around 14% and relatively stable can effectively reduce task latency in multi-server edge networks.

关键词： Device-to-device communication   Transceivers   Spread spectrum communication   Servers   Wireless networks   Wireless sensor networks   Time-frequency analysis   Mobile edge computing   wireless MapReduce   multi-level over-the-air (OTA) aggregation   multihop D2D communications   transceiver optimization  

摘要： In this paper, we consider a wireless multihop device-to-device (D2D) based mobile edge computing (MEC) system, where the destination wireless device (WD) is scheduled to compute nomographic functions. Under the MapReduce framework and motivated by reducing communication resource overhead, we propose a new multi-level over-the-air (OTA) aggregation scheme for the destination WD to collect the individual partially aggregated intermediate values (IVAs) for reduction from multiple source WDs in the data shuffling phase. For OTA aggregation per level, the source WDs employ a truncated channel-inverse structure multiplied by their individual transmit coefficients in transmission over the same time-frequency resource blocks, and the destination WD finally uses a receive filtering factor to construct the aggregated IVA. Under this setup, we develop a unified transceiver design framework that minimizes the mean squared error (MSE) of the aggregated IVA at the destination WD subject to the source WDs' individual power constraints, by jointly optimizing the individual transmit coefficients of the source WDs and the receive filtering factor of the destination WD. The formulated power-constrained MSE minimization problem is non-convex. First, based on the primal decomposition method, we derive the closed-form solution under the special case of a common transmit coefficient. This shows that the common transmit coefficient of the source WDs is determined by the minimal transmit power budget among them. Next, for the general case, we transform the original problem into a quadratic fractional programming problem, and then develop a low-complexity algorithm to obtain the (near-) optimal solution by leveraging Dinkelbach's algorithm along with the Gaussian randomization method. Numerical results are provided to demonstrate the significant performance gains achieved by the proposed multi-level OTA aggregation scheme over various existing schemes.

关键词： Mobile edge computing   Computation offloading   Resource allocation   Energy consumption   Algorithm design  

摘要： With lower network latency and powerful hardware, mobile edge computing (MEC) is effective for computation-intensive and delay-sensitive tasks. The rising energy and low-latency demands of mobile applications for MEC pose challenges to task allocation. In this work, we consider computation offloading in MEC that is composed of a set of mobile devices, each with multiple tasks to offload to a nearby MEC server, with both single and multiple access points (APs). With multiple APs deployed, each mobile device can directly communicate with one or more APs, and their tasks can offload to different MEC servers that are within direct communication range. By considering binary computation offloading mode and limited subchannels, we formulate the multitask allocation problem as an integer programming problem, with the objective of minimizing the total energy consumption of all mobile devices while meeting deadline requirements. To solve this complicated problem, we propose efficient algorithms for single and multiple APs, and analyze related properties, including the approximation ratio and complexity. Experiments show that the algorithm can find high-quality solutions in a short time.

关键词： Offloading optimization   Time allocation   Task offloading   Mobile edge computing  

摘要： This paper considers a wireless energy transfer based mobile edge computing system, where wireless devices can be charged by the radio-frequency signals broadcast by hybrid access point. With Mobile Edge Computing (MEC), wireless devices can execute their computation tasks locally or offload them to the MEC server by time division multiple access protocol. Based on this system, this paper studies the problem of system energy efficiency maximization by joint optimization of computing time allocation, energy consumption, capacity of local computing and task offloading. A Tabu search based system energy efficiency maximization algorithm is proposed for solving the optimization problems. Finally, the performance of the proposed algorithm is valued by extensive simulation experiments. Simulation results verify the effectiveness of the proposed algorithm.

关键词： Mobile edge computing  

摘要： With the advances of the Internet of Things (IoT) and 5G/6G wireless communications, the paradigms of mobile computing have developed dramatically in recent years, from centralized mobile cloud computing to distributed fog computing and mobile edge computing (MEC). MEC pushes compute-intensive assignments to the edge of the network and brings resources as close to the endpoints as possible, addressing the shortcomings of mobile devices with regard to storage space, resource optimisation, computational performance and efficiency. Compared to cloud computing, as the distributed and closer infrastructure, the convergence of MEC with other emerging technologies, including the Metaverse, 6G wireless communications, artificial intelligence (AI), and blockchain, also solves the problems of network resource allocation, more network load as well as latency requirements. Accordingly, this paper investigates the computational paradigms used to meet the stringent requirements of modern applications. The application scenarios of MEC in mobile augmented reality (MAR) are provided. Furthermore, this survey presents the motivation of MEC-based Metaverse and introduces the applications of MEC to the Metaverse. Particular emphasis is given on a set of technical fusions mentioned above, e.g., 6G with MEC paradigm, MEC strengthened by blockchain, etc. © 2022, CC BY.

关键词： Mobile edge computing  

摘要： In edge computing, users’ service profiles are migrated between edge servers due to user mobility. Reinforcement learning (RL) frameworks have been proposed to do so, often trained on simulated data. However, existing RL frameworks overlook occasional server failures, which although rare, impact latency-sensitive applications like AR/VR and real- time obstacle detection. These rare failures, being not adequately represented in historical training data, pose a challenge for data-driven RL algorithms. We introduce FIRE, a framework that adapts to rare events by training a RL policy in an edge computing digital twin environment. We propose FIRE-ImRE, an importance sampling-based Q-learning algorithm, which samples rare events proportionally to their impact on the value function. FIRE considers delay, migration, failure, and backup placement costs across individual and shared service profiles. We prove FIRE-ImRE’s boundedness and convergence to optimality. Next, we introduce novel deep Q-learning (FIRE-ImDQL) and actor critic (FIRE-ImACRE) versions of our algorithm to enhance scalability. We extend our framework to accommodate users with varying risk tolerances of rare failure events. Through trace-driven experiments, we show that FIRE reduces edge computing costs compared to vanilla RL and the greedy baseline in the event of failures. © 2022, CC BY.

