Unmanned aerial vehicle(UAV)communication has attracted wide attentions in the mobile edge computing(MEC)system owing to its high-flexibility and simple operation auxiliary communication mode.Users can offload computi...Unmanned aerial vehicle(UAV)communication has attracted wide attentions in the mobile edge computing(MEC)system owing to its high-flexibility and simple operation auxiliary communication mode.Users can offload computing tasks to UAVs,which serves as edge nodes.Meanwhile,UAVs forward the tasks onto a cloud center or base station for processing,thereby shortening the implementation time of tasks.Nevertheless,the offloading links of an UAV-assisted MEC system adopt a radio broadcasting mode.Several eavesdroppers might be present in the environment to eavesdrop the data sent by users and UAVs,thereby causing significant effects on the secrecy performance.An optimized iterative algorithm is proposed in this paper to realize the maximum secrecy capacity of the MEC system and further improve the secrecy performance of an UAV-assisted MEC system and assure secrecy transmit.By doing so,the secrecy transmit problems of the two-staged offloading model of the UAV-assisted MEC system are solved.The maximum secrecy capacity of the system is obtained through joint optimization of the UAV positions,transmit power of the UAV,task offloading ratio,and allocation of offloading users considering the limited time and energy of an UAV.Simulation results demonstrate that the proposed iterative algorithm can effectively improve the secrecy capacity of the system.展开更多
In this paper, a weighted fractional Fourier transform(WFRFT) based cooperative overlay system, aiming to guarantee physical layer(PHY) security, is proposed. The paper elaborates how WFRFT and physical layer properti...In this paper, a weighted fractional Fourier transform(WFRFT) based cooperative overlay system, aiming to guarantee physical layer(PHY) security, is proposed. The paper elaborates how WFRFT and physical layer properties of the wireless medium are collaborated to guarantee the secrecy of wireless transmissions. In the proposed system, WFRFT is first preform on the secret data, such that the transmitted signal is distorted and can only be neutralized by inverse-WFRFT with the same parameter. And then two streams of the transformed sequences that bearing different messages are cooperatively and simultaneously transmitted to two legitimate receivers via a beamforming-liked method, respectively. In general, both the rapid spatial decorrelation property and the inherent security features of WFRFT are leveraged, such that only the eavesdropper's is degraded, and hence, the wireless communication secrecy is reliably guaranteed. Numerical simulations are conducted to evaluate the performance of the proposed system in terms of the average bit error rate and the secrecy capacity.展开更多
We study the impact of various modulation mapping strategies and signal constellation shapes on the se- crecy rates achievable with bit-interleaved coded modulation （BICM） schemes. Transmission over an ergodic Rayle...We study the impact of various modulation mapping strategies and signal constellation shapes on the se- crecy rates achievable with bit-interleaved coded modulation （BICM） schemes. Transmission over an ergodic Rayleigh fading channel is assumed throughout this work. Various constellations and mapping techniques are considered in this work to maximize the capacity difference between the main channel and the eavesdropper channel, rather than to opti- mize the capacity of both channels. We show that in terms of achievable secrecy rate, Gray and Quasi-Gray mappings only perform Well at low SNR but outperformed by other mapping techniques when SNR increases. The proper design of signal mapping can significantly enhance the achievable secrecy rate in BICM schemes. It is indicated that the key parameter to the secrecy rate of a BICM system is the distance spectrum of Euclidean distances for mappings.展开更多
The co-channel interference modeling is vital for evaluating the secrecy performance in random wireless networks,where the legitimate nodes and eavesdroppers are randomly distributed.In this paper,a new interference m...The co-channel interference modeling is vital for evaluating the secrecy performance in random wireless networks,where the legitimate nodes and eavesdroppers are randomly distributed.In this paper,a new interference model is proposed from the userdominant perspective.The model can provide a better analytical assessment of secrecy performance with interference coordination for the presence of eavesdroppers.The typical legitimate is assumed to be located at the origin,and chooses the closest base station(BS) as its serving BS.The field of interferers is obtained by excluding the desired BSs(including the serving BS and its cooperative BS(s)).In contract with the exiting interference model,it is assumed that desired BSs and interferers belong to the same Poisson Point Process(PPP),and eavesdroppers are distributed according to another independent PPP.Based on this model,the average secrecy transmission capacity is derived in simply analytical forms with interference coordination.Analysis and simulation results show that the secrecy performance can be significantly enhanced by exploiting interference coordination.Furthermore,the average secrecy transmission capacity increases with increasing number of cooperative BSs.展开更多
