Aiming at excessive users existing in a pico base station(PBS)in the multi-layer heterogeneous networks,the resource allocation problem of maximizing the energy efficiency of the networks is investigated in this paper...Aiming at excessive users existing in a pico base station(PBS)in the multi-layer heterogeneous networks,the resource allocation problem of maximizing the energy efficiency of the networks is investigated in this paper.By deploying a relay node with energy harvesting function,the data of some users in the PBS can be transferred to an adjacent idle PBS.The bandwidth and transmitting power of users and the relay node are both considered to formulate the resource allocation optimization problem.The objective is to maximize the energy eficiency of the whole heterogeneous networks under the constraints of the user's minimum data rate and energy consumption.The suboptimal solution is obtained by using the particle swarm optimization(PSO)algorithm and quantum-behaved particle swarm optimization(QPSO)algorithm.Simulation results show that the adopted methods have higher energy efficiency than the conventional fixed power and bandwidth method.In addition,the time complexity of the adopted methods is relatively low.展开更多
Covert communication aims to prevent the warden from detecting the presence of communications,i.e.with a negligible detection probability.When the distance between the transmitter and the legitimate receiver is large,...Covert communication aims to prevent the warden from detecting the presence of communications,i.e.with a negligible detection probability.When the distance between the transmitter and the legitimate receiver is large,large transmission power is needed,which in turn increases the detection probability.Relay is an effective technique to tackle this problem,and various relaying strategies have been proposed for long-distance covert communication in these years.In this article,we first offer a tutorial on the relaying strategies utilized in covert transmission.With the emergence of reflecting intelligent surface and its application in covert communications,we propose a hybrid relay-reflecting intelligent surface(HR-RIS)-assisted strategy to further enhance the performance of covert communications,which simultaneously improves the signal strength received at the legitimate receiver and degrades that at the warden relying on optimizing both the phase and the amplitude of the HR-RIS elements.The numerical results show that the proposed HR-RIS-assisted strategy significantly outperforms the conventional RIS-aided strategy in terms of covert rate.展开更多
基金the National Natural Science Foundation of China(Nos.61871133 and 61971139)the Natural Science Foundation of Fujian Province(No.2018J01805)。
文摘Aiming at excessive users existing in a pico base station(PBS)in the multi-layer heterogeneous networks,the resource allocation problem of maximizing the energy efficiency of the networks is investigated in this paper.By deploying a relay node with energy harvesting function,the data of some users in the PBS can be transferred to an adjacent idle PBS.The bandwidth and transmitting power of users and the relay node are both considered to formulate the resource allocation optimization problem.The objective is to maximize the energy eficiency of the whole heterogeneous networks under the constraints of the user's minimum data rate and energy consumption.The suboptimal solution is obtained by using the particle swarm optimization(PSO)algorithm and quantum-behaved particle swarm optimization(QPSO)algorithm.Simulation results show that the adopted methods have higher energy efficiency than the conventional fixed power and bandwidth method.In addition,the time complexity of the adopted methods is relatively low.
基金supported in part by the National Natural Science Foundation of China(Nos.62001116,62271150,62171134,U22A2002 and 62071234)the Natural Science Foundation of Fujian Province under Grant(Nos.2020J05106 and2022J01081)+1 种基金the Major Science and Technology plan of Hainan Province under Grant ZDKJ2021022the Scientific Research Fund Project of Hainan University under Grant KYQD(ZR)-21008
文摘Covert communication aims to prevent the warden from detecting the presence of communications,i.e.with a negligible detection probability.When the distance between the transmitter and the legitimate receiver is large,large transmission power is needed,which in turn increases the detection probability.Relay is an effective technique to tackle this problem,and various relaying strategies have been proposed for long-distance covert communication in these years.In this article,we first offer a tutorial on the relaying strategies utilized in covert transmission.With the emergence of reflecting intelligent surface and its application in covert communications,we propose a hybrid relay-reflecting intelligent surface(HR-RIS)-assisted strategy to further enhance the performance of covert communications,which simultaneously improves the signal strength received at the legitimate receiver and degrades that at the warden relying on optimizing both the phase and the amplitude of the HR-RIS elements.The numerical results show that the proposed HR-RIS-assisted strategy significantly outperforms the conventional RIS-aided strategy in terms of covert rate.
