Chao Fang

Prof. Dr. Chao Fang

Beijing University of Technology
orcid

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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27 February 2018 in IEEE Communications Surveys & Tutorials
Verified
Journal Article
Closed access
Chao FangChao Fang
Chao Fang
Haipeng YaoHaipeng Yao
Haipeng Yao
ZWZhuwei Wang
Zhuwei Wang
WWWenjun Wu
Wenjun Wu
XJXiaoning Jin
Xiaoning Jin
FYF. Richard Yu
F. Richard Yu
Recently, a series of innovative information-centric networking (ICN) architectures have been designed to better address the shift from host-centric end-to-end communication to requester-driven content retrieval. With the explosive increase of mobile data traffic, the mobility issue in ICN is a growing concern and a number of approaches have been proposed to deal with the mobility problem in ICN. Despite the potential advantages of ICN in mobile wireless environments, several significant research challenges remain to be addressed before its widespread deployment, including consistent routing, local cached content discovery, energy efficiency, privacy, security and trust, and practical deployment. In this paper, we present a brief survey on some of the works that have already been done to achieve mobile ICN, and discuss some research issues and challenges. We identify several important aspects of mobile ICN: overview, mobility enabling technologies, information-centric wireless mobile networks, and research challenges.

12 December 2022 in IEEE Journal on Selected Areas in Communications
Verified
Journal Article
Closed access
GCGuangji Chen
Guangji Chen
QWQingqing Wu
Qingqing Wu
RLRuiqi Liu
Ruiqi Liu
JWJingxian Wu
Jingxian Wu
Chao FangChao Fang
Chao Fang
In this paper, we develop a unified dynamic intelligent reflecting surface (IRS) beamforming framework to boost the sum computation rate of an IRS-aided mobile edge computing (MEC) system, where each device follows a binary offloading policy. Specifically, the task of each device has to be either executed locally or offloaded to MEC servers as a whole with the aid of given number of IRS beamforming vectors available. By flexibly controlling the number of times for IRS reconfiguring phase-shifts, the system can achieve a balance between the performance and associated signalling overhead. We aim to maximize the sum computation rate by jointly optimizing the computational mode selection for each device, offloading time allocation, and IRS beamforming vectors across time. Since the resulting optimization problem is non-convex and NP-hard, there are generally no standard methods to solve it optimally. To tackle this problem, we first propose a penalty-based successive convex approximation algorithm, where all the associated variables in the inner-layer iterations are optimized simultaneously and the obtained solution is guaranteed to be locally optimal. Then, we further derive the offloading activation condition for each device by deeply exploiting the intrinsic structure of the original optimization problem. According to the offloading activation condition, a low-complexity algorithm based on the successive refinement method is proposed to obtain high-quality suboptimal solutions, which are more appealing for practical systems with a large number of devices and IRS elements. Moreover, the optimal condition for the proposed low-complexity algorithm is revealed. The effectiveness of the proposed algorithms is demonstrated through numerical examples. In addition, the results illustrate the practical significance of the IRS in MEC systems for achieving coverage extension and supporting multiple energy-limited devices for task offloading, and also unveil the fundamental performance-cost tradeoff embedded in the proposed dynamic IRS beamforming framework.

25 January 2022 in IEEE Internet of Things Journal
Verified
Journal Article
Closed access
Chao FangChao Fang
Chao Fang
HXHang Xu
Hang Xu
YYYihui Yang
Yihui Yang
ZHZhaoming Hu
Zhaoming Hu
STShanshan Tu
Shanshan Tu
YLYunjie Liu
Yunjie Liu
With the rapid development of wireless communication technologies, the emerging multimedia applications make mobile Internet traffic grow explosively while putting forward higher service requirements for the next-generation wireless networks. Therefore, how to achieve low-latency content transmission by effectively allocating heterogeneous network resources to improve the network quality of service and end-user quality of experience is a key issue to be solved urgently in the current Internet. In this article, we propose a deep reinforcement learning (DRL)-based resource allocation scheme to improve content distribution in a layered fog radio access network (FRAN). We formulate the optimal resource allocation problem as a minimal delay model, where in-network caching is deployed and the same content requests from mobile users can be aggregated in the queue of each base station. To cope with the increasing user requests and overcome capacity constraints of the FRAN, moreover, a cloud–edge cooperation offloading scheme is utilized in our model, where the integrated allocation of caching, computing, and communication resources and joint optimization between in-network caching and routing are considered to promote resource utilization and content delivery. In our solution, a new DRL policy is designed to make cross-layer cooperative caching and routing decisions for the arriving content requests according to request history information and available network resources in the system. Simulation results demonstrate that our proposed model can performs much better than the existing cloud–edge cooperation schemes in the FRAN.

