Junhui Zhao

Prof. Dr. Junhui Zhao

School of Electronic InformationEngineering, Beijing Jiaotong University, Beijing 102603, China
orcid

Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

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

Representative Publications

View All Publications
25 June 2019 in IEEE Transactions on Vehicular Technology
Verified
Journal Article
Closed access
Junhui ZhaoJunhui Zhao
Junhui Zhao
QLQiuping Li
Qiuping Li
YGYi Gong
Yi Gong
KZKe Zhang
Ke Zhang
Computation offloading services provide required computing resources for vehicles with computation-intensive tasks. Past computation offloading research mainly focused on mobile edge computing (MEC) or cloud computing, separately. This paper presents a collaborative approach based on MEC and cloud computing that offloads services to automobiles in vehicular networks. A cloud-MEC collaborative computation offloading problem is formulated through jointly optimizing computation offloading decision and computation resource allocation. Since the problem is non-convex and NP-hard, we propose a collaborative computation offloading and resource allocation optimization (CCORAO) scheme to solve it, and design a distributed computation offloading and resource allocation (DCORA) algorithm for CCORAO scheme that achieves the optimal solution. The simulation results show that the proposed algorithm can effectively improve the system utility and computation time, especially for the scenario where the MEC servers fail to meet demands due to insufficient computation resources.

10 August 2020 in IEEE Transactions on Intelligent Transportation Systems
Verified
Journal Article
Closed access
Junhui ZhaoJunhui Zhao
Junhui Zhao
XSXiaoke Sun
Xiaoke Sun
QLQiuping Li
Qiuping Li
XMXiaoting Ma
Xiaoting Ma
Vehicular Edge Computing (VEC) is expected to be an effective solution to meet the ultra-low delay requirements of many emerging Internet of Vehicles (IoV) services by shifting the service caching and the computation capacities to the network edge. However, due to the constraints of the multidimensional (storage-computing-communication) resources capacities and the cost budgets of vehicles, there are two main issues need to be addressed: 1) How to collaboratively optimize the service caching decision among edge nodes to better reap the benefits of the storage resource and save the time-correlated service reconfiguration cost? 2) How to allocate resources among various vehicles and where vehicular requests are scheduled to improve the efficiency of the computing and communication resources utilization? In this paper, we formulate an edge caching and computation management problem that jointly optimizes the service caching, the request scheduling, and the resource allocation strategies. Our focus is to minimize the time-average service response delay of the random arriving service requests in a cost-efficient way. To cope with the dynamic and unpredictable challenges of IoVs, we leverage the combined power of Lyapunov optimization, matching theory, and consensus alternating direction method of multipliers to solve the problem in an online and distributed manner. Theoretical analysis shows that the developed approach achieves a close-to-optimal delay performance without relying on any prior knowledge of the future network information. Moreover, simulation results validate the theoretical analysis and demonstrate that our algorithm outperforms the baselines substantially.

7 October 2021 in IEEE Transactions on Vehicular Technology
Verified
Journal Article
Closed access
YNYiwen Nie
Yiwen Nie
Junhui ZhaoJunhui Zhao
Junhui Zhao
FGFeifei Gao
Feifei Gao
FYF. Richard Yu
F. Richard Yu
Recently, unmanned aerial vehicle (UAV)-enabled multi-access edge computing (MEC) has been introduced as a promising edge paradigm for the future space-aerial-terrestrial integrated communications. Due to the high maneuverability of UAVs, such a flexible paradigm can improve the communication and computation performance for multiple user equipments (UEs). In this paper, we consider the sum power minimization problem by jointly optimizing resource allocation, user association, and power control in an MEC system with multiple UAVs. Since the problem is nonconvex, we propose a centralized multi-agent reinforcement learning (MARL) algorithm to solve it. However, the centralized method ignores essential issues like distributed framework and privacy concern. We then propose a multi-agent federated reinforcement learning (MAFRL) algorithm in a semi-distributed framework. Meanwhile, we introduce the Gaussian differentials to protect the privacy of all UEs. Simulation results show that the semi-distributed MAFRL algorithm achieves close performances to the centralized MARL algorithm and significantly outperform the benchmark schemes. Moreover, the semi-distributed MAFRL algorithm costs 23 $\%$ lower opeartion time than the centralized algorithm.

18 October 2019 in IEEE Vehicular Technology Magazine
Verified
Journal Article
Closed access
Junhui ZhaoJunhui Zhao
Junhui Zhao
SNShanjin Ni
Shanjin Ni
LYLihua Yang
Lihua Yang
ZZZiyang Zhang
Ziyang Zhang
YGYi Gong
Yi Gong
XYXiaohu You
Xiaohu You

13 January 2023 in IEEE Transactions on Information Forensics and Security
Verified
Journal Article
Closed access
YYYu Yao
Yu Yao
Junhui ZhaoJunhui Zhao
Junhui Zhao
ZLZeqing Li
Zeqing Li
XCXu Cheng
Xu Cheng
LWLenan Wu
Lenan Wu
As a legacy from conventional wireless services, illegal eavesdropping is regarded as one of the critical security challenges in Connected and Autonomous Vehicles (CAVs) network. Our work considers the use of Distributed Kalman Filtering (DKF) and Deep Reinforcement Learning (DRL) techniques to improve anti-eavesdropping communication capacity and mitigate jamming interference. Aiming to improve the security performance against smart eavesdropper and jammer, we first develop a DKF algorithm that is capable of tracking the attacker more accurately by sharing state estimates among adjacent nodes. Then, a design problem for controlling transmission power and selecting communication channel is established while ensuring communication quality requirements of the authorized vehicular user. Since the eavesdropping and jamming model is uncertain and dynamic, a hierarchical Deep Q-Network (DQN)-based architecture is developed to design the anti-eavesdropping power control and possibly channel selection policy. Specifically, the optimal power control scheme without prior information of the eavesdropping behavior can be quickly achieved first. Based on the system secrecy rate assessment, the channel selection process is then performed when necessary. Simulation results confirm that our jamming and eavesdropping defense technique enhances the secrecy rate as well as achievable communication rate compared with currently available techniques.

22 April 2020 in IEEE Communications Letters
Verified
Journal Article
Closed access
JLJieyu Liao
Jieyu Liao
Junhui ZhaoJunhui Zhao
Junhui Zhao
FGFeifei Gao
Feifei Gao
GLGeoffrey Ye Li
Geoffrey Ye Li
In this paper, an efficient massive multiple-input multiple-output (MIMO) detector is proposed by employing a deep neural network (DNN). Specifically, we first unfold an existing iterative detection algorithm into the DNN structure, such that the detection task can be implemented by deep learning (DL) approach. We then introduce two auxiliary parameters at each layer to better cancel multiuser interference (MUI). The first parameter is to generate the residual error vector while the second one is to adjust the relationship among previous layers. We further design the training procedure to optimize the auxiliary parameters with pre-processed inputs. The so derived MIMO detector falls into the category of model-driven DL. The simulation results show that the proposed MIMO detector can achieve preferable detection performance compared to the existing detectors for massive MIMO systems.