Discrete-rate adaptive modulation （AM） scheme for distributed antenna system （DAS） with imperfect channel state information （CSI） is developed, and the corresponding performance is investigated in composite Rayl...Discrete-rate adaptive modulation （AM） scheme for distributed antenna system （DAS） with imperfect channel state information （CSI） is developed, and the corresponding performance is investigated in composite Rayleigh channel. Subject to target bit error rate （BER） constraint, an improved fixed switching threshold （FST） for the AM scheme is presented by means of tightly-approximate BER expression, and it can avoid the performance loss fxom conventional FST. Based on the imperfect CSI, the variable switching threshold （VST） is derived by utilizing the maximum a posteriori method. This VST includes the improved FST as a special case, and may lower the impact of estimation error on the performance. By the switching thresholds, the spectrum efficiency （SE） and average BER of the system are respectively derived, and resulting closed- form expressions are attained. With these expressions, the system performance can be effectively evaluated. Simulation results show that the derived theoretical SE and BER can match the simulations well. Moreover, the AM with the presented FST has higher SE than that with the conventional one, and the AM with VST can tolerate the large estimation error while maintaining the target BER.展开更多
This paper proposes a communication system for nanosatellite Earth observa-tion preliminary design technique as useful tools for managing and improving various aspects of regional and national resources. Under analysi...This paper proposes a communication system for nanosatellite Earth observa-tion preliminary design technique as useful tools for managing and improving various aspects of regional and national resources. Under analysis was pro-posed a design process for the low Earth orbit nanosatellite communication system. In proposed paper have been formulated and solved next goals: re-viewed Earth observation systems and studied their design parameters, ana-lyzed the on-board antennas design background and provided analytical esti-mations, such as design a passband quadrature phase shift keying transmitter and receiver in Simulink, was obtained a bit error rate curves by using a Sim-ulink/MathWorks, generated an offset quadrature phase shift keying waveform and investigated their characteristics, observed and analyzed the diagrams, constellation, and the signal trajectories of quadrature phase shift keying ac-cording contemporary design concept. As a result, this allows to propose in-novative communication system design techniques applied for the nanosatel-lite category.展开更多
Massive multiple input and multiple output(MIMO) is a key technology of the fifth generation(5 G) wireless communication systems, which brings various advantages, such as high spectral efficiency and energy efficiency...Massive multiple input and multiple output(MIMO) is a key technology of the fifth generation(5 G) wireless communication systems, which brings various advantages, such as high spectral efficiency and energy efficiency. In MIMO system, spatial modulation(SM) has recently emerged as a new transmission method. In this paper, in order to improve the security in SM-MIMO, a physical layer encryption approach named chaotic antenna-index three-dimensional modulation and constellation points rotated(CATMCPR) encryption scheme is proposed, which utilizes the chaotic theory and spatial modulation techniques. The conventional physical-layer encryption in SM-MIMO suffers from spectral efficiency(SE) performance degradation and usually needs a preshared key, prior channel state information(CSI) or excess jamming power. By contrast, we show that the CATMCPR scheme can not only achieve securely communication but also improve above drawbacks. We evaluate the performances of the proposed scheme by an analysis and computer simulations.展开更多
This paper investigates secure transmission in a wireless powered communication network(WPCN)with an energy harvesting(EH)source configured with multiple antennas.In the WPCN,the EH source harvests energy from the rad...This paper investigates secure transmission in a wireless powered communication network(WPCN)with an energy harvesting(EH)source configured with multiple antennas.In the WPCN,the EH source harvests energy from the radio frequency(RF)signals broadcasted by a power beacon(PB),and purely relies on the harvested energy to communicate with the destination in the presence of passive eavesdroppers.It is noteworthy that the RF-EH source is equipped with a finite energy storage to accumulate the harvested energy for the future usage.Moreover,due to energy-constraint and complexitylimitation,the multi-antenna source is only configured with a single RF-chain.To enhance the security for the WPCN,we propose two adaptive transmission schemes,i.e.,energy-aware transmit antenna selection(EATAS)and energy-aware differential spatial modulation(EADSM).According to the energy status and the channel quality,the source adaptively decides whether to transmit confidential information or harvest RF energy.To evaluate the secrecy performance of the proposed schemes,we first study the evolution of the energy storage,and then derive the analytical expressions of connection outage probability(COP),secrecy outage probability(SOP)and efficient secrecy throughput(EST).Numerical results demonstrate that our proposed schemes outperform the existing schemes,i.e.,time-switching based TAS(TS-TAS)Received:May 19,2020 Revised:Sep.13,2020 Editor:Deli Qiao and accumulate-then-transmit(ATT).And,increasing the transmit power of the PB or the capacity of the source’s energy storage is helpful to improve the secrecy performance.Moreover,there exists an optimal transmission rate for each proposed scheme to achieve best secrecy performance.展开更多
Abstract A novel approach for the synthesis of shaped beam patterns in time-modulated antenna arrays(TMAAs)with static uniform amplitude and phase excitations is proposed in this paper.Based on the sideband radiation ...Abstract A novel approach for the synthesis of shaped beam patterns in time-modulated antenna arrays(TMAAs)with static uniform amplitude and phase excitations is proposed in this paper.Based on the sideband radiation in TMAAs,shaped beam patterns can be realized by only controlling the switch-on time sequences of the TMAAs.Differential evolution(DE)algorithm is adopted to optimize the time modulation parameters to obtain the desired flat-top and cosecant-squared beams and to suppress the sidelobe levels(SLLs).Simulation results of a time-modulated linear array(TMLA)and a timemodulated semicircular array(TMSA)demonstrate the effectiveness of the proposed approach for the synthesis of shaped beam patterns from TMAAs.展开更多
基金National Natural Science Foundation of China，Open Research Fund of National Mobile Communications Research Laboratory of Southeast University，Qing Lan Project of Jiangsu Province,the Fundamental Research Funds for the Central Universities,Research Founding of Graduate Innovation Center in NUAA，Innovation Fund of College of Electronic and Information Engineering of NUAA
文摘Discrete-rate adaptive modulation （AM） scheme for distributed antenna system （DAS） with imperfect channel state information （CSI） is developed, and the corresponding performance is investigated in composite Rayleigh channel. Subject to target bit error rate （BER） constraint, an improved fixed switching threshold （FST） for the AM scheme is presented by means of tightly-approximate BER expression, and it can avoid the performance loss fxom conventional FST. Based on the imperfect CSI, the variable switching threshold （VST） is derived by utilizing the maximum a posteriori method. This VST includes the improved FST as a special case, and may lower the impact of estimation error on the performance. By the switching thresholds, the spectrum efficiency （SE） and average BER of the system are respectively derived, and resulting closed- form expressions are attained. With these expressions, the system performance can be effectively evaluated. Simulation results show that the derived theoretical SE and BER can match the simulations well. Moreover, the AM with the presented FST has higher SE than that with the conventional one, and the AM with VST can tolerate the large estimation error while maintaining the target BER.
