As a novel signaling technology,the power splitting receiver(PSR)simultaneously employs both the coherent and non-coherent signal processing.In order to improve its communication performance,an intelligent reflecting ...As a novel signaling technology,the power splitting receiver(PSR)simultaneously employs both the coherent and non-coherent signal processing.In order to improve its communication performance,an intelligent reflecting surface(IRS)is introduced into its signal propagation path.Consequently,an IRSaided PSR is concerned for a point-to-point(P2P)data link,where both the single-antenna and multiantenna deployments on the receiver are discussed.We aim at maximizing the capacity of the concerned P2P data-link by jointly optimizing the passive beamforming of IRS and the splitting ratio of PSR,either in single-antenna or multi-antenna case.However,owing to the coupling of multiple variables,the optimization problems are non-convex and challenging,especially in the later multi-antenna case.The proposed alternating-approximating algorithm(A-A),aided by semi-definite relaxation(SDR)and successive convex approximation(SCA)methods,etc.,successfully overcomes these challenges.We compare the IRS-aided PSR system that optimized by our proposed algorithm to the systems without IRS or PSR,and the systems without joint optimization.The simulation results show that our proposal has a better performance.展开更多
A two-dimensional rectangular solenoid transmitting coil is proposed to address the problem that the three-dimensional receiving coil occupies excessive space inside the capsule robot.The transmitting coil consists of...A two-dimensional rectangular solenoid transmitting coil is proposed to address the problem that the three-dimensional receiving coil occupies excessive space inside the capsule robot.The transmitting coil consists of two pairs of rectangular solenoid coils distributed radially along the human body.By changing the direction of current flow,it can generate a two-dimensional magnetic field covering the whole central plane.Firstly,the working mechanism of the wireless power transfer system is introduced,and then the spatial electromagnetic field generated by the transmitting coil is analyzed through both mathematical calculations and finite element simulations.Finally,an experimental platform is built to determine the optimal resonant frequency of the system and validate its feasibility based on the power transfer efficiency and the receiving power.The experimental results demonstrate that when the receiving coil is located at the center of the coil pair,the receiving power is 1416 mW and the power transfer efficiency is 3.96%.Additionally,when the receiving coil operates in the central plane,it can receive sufficient energy regardless of the orientation.展开更多
As different power has its own receivers,this paper analyzes and designs a multiple-receiver wireless power transfer(WPT)system systematically.The equivalent circuit model of the system is established to analyze the k...As different power has its own receivers,this paper analyzes and designs a multiple-receiver wireless power transfer(WPT)system systematically.The equivalent circuit model of the system is established to analyze the key parameters including transmitter power,receiver power,transmission efficiency,and each receiver power allocation.A control circuit is proposed to achieve the maximum transmission efficiency and transmitter power control and arbitrary receiver power allocation ratios for different receivers.Through the proposed control circuit,receivers with different loads can allocate appropriate power according to its power demand,the transmitter power and system efficiency do not vary with the change of the number of receivers.Finally,this control circuit is validated using a 130-kHz WPT system with three receivers whose power received is 3:10:12,and the overall system efficiency can reach as high as 55.5%.展开更多
The paper proposes a low power non-volatile baseband processor with wake-up identification(WUI) receiver for LR-WPAN transceiver.It consists of WUI receiver,main receiver,transmitter,non-volatile memory(NVM) and power...The paper proposes a low power non-volatile baseband processor with wake-up identification(WUI) receiver for LR-WPAN transceiver.It consists of WUI receiver,main receiver,transmitter,non-volatile memory(NVM) and power management module.The main receiver adopts a unified simplified synchronization method and channel codec with proactive Reed-Solomon Bypass technique,which increases the robustness and energy efficiency of receiver.The WUI receiver specifies the communication node and wakes up the transceiver to reduce average power consumption of the transceiver.The embedded NVM can backup/restore the states information of processor that avoids the loss of the state information caused by power failure and reduces the unnecessary power of repetitive computation when the processor is waked up from power down mode.The baseband processor is designed and verified on a FPGA board.The simulated power consumption of processor is 5.1uW for transmitting and 28.2μW for receiving.The WUI receiver technique reduces the average power consumption of transceiver remarkably.If the transceiver operates 30 seconds in every 15 minutes,the average power consumption of the transceiver can be reduced by two orders of magnitude.The NVM avoids the loss of the state information caused by power failure and energy waste caused by repetitive computation.展开更多