Cloud computing is always adopted to enhance the computing capability of mobile systems, especially when the mobile users prefer to use some computation intensive applications. Consequently, the distributed wireless r...Cloud computing is always adopted to enhance the computing capability of mobile systems, especially when the mobile users prefer to use some computation intensive applications. Consequently, the distributed wireless relay infrastructure should be deployed to aid the traffic transmission. To further enhance the QoS provisioning goals of wireless cooperative network, this paper puts forward a multi-objective approach for distributed optimal relay selection, which takes Bit Error Rate (BER) and Secrecy Capacity (SC) into account simultaneously. Firstly, our proposal partitions the channel state into several levels according to the received signal-to-noise ratio (SNR) and describes the time-varying Rayleigh fading channel characteristics by using first order finite-state Markov model. Secondly, we model the relay selection as Restless Multi-armed Bandit optimal solution problem with respect to the channel state and the state transition probability. Finally, simulation results demonstrate the efficiency of the proposed approach which outperforms the existing ones.展开更多
This work investigates the security issue of the energy-constrained untrusted relay network with imperfect channel reciprocity,where the relay without the built-in power supply can only scavenge energy from radio-freq...This work investigates the security issue of the energy-constrained untrusted relay network with imperfect channel reciprocity,where the relay without the built-in power supply can only scavenge energy from radio-frequency signals radiated by the source and destination.A hybrid power-splitting(PS)-and time-switching(TS)-based relaying(HPTR)protocol is presented to improve the degraded secrecy performance due to the incomplete self-interference cancellation at the destination.To evaluate the secrecy throughput(ST)of the studied system,the analytical expression of the secrecy outage probability under the delay-limited transmission mode and the closed-form lower bound of the ergodic secrecy capacity under delay-tolerant transmission mode are derived.Both linear and nonlinear models for the energy harvester at the relay are compared.The optimal PS and TS ratios are evaluated numerically.The theoretical derivations are validated by numerical results,revealing that the residual jamming has a negative effect on the secrecy performance of untrusted relay networks,which can be alleviated by the HPTR protocol.Besides,we compare the ST performance of the HPTR protocol with that of the PS and TS relaying schemes,and the results show that the HPTR protocol outperforms both PS and TS relaying protocols in terms of the ST.展开更多
Abstract：Aiming at achieving better Quality of Service （QoS） provisioning in distributed wireless cooperative networks, a novel energy efficient jammer selection approach is proposed in this pa per. We employ Secre...Abstract：Aiming at achieving better Quality of Service （QoS） provisioning in distributed wireless cooperative networks, a novel energy efficient jammer selection approach is proposed in this pa per. We employ Secrecy Capacity （SC） to charac terize the security of transmission. In order to ac curately describe the timevarying characteristic, related channels are modeled as FiniteState M ark ov Channels （FSMCs）. The remaining energy of candidate node is considered in a similar way.展开更多
With increasing the demand for transmitting secure information in wireless networks,deviceto-device(D2D)communication has great potential to improve system performance.As a well-known security risk is eavesdropping in...With increasing the demand for transmitting secure information in wireless networks,deviceto-device(D2D)communication has great potential to improve system performance.As a well-known security risk is eavesdropping in D2D communication,ensuring information security is quite challenging.In this paper,we first obtain the closed-forms of the secrecy outage probability(SOP)and the secrecy ergodic capacity(SEC)for direct and decodeand-forward(DF)relay modes.Numerical results are presented to verify the theoretical results,and these results show the cases that the DF relay mode improves security performance compared to the direct mode at long distances between the transmitter and receiver nodes.Further,we look into the optimization problems of secure resource allocation in D2D communication to maximize the SEC and to minimize the SOP by considering the strictly positive secrecy capacity constraint as a mixed-integer non-linear programming(MINLP)problem.In the continue,we convert the MINLP to convex optimization.Finally,we solve this program with a dual method and obtain an optimal solution in the direct and DF relay modes.展开更多
基金the National Natural Science Foundation of China(No.61771195)The Natural Science Foundation of Hebei Province(No.F2018502047)The Fundamental Research Funds for the Central Universities(No.2020MS098).