文摘This paper proposes a communication system for nanosatellite Earth observa-tion preliminary design technique as useful tools for managing and improving various aspects of regional and national resources. Under analysis was pro-posed a design process for the low Earth orbit nanosatellite communication system. In proposed paper have been formulated and solved next goals: re-viewed Earth observation systems and studied their design parameters, ana-lyzed the on-board antennas design background and provided analytical esti-mations, such as design a passband quadrature phase shift keying transmitter and receiver in Simulink, was obtained a bit error rate curves by using a Sim-ulink/MathWorks, generated an offset quadrature phase shift keying waveform and investigated their characteristics, observed and analyzed the diagrams, constellation, and the signal trajectories of quadrature phase shift keying ac-cording contemporary design concept. As a result, this allows to propose in-novative communication system design techniques applied for the nanosatel-lite category.
基金supported in part by the National Natural Science Foundation of China under Grant 61502518,61372098 and 61702536
文摘Massive multiple input and multiple output(MIMO) is a key technology of the fifth generation(5 G) wireless communication systems, which brings various advantages, such as high spectral efficiency and energy efficiency. In MIMO system, spatial modulation(SM) has recently emerged as a new transmission method. In this paper, in order to improve the security in SM-MIMO, a physical layer encryption approach named chaotic antenna-index three-dimensional modulation and constellation points rotated(CATMCPR) encryption scheme is proposed, which utilizes the chaotic theory and spatial modulation techniques. The conventional physical-layer encryption in SM-MIMO suffers from spectral efficiency(SE) performance degradation and usually needs a preshared key, prior channel state information(CSI) or excess jamming power. By contrast, we show that the CATMCPR scheme can not only achieve securely communication but also improve above drawbacks. We evaluate the performances of the proposed scheme by an analysis and computer simulations.
基金supported in part by the National Science Foundations of China under Grant 61801496 and 61801497the Defense Science Foundations of China under Grant 2019-JCJQ-JJ-221the National University of Defense Technology Youth Innovation Award Research Project under Grant 23200306。
文摘This paper investigates secure transmission in a wireless powered communication network(WPCN)with an energy harvesting(EH)source configured with multiple antennas.In the WPCN,the EH source harvests energy from the radio frequency(RF)signals broadcasted by a power beacon(PB),and purely relies on the harvested energy to communicate with the destination in the presence of passive eavesdroppers.It is noteworthy that the RF-EH source is equipped with a finite energy storage to accumulate the harvested energy for the future usage.Moreover,due to energy-constraint and complexitylimitation,the multi-antenna source is only configured with a single RF-chain.To enhance the security for the WPCN,we propose two adaptive transmission schemes,i.e.,energy-aware transmit antenna selection(EATAS)and energy-aware differential spatial modulation(EADSM).According to the energy status and the channel quality,the source adaptively decides whether to transmit confidential information or harvest RF energy.To evaluate the secrecy performance of the proposed schemes,we first study the evolution of the energy storage,and then derive the analytical expressions of connection outage probability(COP),secrecy outage probability(SOP)and efficient secrecy throughput(EST).Numerical results demonstrate that our proposed schemes outperform the existing schemes,i.e.,time-switching based TAS(TS-TAS)Received:May 19,2020 Revised:Sep.13,2020 Editor:Deli Qiao and accumulate-then-transmit(ATT).And,increasing the transmit power of the PB or the capacity of the source’s energy storage is helpful to improve the secrecy performance.Moreover,there exists an optimal transmission rate for each proposed scheme to achieve best secrecy performance.
基金This work was supported in part by the National Natural Science Foundation of China(Grant No.60971030)the Program for New Century Excellent Talent in University(No.NCET-06-0809)the 111 project of China(No.B07046).
文摘Abstract A novel approach for the synthesis of shaped beam patterns in time-modulated antenna arrays(TMAAs)with static uniform amplitude and phase excitations is proposed in this paper.Based on the sideband radiation in TMAAs,shaped beam patterns can be realized by only controlling the switch-on time sequences of the TMAAs.Differential evolution(DE)algorithm is adopted to optimize the time modulation parameters to obtain the desired flat-top and cosecant-squared beams and to suppress the sidelobe levels(SLLs).Simulation results of a time-modulated linear array(TMLA)and a timemodulated semicircular array(TMSA)demonstrate the effectiveness of the proposed approach for the synthesis of shaped beam patterns from TMAAs.
