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Multi-Channel Spectrum Sensing in Cognitive Ad-hoc networks:An Energy-Efcient Manner

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Journal of Shanghai Jiaotong university(Science) 2013年第5期18卷 513-519页

作者：李鹤甘小莺陈时阳冯心欣 Department of Electronic Engineering Shanghai Jiaotong University State Key Laboratory of Integrated services networks Xidian University

Cognitive radio,which is capable of enabling dynamic spectrum access,is a promising technology in future wireless *** feasibility of cognitive radio network greatly depends on the energy efciency and reliability of spectrum sensing *** this paper,spectrum sensing in cognitive ad-hoc network(CAN)with wide-band dynamic spectrum is considered.A cognitive cluster head(CCH)is set and responsible for dividing the wide-band spectrum into multiple sub-channels;it can either sense sub-channels in a centralized manner,or make use of sensing modules to sense sub-channels in a distributed *** cognitive users(CUs)can get sensing results and access to the available *** take the cost of control message into consideration and formulate the energy consumption of CAN in terms of sub-channel sampling rate and whole-band sensing *** define energy efciency intuitively and solve the energy efciency optimization problem with sensing reliability constraints by constructing a parametric problem and obtain the optimal sampling rate and the wholeband sensing *** dissipation model of a practical A/D convertor(ADC)is introduced,and numerical results are given to show the energy efciency performance of two diferent sensing manners.

关键词： cognitive radio spectrum sensing energy efciency ad-hoc network multi-channel

A Distributed Self-Tallying Electronic Voting System Using the Smart Contract

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Chinese Journal of Electronics 2024年第4期33卷 1063-1076页

作者： Jingyu YAO Bo YANG Tao WANG Wenzheng ZHANG School of Computer Science Shaanxi Normal University State Key Laboratory of Integrated services networks Xidian University Science and Technology on Communication Security Laboratory

For electronic voting(e-voting) with a trusted authority, the ballots may be discarded or tampered, so it is attractive to eliminate the dependence on the trusted party. An e-voting protocol, where the final voting result can be calculated by any entity, is known as self-tallying e-voting protocol. To the best of our knowledge, addressing both abortive issue and adaptive issue simultaneously is still an open problem in self-tallying e-voting *** Ethereum blockchain with cryptographic technologies, we present a decentralized self-tallying e-voting protocol. We solve the above problem efficiently by utilizing optimized Group Encryption Scheme and standard Exponential El Gamal Cryptosystem. We use zero-knowledge proof and homomorphic encryption to protect votes' secrecy and achieve self-tallying. All ballots can be verified by anyone and the final voting result can be calculated by any entity. In addition, using the paradigm of score voting and “1-out-of-k” proof, our e-voting system is suitable for a wide range of application scenarios. Experiments show that our protocol is more competitive and more suitable for large-scale voting.

关键词： Electronic voting systems Smart contracts Blockchains Cryptocurrency Electronic voting Homomorphic encryption Standards

Fair relay selection in decode-and-forward cooperation based on outage priority

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Science China(Information Sciences) 2013年第6期56卷 5-14页

作者： LI YuBo WANG HuiMing YIN QinYe LUO Miao School of Electronic and Information Engineering Xi'an Jiaotong University State Key Laboratory of Integrated services networks Xidian University Ministry of Education Key Lab for Intelligent networks and Network Security Xi'an Jiaotong University

The opportunistic cooperation schemes,where only the "best" relay is selected to forward the message,have been widely investigated recently for their good performance in terms of outage ***,the unfair selections of relays may cause unbalance power consumptions among relays,which reduces the lifetime of energy constrained *** this paper,we introduce a novel concept of outage priority based fairness(OPF),aiming at improving the selection fairness among relays appropriately without outage performance ***,a cooperation scheme is proposed to meet this concept,and corresponding theoretical analysis is also ***,based on OPF,the achievable upper bound of the fairness is derived,and an optimal cross-layer designed scheme is also provided to achieve the *** simulations are carried out finally,which not only validate the theoretical analysis,but also show that taking advantages of the proposed schemes,the fairness among all relays,as well as the network lifetime,can be greatly improved without any loss of outage performance,especially in high SNR regime.

关键词： cooperative diversity relay fairness opportunistic cooperation outage probability

Performance Analysis for Amplify-and-Forward Relay Selection with Outdated Channel State Information

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China Communications 2013年第6期10卷 100-110页

作者：钟斌张中山皇甫伟王军隆克平 Institute of advanced Network Technology and New services(ANTS) and Beijing Engineering and Technology Research Center for Convergence networks and Ubiquitous services University of Science and Technology Beijing

The impact of outdated Channel State Information(CSI) on the performance of relay selections,including the partial relay selection and the best relay selection,is studied,with respect to Amplify-and-Forward(AF) mode cooperative *** proposed method is analysed by deriving the asymptotic closedform expressions for some figures of merit such as the outage probability and the Symbol Error Probability(SEP).Moreover,the validity of the proposed theoretical analysis is proven via *** results prove that the performance of the proposed scheme is impacted considerably by various parameters such as the number of candidate relays and the end-to-end Signal-to-Noise Ratio(SNR).In the presence of cooperative networks with outdated CSI feedback,a performance improvement of more than 3 dB in terms of either outage probability or SEP can be observed by utilizing the Source-to-Destination(S D) link rather than the method of simply increasing the number of relays.

