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Joint 3D Trajectory and Resource Optimization for A UAV Relay-Assisted Cognitive Radio Network

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China Communications 2021年第6期18卷 184-200页

作者： Zhen Wang Fuhui Zhou Yuhao Wang qihui wu School of Artificial Intelligence Beijing University of Posts and TelecommunicationsBeijing 100876China School of Information Engineering Nanchang UniversityNanchang 330031China Nanjing University of Aeronautics and Astronautics Nanjing211106China Shaanxi Key Laboratory of Information Communication Network and Security Xi’an University of Posts and TelecommunicationXi’an710061China

In this paper,we consider a new spectrum sharing scenario for a cognitive relay network,where a secondary unmanned aerial vehicle(UAV)relay receives information from the ground secondary base station(SBS)and transmits information to the ground secondary user(SU),coexisting with the primary users(PUs)at the same wireless frequency *** investigate the optimization of the UAV relay’s three-dimensional(3D)trajectory to improve the communication throughput performance of the secondary network subject to the interference constraints of the *** information throughput maximization problem is studied by jointly optimizing the UAV relay’s 3D trajectory and the transmit power of the SBS and the UAV,subject to the constraints on the velocity and elevation of the UAV relay,the maximum and average transmit power,and the information causality,as well as a set of interference temperature(IT)*** efficient algorithm is proposed to solve the admittedly challenging non-convex problem by using the path discretization technique,the successive convex approximation technique and the alternating optimization ***,simulation results are provided to show that our proposed design outperforms other benchmark schemes in terms of the throughput。

关键词： cognitive radio UAV communication 3D trajectory design mobile relaying power allocation

Graph neural network-based scheduling for multi-UAV-enabled communications in D2D networks

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Digital Communications and Networks 2024年第1期10卷 45-52页

作者： Pei Li Lingyi Wang Wei wu Fuhui Zhou Baoyun Wang qihui wu Nanjing University of Posts and Telecommunications Nanjing210023China Nanjing University of Aeronautics and Astronautics Nanjing210016China

In this paper,we jointly design the power control and position dispatch for Multi-Unmanned Aerial Vehicle(UAV)-enabled communication in Device-to-Device(D2D)*** objective is to maximize the total transmission rate of Downlink Users(DUs).Meanwhile,the Quality of Service(QoS)of all D2D users must be *** comprehensively considered the interference among D2D communications and downlink *** original problem is strongly non-convex,which requires high computational complexity for traditional optimization *** to make matters worse,the results are not necessarily globally *** this paper,we propose a novel Graph Neural Networks(GNN)based approach that can map the considered system into a specific graph structure and achieve the optimal solution in a low complexity ***,we first construct a GNN-based model for the proposed network,in which the transmission links and interference links are formulated as vertexes and edges,***,by taking the channel state information and the coordinates of ground users as the inputs,as well as the location of UAVs and the transmission power of all transmitters as outputs,we obtain the mapping from inputs to outputs through training the parameters of *** results verified that the way to maximize the total transmission rate of DUs can be extracted effectively via the training on ***,it also shows that the performance of proposed GNN-based method is better than that of traditional means.

关键词： Unmanned aerial vehicle D2 Dcommunication Graph neural network Power control Position planning

Edge Semantic Cognitive Intelligence for 6G Networks:Novel Theoretical Models,Enabling Framework,and Typical Applications

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China Communications 2022年第8期19卷 1-14页

作者： Peihao Dong qihui wu Xiaofei Zhang Guoru Ding The Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space Ministry of Industry and Information TechnologyCollege of Electronic and Information EngineeringNanjing University of Aeronautics and AstronauticsNanjing 211106China College of Communications Engineering Army Engineering UniversityNanjing 210007China

Edge intelligence is anticipated to underlay the pathway to connected intelligence for 6G networks,but the organic confluence of edge computing and artificial intelligence still needs to be carefully *** this end,this article discusses the concepts of edge intelligence from the semantic cognitive *** instructive theoretical models for edge semantic cognitive intelligence(ESCI)are first ***,the ESCI framework orchestrating deep learning with semantic communication is *** representative applications are present to shed light on the prospect of ESCI in 6G *** open problems are finally listed to elicit the future research directions of ESCI.