24 July 2023 in IEEE Transactions on Vehicular Technology
Verified
Journal Article
Closed access
Chao FangChao Fang
Chao Fang
ZHZhaoming Hu
Zhaoming Hu
XMXiangheng Meng
Xiangheng Meng
STShanshan Tu
Shanshan Tu
Zhuwei WangZhuwei Wang
Zhuwei Wang
ZHZhu Han
Zhu Han
With the proliferation of mobile devices (e.g., vehicles and smartphones), rich media content services from massive users lead to high network resource consumption and energy usage. How to effectively allocate heterogeneous network resources and achieve green content delivery is a major challenge to be addressed in urgency, especially when vehicular users are involved and the spatiotemporal distribution of the content requests can change drastically. In this paper, we propose a new deep reinforcement learning (DRL)-aided task offloading and resource allocation scheme, named TORA-DRL, to minimize power consumption in cloud-edge cooperation environments, where in-network caching and request aggregation are incorporated to reduce replicated transmissions of network contents. Based on the history of content requests and available network resources in the system, TORA-DRL jointly optimizes the decisions about task offloading, as well as computing, caching and communication resource allocation, adapting to the changes in network states and user requirements. Simulation results demonstrate that the proposed TORA-DRL solution converges fast and has much higher energy efficiency than the existing popular cloud-edge cooperation schemes under different network environments.

22 February 2021 in IEEE Access
Verified
Journal Article
Open access
HZHongxia Zhang
Hongxia Zhang
YYYongjin Yang
Yongjin Yang
XHXingzhe Huang
Xingzhe Huang
Chao FangChao Fang
Chao Fang
PZPeiying Zhang
Peiying Zhang
With the development of computer technology, computational-intensive and delay-sensitive applications are emerging endlessly, and they are limited by the computing power and battery life of Smart Mobile Devices (SMDs). Mobile edge computing (MEC) is a computation model with great potential to meet application requirements and alleviate burdens on SMDs through computation offloading. However, device mobility and server status variability in the multi-server and multi-task scenario bring challenges to the computation offloading. To cope with these challenges, we first propose a parallel task offloading model and a small area-based edge offloading scheme in MEC. Then, we formulate the optimization problem to minimize the completion time of all tasks, and transform the problem into a deep reinforcement learning-based offloading scheme by Markov decision approach. Furthermore, we present a deep deterministic policy gradient (DDPG) approach for obtaining the offloading strategy. Experimental results demonstrate that the DDPG- based offloading approach improves long-term performance by at least 19% in ultra-low latency, efficient usage of servers, and frequent mobility of SMDs over traditional strategies.

23 May 2022 in IEEE Transactions on Vehicular Technology
Verified
Journal Article
Closed access
Zhuwei WangZhuwei Wang
Zhuwei Wang
SJSenfan Jin
Senfan Jin
LLLihan Liu
Lihan Liu
Chao FangChao Fang
Chao Fang
MLMeng Li
Meng Li
SGSong Guo
Song Guo
Connected cruise control (CCC) refers to a type of advanced driver assistance system combined with wireless vehicle-to-vehicle (V2V) communication technology to improve control stability and driving safety. However, it is urgent to investigate intelligent control algorithms to improve the adaptability of CCC in complex traffic environment. In addition, the effect of communication delays attributed to shared wireless communications on the performance degradation of the intelligent CCC design cannot be ignored. In this study, the design of deep reinforcement learning (DRL) controller for CCC system in high-dynamic traffic scenarios is investigated, which considers both time-varying leading velocity and communication delays. To be more specific, an intelligent CCC algorithm based on deep deterministic policy gradient (DDPG) is developed. According to the training samples obtained from interacting with the traffic environment, the actor network and the critic network are trained to maximize the quadratic reward function determined by state errors and control inputs for generating intelligent control strategies. In particular, the effect of previous control strategies is considered in vehicle dynamics analysis, optimization problem formulation and Markov decision process (MDP) definition to compensate the performance degradation attributed to communication delays. Lastly, the effectiveness and convergence of the proposed DRL-based CCC controller are verified through numerical simulations with various conditions. The superior performance of the proposed algorithm is shown by comparing with existing traditional algorithms and state-of-the-art DRL algorithms.