关键词： relays AF outage probability SEP outdated CSI cooperative systems

Doppler Spectrum Analysis of Time-Evolving Sea Surface Covered by Oil Spills

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Chinese Physics Letters 2015年第4期32卷 45-48页

作者：杨鹏举郭立新贾春刚 School of Physics and Optoelectronic Engineering Xidian University Xi'an 710071 State Key Laboratory of Integrated services networks Xidian University Xi'an 710071

Based on the model of a contaminated sea surface that was proposed by Lombardini et al., the influence of the damping effect of oil films on the sea surface roughness spectrum and the geometrical structure of the sea surface is examined in detail by comparing with a clean sea surface. Fhrthermore, based on a quasi-stationary algorithm, a time series of backscattered echoes from a time-evolving sea surface covered by oil slicks is obtained by utilizing the frequency-domain numerical method of the parallel fast multiple method. Then, the Doppler spectrum is evaluated by performing a standard spectral estimation technique. Finally, the influence of the oil film damping effect on the Doppler spectrum of the backscattered echoes from time-evolving sea surface is investigated in detail by making a comparison of the Doppler spectrum of an oil-covered sea surface with the Doppler spectrum of a dean sea surface. The numerical simulations show that the damping effect of oil films has an influence on the Doppler spectrum signature for both horizontal-to-horizontal and vertical-to-vertical polarizations.

关键词： Doppler Spectrum Analysis of Time-Evolving Sea Surface Covered by Oil Spills

Resource Allocation in Multi-User Cellular networks:A Transformer-Based Deep Reinforcement Learning Approach

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China Communications 2024年第5期21卷 77-96页

作者： Zhao Di Zheng Zhong Qin Pengfei Qin Hao Song Bin State Key Laboratory of Integrated services networks Xidian University710071China China Academy of Space Technology Beijing 100081China

To meet the communication services with diverse requirements,dynamic resource allocation has shown increasing *** this paper,we consider the multi-slot and multi-user resource allocation(MSMU-RA)in a downlink cellular scenario with the aim of maximizing system spectral efficiency while guaranteeing user *** first model the MSMURA problem as a dual-sequence decision-making process,and then solve it by a novel Transformerbased deep reinforcement learning(TDRL)***,the proposed TDRL approach can be achieved based on two aspects:1)To adapt to the dynamic wireless environment,the proximal policy optimization(PPO)algorithm is used to optimize the multi-slot RA strategy.2)To avoid co-channel interference,the Transformer-based PPO algorithm is presented to obtain the optimal multi-user RA scheme by exploring the mapping between user sequence and resource *** results show that:i)the proposed approach outperforms both the traditional and DRL methods in spectral efficiency and user fairness,ii)the proposed algorithm is superior to DRL approaches in terms of convergence speed and generalization performance.

关键词： dynamic resource allocation multi-user cellular network spectrum efficiency user fairness

Iterative Noncoherent Block Detection of Coded MPSK for Cooperative Relay Systems

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China Communications 2016年第7期13卷 1-6页

作者： Yucheng He Jingjing Zhang Rui Zhao Lin Zhou Xiamen Key Laboratory of Mobile Multimedia Communications National Huaqiao University State Key Laboratory of Integrated services networks Xidian University

Maximum likelihood(ML) noncoherent block detection techniques are investigated for block-coded MPSK modulation in cooperative decode-and-forward relay systems over slow fading channels.A decision-directed iterative Viterbi algorithm(IVA) is derived for a suboptimal ML noncoherent *** results show that the IVA can approach the error performances of the exhaustive detection method but at a lower complexity.

关键词： Coded modulation cooperative communication M-ray phase shift keying noncoherent detection

A Mutual Evaluation Based Trust Management Method for Wireless Sensor networks

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Chinese Journal of Electronics 2017年第2期26卷 407-415页

作者： GUO Jingjing MA Jianfeng WAN Tao School of Cyber Engineering Xidian University The State Key Laboratory of Integrated services networks Xidian University School of Information Engineering East China Jiaotong University

We propose a lightweight trust system for the clustered wireless sensor networks based on the mutual evaluation between the cluster heads and sensor *** evaluate the trust level of a cluster head in two aspects,namely,trust level as a service provider and a *** consider multidimensional trust attributes to compute the global trust value of a *** means of the Petri net(PN),we illustrate the performance of an entity in our trust *** analyses as well as simulations are done and the results showed that our model with linear computational complexity had less memory and communication overhead when compared with the current state-ofart trust management *** addition,our model can detect malicious and selfish entities(especially the malicious cluster head) and resist various attacks efficiently.

关键词： Trust management Petri nets(PNs) Clustered wireless sensor networks

Physical layer security via maximal ratio combining and relay selection over Rayleigh fading channels

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Science China(Information Sciences) 2016年第6期59卷 167-176页

作者： Bin ZHONG Minggang WU Tong LI Zhongshan ZHANG School of Information and Electrical Engineering Hunan University of Science and Technology Beijing Engineering and Technology Center for Convergence networks and Ubiquitous services University of Science and Technology Beijing

In this paper, the impact of both maximal ratio combining(MRC) and relay selection on the physical layer security in wireless communication systems is investigated by analyzing critical issues such as the probability characteristics of the legitimate receiver(Bob) and malicious eavesdropper(Eve)’s end-to-end signal-to-noise ratio(SNR), the secrecy outage probability and the average secrecy channel capacity over Rayleigh fading Channel, etc. Unlike the conventional physical layer security schemes, we assume that Bob receives its data from both the relay and the source via cooperative relay, provided that MRC is employed at the ***, compared to the conventional MRC methods, the proposed method is capable of achieving a higher spatial diversity order by performing relay selection, as validated by performing the theoretical analysis as well as numerical simulation. Furthermore, the closed-form expressions in terms of secrecy outage probability and average secrecy capacity are all consistent with the numerical results. Finally, the proposed scheme may be substantially affected by a number of parameters such as the number of relays, the SNR of links and the ratio of main-to-eavesdropper ratio(MER) λME.

关键词： average secrecy capacity cooperative communication maximal ratio combining outage probability physical layer security