关键词： edge intelligence semantic communication and cognition deep neural network semantic information theory

Turbo iterative equalization for HSDPA systems

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Science in China(Series F) 2007年第1期50卷 105-112页

作者： wu qihui ZHAO ChunMing WANG JinLong Department of Radio Engineering Southeast University Nanjing 210096 China Institute of Communications Engineering Nanjing 210007 China

in this paper, a turbo Iterstive receiver structure with chip equalization is proposed for the 3G high-speed downllnk packet access （HSDPA） systems. The receiver equalizes the channel prior to the dlspreadlng and then performs two successive soft-output decisions, achieved by s soft-Input soft-output （SISO） multi-code detector and a SISO turbo decoder through an Iteratlve process. At each Iteration, extrinsic information Is extracted from detection and decoding stages and Is then used as a priori Information In the next Iteration, Just as In turbo decoding. Computer simulations show that the turbo Iterstlve receiver structure with chip equsllzation offers significant performance gain over the traditional receiver structure.

关键词： chip equalization HSDPA multi-code detection turbo code turbo processing

Intelligent reflecting surface assisted untrusted NOMA transmissions: a secrecy perspective

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Science China(Information Sciences) 2023年第9期66卷 226-238页

作者： Dawei WANG Xuanrui LI Yixin HE Fuhui ZHOU qihui wu School of Electronics and Information Northwestern Polytechnical University Research & Development Institute of Northwestern Polytechnical University in Shenzhen College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space Nanjing University of Aeronautics and Astronautics

In this paper, we investigate the intelligent reflecting surface(IRS) assisted secure transmissions for the untrusted non-orthogonal multiple access(NOMA) network threatened by an external eavesdropper,where the near user and two untrusted far users receive the privacy information from the transmitter assisted by the IRS’s passive reflection. To protect the privacy information against internal and external eavesdropping, we first provide a comprehensive analysis of the secrecy rates, which can offer suitable methods for separately handling the internal and external secrecy performance. Following the above results, we formulate a secrecy rate maximization problem by optimizing the transmission power allocation and phase shifts. To achieve this goal, we decouple the non-convex optimization problem into the external security problem and the internal security problem. Then, we propose a heuristic simulated annealing algorithm to iteratively solve the above problems, where the semi-definite relaxation(SDR) technique, the singular value decomposition(SVD) technique, and the Lagrange multiplier method are utilized to relax the problems and optimize the power allocation and phase shifts. Finally, numerical results show that the proposed scheme can improve the secrecy rate compared with the existing IRS-aided secure NOMA transmission schemes.

关键词： intelligent reflecting surface non-orthogonal multiple access security untrusted users.

Joint Task Allocation and Resource Optimization for Blockchain Enabled Collaborative Edge Computing

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China Communications 2024年第12期21卷 218-229页

作者： Xu Wenjing Wang Wei Li Zuguang wu qihui Wang Xianbin College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space Ministry of Industry and Information TechnologyNanjing 211106China Department of Electrical and Computer Engineering Western UniversityCanada

Collaborative edge computing is a promising direction to handle the computation intensive tasks in B5G wireless ***,edge computing servers(ECSs)from different operators may not trust each other,and thus the incentives for collaboration cannot be *** this paper,we propose a consortium blockchain enabled collaborative edge computing framework,where users can offload computing tasks to ECSs from different *** minimize the total delay of users,we formulate a joint task offloading and resource optimization problem,under the constraint of the computing capability of each *** apply the Tammer decomposition method and heuristic optimization algorithms to obtain the optimal ***,we propose a reputation based node selection approach to facilitate the consensus process,and also consider a completion time based primary node selection to avoid monopolization of certain edge node and enhance the security of the *** results validate the effectiveness of the proposed algorithm,and the total delay can be reduced by up to 40%compared with the non-cooperative case.

关键词： blockchain collaborative edge computing resource optimization task allocation

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Joint Task Scheduling, Resource Allocation, and UAV Trajectory under Clustering for FANETs

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China Communications 2022年第1期19卷 104-118页

作者： Wenjing You Chao Dong qihui wu Yuben Qu Yulei wu Rong He The Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing 211106China AVIC Chengdu Aircraft Design and Research Institute China