文摘Unmanned aerial vehicle(UAV)communication has attracted wide attentions in the mobile edge computing(MEC)system owing to its high-flexibility and simple operation auxiliary communication mode.Users can offload computing tasks to UAVs,which serves as edge nodes.Meanwhile,UAVs forward the tasks onto a cloud center or base station for processing,thereby shortening the implementation time of tasks.Nevertheless,the offloading links of an UAV-assisted MEC system adopt a radio broadcasting mode.Several eavesdroppers might be present in the environment to eavesdrop the data sent by users and UAVs,thereby causing significant effects on the secrecy performance.An optimized iterative algorithm is proposed in this paper to realize the maximum secrecy capacity of the MEC system and further improve the secrecy performance of an UAV-assisted MEC system and assure secrecy transmit.By doing so,the secrecy transmit problems of the two-staged offloading model of the UAV-assisted MEC system are solved.The maximum secrecy capacity of the system is obtained through joint optimization of the UAV positions,transmit power of the UAV,task offloading ratio,and allocation of offloading users considering the limited time and energy of an UAV.Simulation results demonstrate that the proposed iterative algorithm can effectively improve the secrecy capacity of the system.
基金supported by the National Basic Research Program of China under Grant 2013CB329003the National Natural Science Founda-tion General Program of China under Grant 61171110
文摘In this paper, a weighted fractional Fourier transform(WFRFT) based cooperative overlay system, aiming to guarantee physical layer(PHY) security, is proposed. The paper elaborates how WFRFT and physical layer properties of the wireless medium are collaborated to guarantee the secrecy of wireless transmissions. In the proposed system, WFRFT is first preform on the secret data, such that the transmitted signal is distorted and can only be neutralized by inverse-WFRFT with the same parameter. And then two streams of the transformed sequences that bearing different messages are cooperatively and simultaneously transmitted to two legitimate receivers via a beamforming-liked method, respectively. In general, both the rapid spatial decorrelation property and the inherent security features of WFRFT are leveraged, such that only the eavesdropper's is degraded, and hence, the wireless communication secrecy is reliably guaranteed. Numerical simulations are conducted to evaluate the performance of the proposed system in terms of the average bit error rate and the secrecy capacity.
文摘We study the impact of various modulation mapping strategies and signal constellation shapes on the se- crecy rates achievable with bit-interleaved coded modulation （BICM） schemes. Transmission over an ergodic Rayleigh fading channel is assumed throughout this work. Various constellations and mapping techniques are considered in this work to maximize the capacity difference between the main channel and the eavesdropper channel, rather than to opti- mize the capacity of both channels. We show that in terms of achievable secrecy rate, Gray and Quasi-Gray mappings only perform Well at low SNR but outperformed by other mapping techniques when SNR increases. The proper design of signal mapping can significantly enhance the achievable secrecy rate in BICM schemes. It is indicated that the key parameter to the secrecy rate of a BICM system is the distance spectrum of Euclidean distances for mappings.
基金This work is supported by the National Natural Science Foundation for Distinguished Young Scholar of China under Grant No. 61325006 and the National High-tech Research and Development Program of China under Grant No. 2014AA01A701.
文摘The co-channel interference modeling is vital for evaluating the secrecy performance in random wireless networks,where the legitimate nodes and eavesdroppers are randomly distributed.In this paper,a new interference model is proposed from the userdominant perspective.The model can provide a better analytical assessment of secrecy performance with interference coordination for the presence of eavesdroppers.The typical legitimate is assumed to be located at the origin,and chooses the closest base station(BS) as its serving BS.The field of interferers is obtained by excluding the desired BSs(including the serving BS and its cooperative BS(s)).In contract with the exiting interference model,it is assumed that desired BSs and interferers belong to the same Poisson Point Process(PPP),and eavesdroppers are distributed according to another independent PPP.Based on this model,the average secrecy transmission capacity is derived in simply analytical forms with interference coordination.Analysis and simulation results show that the secrecy performance can be significantly enhanced by exploiting interference coordination.Furthermore,the average secrecy transmission capacity increases with increasing number of cooperative BSs.