关键词： Mobile edge computing   Blockchain   Smart contract   Data caching   Data transaction  

摘要： The emergence of mobile edge computing can provide technical support for the development of Internet services and for coping with massive data traffic, thereby reducing network latency and ensuring efficient network operations and service delivery. However, the mobile edge computing environment is prone to data loss and privacy leakage, and data security and reliability cannot be guaranteed. The application of blockchain technology ensures the stability and dependability of data caching and transactions. In order to guarantee the security of data caching in the mobile edge computing environment and minimize the response time of caching servers, this paper proposes a decentralized data caching strategy in the mobile edge computing environment. The strategy uses a greedy algorithm to make the transmission delay of the requested content as small as possible under the multiple constraints of the storage space of each server and whether the content is cached on the server. To address the problem that data trading platforms are unable to afford the computation and storage of massive amounts of data and cannot guarantee that the data will not be leaked, this paper proposes a secure decentralized data transaction program. The scheme promotes the increase of transaction turnover rate and improves the revenue of both participating parties by establishing a buyer-seller matching algorithm. According to the experimental results, the proposed data caching strategy can improve the cache hit rate and reduce the transmission delay;the proposed data transaction solution can increase the revenue of both the data holder and the data buyer. (C) 2022 Published by Elsevier B.V.

关键词： Mobile edge computing  

摘要： In mobile edge computing (MEC) systems with energy harvesting, edge devices are powered by unstable energy harvested from the environment. To prolong the lifetime of edge devices, some computing tasks should be offloaded to MEC servers. However, computing services offered by MEC servers may be very costly. In this work, we aim to minimize total costs caused by computing services and dropping tasks while avoiding the devices running out energy. With the consideration of the unpredictability of the harvestable energy, we adopt the stochastic Lyapunov optimization framework to jointly manage energy and make task execution decisions (i.e., local executing, offloading, or dropping tasks) and develop an online algorithm which could help asymptotically obtain the optimal results for the whole system. The algorithm does not require any knowledge of the harvestable energy and the statistics of task arriving processes and can be easily implemented in a distributed manner. Numerical results corroborate that the proposed algorithm can try its best to push battery energy of edge devices to a preset parameter and effectively reduce the service costs and task drops.

关键词： Mobile edge computing  

摘要： 5G communication brings substantial improvements in the quality of service provided to various applications by achieving higher throughput and lower latency. However, interactive multimedia applications (e.g., ultra high definition video conferencing, 3D and multiview video streaming, crowd-sourced video streaming, cloud gaming, virtual and augmented reality) are becoming more ambitious with high volume and low latency video streams putting strict demands on the already congested networks. Mobile Edge Computing (MEC) is an emerging paradigm that extends cloud computing capabilities to the edge of the network i.e., at the base station level. To meet the latency requirements and avoid the end-to-end communication with remote cloud data centers, MEC allows to store and process video content (e.g., caching, transcoding, pre-processing) at the base stations. Both video on demand and live video streaming can utilize MEC to improve existing services and develop novel use cases, such as video analytics, and targeted advertisements. MEC is expected to reshape the future of video streaming by providing ultra-reliable and low latency streaming (e.g., in augmented reality, virtual reality, and autonomous vehicles), pervasive computing (e.g., in real-time video analytics), and blockchain-enabled architecture for secure live streaming. This paper presents a comprehensive survey of recent developments in MEC-enabled video streaming bringing unprecedented improvement to enable novel use cases. A detailed review of the state-of-the-art is presented covering novel caching schemes, optimal computation offloading, cooperative caching and offloading and the use of artificial intelligence (i.e., machine learning, deep learning, and reinforcement learning) in MEC-assisted video streaming services. © 2022, CC BY.

关键词： Mobile edge computing   Wireless power transfer   Deep reinforcement learning   Computation rate maximization  

摘要： Since most Internet of Things (IoT) nodes are powered by small-capacity batteries and equipped with small computing units, it is difficult for them to process computing-intensive and delay-sensitive tasks. To address these two limitations, a feasible approach is to use both wireless power transmission (WPT) and mobile edge computing (MEC) technologies. Wireless edge devices (EDs) have stable energy supply by capturing radio frequency (RF) energy transmitted by the energy source and offloading computation workload to edge computing servers (ECSs) to enhance the computation rate. In this paper, an FDMA-based wireless-powered MEC network is considered, which consists of an ECS, an RF energy source and multiple EDs. The research goal is to maximize the sum computation rate (SCR) by jointly optimizing the WPT duration, energy allocation for local computation, and computation offloading, and bandwidth allocation among EDs. We first formulate this as a non-convex optimization problem that is hard to address. Then, we decompose it into a top-problem for optimizing the WPT duration and a sub-problem for optimizing the energy allocation and bandwidth allocation under a given WPT duration. An online offloading algorithm based on deep reinforcement learning (DRL) is proposed to quickly obtain the near-optimal WPT duration. For the sub-problem, we design an efficient two-stage algorithm to obtain the optimal solution. The simulation results show that the proposed algorithm can obtain the near-optimal solutions with low computation complexity.