This paper establishes a new layered flying ad hoc networks(FANETs) system of mobile edge computing(MEC) supported by multiple UAVs,where the first layer of user UAVs can perform tasks such as area coverage, and the second layer of MEC UAVs are deployed as flying MEC sever for user UAVs with computing-intensive tasks. In this system, we first divide the user UAVs into multiple clusters, and transmit the tasks of the cluster members(CMs) within a cluster to its cluster head(CH). Then, we need to determine whether each CH’ tasks are executed locally or offloaded to one of the MEC UAVs for remote execution(i.e., task scheduling), and how much resources should be allocated to each CH(i.e., resource allocation), as well as the trajectories of all MEC *** formulate an optimization problem with the aim of minimizing the overall energy consumption of all user UAVs, under the constraints of task completion deadline and computing resource, which is a mixed integer non-convex problem and hard to solve. We propose an iterative algorithm by applying block coordinate descent methods. To be specific, the task scheduling between CH UAVs and MEC UAVs, computing resource allocation, and MEC UAV trajectory are alternately optimized in each iteration. For the joint task scheduling and computing resource allocation subproblem and MEC UAV trajectory subproblem, we employ branch and bound method and continuous convex approximation technique to solve them,respectively. Extensive simulation results validate the superiority of our proposed approach to several benchmarks.

关键词： flying ad hoc networks(FANETs) successive convex approximation clustering mobile edge computing(MEC)

Blockchain-Empowered Dynamic Spectrum Management for Space-Air-Ground Integrated Network

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Chinese Journal of Electronics 2022年第3期31卷 456-466页

作者： LI Zuguang WANG Wei GUO Jia ZHU Youwen HAN Lu wu qihui College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space Ministry of Industry and Information Technology

Space-air-ground integrated network is capable of providing seamless and ubiquitous services to cater for the increasing wireless communication demands of emerging applications. However, how to efficiently manage the heterogeneous resources and protect the privacy of connected devices is a very challenging issue, especially under the highly dynamic network topology and multiple trustless network operators. In this paper, we investigate blockchain-empowered dynamic spectrum management by reaping the advantages of blockchain and software defined network(SDN), where operators are incentive to share their resources in a common resourced pool. We first propose a blockchain enabled spectrum management framework for space-air-ground integrated network, with inter-slice spectrum sharing and intra-slice spectrum allocation. Specifically, the inter-slice spectrum sharing is realized through a consortium blockchain formed by the upper-tier SDN controllers, and then a graph coloring based channel assignment algorithm is proposed to manage the intra-slice spectrum assignment. A bilateral confirmation protocol and a consensus mechanism are also proposed for the consortium blockchain. The simulation results prove that our proposed consensus algorithm takes less time than practical Byzantine fault tolerance algorithm to reach a consensus, and the proposed channel assignment algorithm significantly improves the spectrum utilization and outperforms the baseline algorithm in both simulation and real-world scenarios.

关键词： consensus mechanism space communication links blockchains blockchain-empowered dynamic spectrum management radio spectrum management multiple trustless network operators wireless communication demands graph coloring software defined networking inter-slice spectrum sharing graph colouring upper-tier SDN controllers fault tolerant computing protocols Byzantine fault tolerance algorithm spectrum utilization space-air-ground integrated network channel allocation software defined network channel assignment algorithm consortium blockchain intra-slice spectrum assignment intra-slice spectrum allocation telecommunication network topology highly dynamic network topology

Eliminating Explicit Contention from Channel Access in Distributed Wireless Networks

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China Communications 2019年第5期16卷 70-82页

作者： Aijing Li Chao Dong Fan wu Shaojie Tang Guihai Chen qihui wu Department of Computer Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China College of Communications Engineering PLA Army Engineering UniversityNanjing 210007China College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China Department of Information Systems University of Texas at DallasTexas 75080USA

Emerging techniques such as WiFi direct makes the objective of always-on be true. People can easily chat and share files with nearby friends even without AP(Access Point) or cellular coverage. In this paper, we focus on the channel efficiency issue of APfree Wi-Fi networks, which can be easily constructed in the subway, in a high-speed railway, or when camping in the wild. Today IEEE 802.11 DCF is the most commonly used MAC protocol for Wi-Fi networks, however, due to the control messages and backoff time, channel efficiency in high data rate networks can be extremely low. To solve this, we propose CD-MAC, which allows control messages to be transmitted with data packets concurrently, and thus eliminates the overheads of backoff and explicit contention. To maintain the reception reliability, we redesign the control messages and use signal detection in PHY instead of bits decoding to detect them. In MAC layer, CD-MAC is built upon our Correlation Detection based PHY. We have implemented and evaluated CD-MAC using USRP N210. Evaluation results show that CD-MAC can achieve over 95.5% channel efficiency and provide throughput gains of up to 80%, 60%, and 29.1% compared with DCF, 802.11 ec, and back2F, respectively.

关键词： implicit contention correlation detection media access ad hoc networks OFDM USRP