基金supported by National Natural Science Foundation of China under Grant No.60971083Science Technology Innovation Foundationfor Young Teachers in BUPT under Grant No.2011RC0306+1 种基金State Major Science and Technology Special Projects under Grant No.2011ZX03005-002-02 National International Science and Technology Cooperation Project of China under Grant No.2010DFA11320
文摘Cloud computing is always adopted to enhance the computing capability of mobile systems, especially when the mobile users prefer to use some computation intensive applications. Consequently, the distributed wireless relay infrastructure should be deployed to aid the traffic transmission. To further enhance the QoS provisioning goals of wireless cooperative network, this paper puts forward a multi-objective approach for distributed optimal relay selection, which takes Bit Error Rate (BER) and Secrecy Capacity (SC) into account simultaneously. Firstly, our proposal partitions the channel state into several levels according to the received signal-to-noise ratio (SNR) and describes the time-varying Rayleigh fading channel characteristics by using first order finite-state Markov model. Secondly, we model the relay selection as Restless Multi-armed Bandit optimal solution problem with respect to the channel state and the state transition probability. Finally, simulation results demonstrate the efficiency of the proposed approach which outperforms the existing ones.
基金Special Foundation for Chongqing Science and Technology Talent(cstc2019yszx-jcyj X0006 and cstc2020yszx-jscx X0004)Advanced Research Project of Civil Aerospace Technologies in 13th Five-year Plan(D010201)。
文摘This work investigates the security issue of the energy-constrained untrusted relay network with imperfect channel reciprocity,where the relay without the built-in power supply can only scavenge energy from radio-frequency signals radiated by the source and destination.A hybrid power-splitting(PS)-and time-switching(TS)-based relaying(HPTR)protocol is presented to improve the degraded secrecy performance due to the incomplete self-interference cancellation at the destination.To evaluate the secrecy throughput(ST)of the studied system,the analytical expression of the secrecy outage probability under the delay-limited transmission mode and the closed-form lower bound of the ergodic secrecy capacity under delay-tolerant transmission mode are derived.Both linear and nonlinear models for the energy harvester at the relay are compared.The optimal PS and TS ratios are evaluated numerically.The theoretical derivations are validated by numerical results,revealing that the residual jamming has a negative effect on the secrecy performance of untrusted relay networks,which can be alleviated by the HPTR protocol.Besides,we compare the ST performance of the HPTR protocol with that of the PS and TS relaying schemes,and the results show that the HPTR protocol outperforms both PS and TS relaying protocols in terms of the ST.
基金This paper was jointly supported by the National Natural Science Foundation of China，the State Major Science and Technology Special Projects，the Science Technology Innovation Foundation for Young Teachers in BUPT
文摘Abstract：Aiming at achieving better Quality of Service （QoS） provisioning in distributed wireless cooperative networks, a novel energy efficient jammer selection approach is proposed in this pa per. We employ Secrecy Capacity （SC） to charac terize the security of transmission. In order to ac curately describe the timevarying characteristic, related channels are modeled as FiniteState M ark ov Channels （FSMCs）. The remaining energy of candidate node is considered in a similar way.
文摘With increasing the demand for transmitting secure information in wireless networks,deviceto-device(D2D)communication has great potential to improve system performance.As a well-known security risk is eavesdropping in D2D communication,ensuring information security is quite challenging.In this paper,we first obtain the closed-forms of the secrecy outage probability(SOP)and the secrecy ergodic capacity(SEC)for direct and decodeand-forward(DF)relay modes.Numerical results are presented to verify the theoretical results,and these results show the cases that the DF relay mode improves security performance compared to the direct mode at long distances between the transmitter and receiver nodes.Further,we look into the optimization problems of secure resource allocation in D2D communication to maximize the SEC and to minimize the SOP by considering the strictly positive secrecy capacity constraint as a mixed-integer non-linear programming(MINLP)problem.In the continue,we convert the MINLP to convex optimization.Finally,we solve this program with a dual method and obtain an optimal solution in the direct and DF relay modes.