Capacitive micromachined ultrasonic transducer(CMUT)technology is a potential candidate to implement an ultrasonic power receiver for implantable medical devices(IMDs)because CMUT technology employs photolithography-b...Capacitive micromachined ultrasonic transducer(CMUT)technology is a potential candidate to implement an ultrasonic power receiver for implantable medical devices(IMDs)because CMUT technology employs photolithography-based microfabrication techniques amenable to miniaturization,integration with electronics,and biocompatibility.Pre-charged CMUTs operating in constant-charge mode eliminate the DC bias and this mode of operation is more suitable for ultrasound power transfer to IMDs.We designed and fabricated a novel pre-charged CMUT structure with a built-in charge storage capacitor.This new configuration features a floating electrode between the upper and lower electrodes.Charges are stored on this floating electrode prior to implantation by directly bringing the floating electrode into contact with the bottom electrode while applying a DC bias between the top and bottom electrodes of the CMUT.After pre-charging the CMUT,the charges are retained without any leakage,as confirmed by occasional measurements over the course of about two years.We have also demonstrated that this device allows operation without a DC bias and can be used as a power receiver in an IMD.In the presented design,the CMUT can be pre-charged at a desired precise charge level.The amount of trapped charge can be controlled by holding the floating electrode in contact with the bottom electrode by applying external ultrasound pressure and simultaneously maintaining a DC bias.The maximum received power was 10.1 mW,corresponding to a received power density of 3.1 mW/mm2,with a 14.5%efficiency.We have achieved an acoustic-toelectrical power conversion efficiency as high as 29.7%at lower input power levels.展开更多
Visible light communication(VLC),which is a prominent emerging solution that complements the radio frequency(RF)technology,exhibits the potential to meet the demands of fifth-generation(5G)and beyond technologies.The ...Visible light communication(VLC),which is a prominent emerging solution that complements the radio frequency(RF)technology,exhibits the potential to meet the demands of fifth-generation(5G)and beyond technologies.The random movement of mobile terminals in the indoor environment is a challenge in the VLC system.The model of optical attocells has a critical role in the uniform distribution and the quality of communication links in terms of received power and signal-to-noise ratio(SNR).As such,the optical attocells positions were optimized in this study with a developed try and error(TE)algorithm.The optimized optical attocells were examined and compared with previous models.This novel approach had successfully increased minimum received power from−1.29 to−0.225 dBm,along with enhanced SNR performance by 2.06 dB.The bit error rate(BER)was reduced to 4.42×10−8 and 6.63×10−14 by utilizing OOK-NRZ and BPSK modulation techniques,respectively.The optimized attocells positions displayed better uniform distribution,as both received power and SNR performances improved by 0.45 and 0.026,respectively.As the results of the proposed model are optimal,it is suitable for standard office and room model applications.展开更多
The blue-green light in the 450 nm to 550 nm band is usually used in underwater wireless optical communication (UWOC). The blue-green light transmission in seawater is scattered by the seawater effect and can achieve ...The blue-green light in the 450 nm to 550 nm band is usually used in underwater wireless optical communication (UWOC). The blue-green light transmission in seawater is scattered by the seawater effect and can achieve communication in non-line-of-sight (NLOS) transmission mode. Compared to line-of-sight (LOS) transmission, NLOS transmission does not require alignment and can be adapted to various underwater environments. The scattering coefficients of seawater at different depths are different, which makes the scattering of light in different depths of seawater different. In this paper, the received optical power and bit error rate (BER) of the photodetector (PD) were calculated when the scattering coefficients of blue-green light in seawater vary from large to small with increasing depth for NLOS transmission. The results show that blue-green light in different depths of seawater in the same way NLOS communication at the same distance, the received optical power and BER at the receiver are different, and the received optical power of green light is greater than that of blue light. Increasing the forward scattering coverage of the laser will suppress the received optical power of the PD, so when performing NLOS communication, appropriate trade-offs should be made between the forward scattering coverage of the laser and the received optical power.展开更多
Uplink non-orthogonM multiple access （NOMA） is a promising technique to meet the requirements of the fifth generation （5G） and beyond systems. Various NOMA schemes have been proposed in both academia and industry....Uplink non-orthogonM multiple access （NOMA） is a promising technique to meet the requirements of the fifth generation （5G） and beyond systems. Various NOMA schemes have been proposed in both academia and industry. However, most existing schemes assume equal average received power, which limits the performance. We propose three enhancements of uplink NOMA to achieve the requirements of massive connectivity and high reliability in 5G, where unequal average received power is exploited as part of the multiple access signature. First, the optimal sequences targeting to generalized Welch-bound equality （GWBE） are obtained for unequal average received power. Then user grouping with multi-level received powers is proposed for better successive interference cancellation （SIC） at the receiver. Finally, sequence grouping based on the cross-correlation properties of sequences is proposed to reduce inter-and intra-group interference. Simulation results show that by incorporating multi-level received powers and sequence grouping into existing NOMA schemes, for an NOMA system with 400% overloading and fixed signature allocation, 3 dB and 10 dB signal-to-noise ratio （SNR） gains at 0.1 block error rate （BLER） target can be achieved compared with existing NOMA schemes and orthogonal multiple access （OMA）, respectively. Besides, 0.01 BLER target can be achieved while an error floor exists in existing NOMA schemes. Under random sequence selection, collision probability is reduced by multi-level powers. In addition, GWBE sequences achieve lower BLER than existing sequences and the gain is large especially for low BLER requirements. This shows that the proposed scheme can support larger connectivity and higher reliability.展开更多
Free space optical （FSO） communication has been considered as an alternative to radio relay link line-of- sight （LOS） communication systems. The total attenuation is a combination of atmospheric attenuation in the...Free space optical （FSO） communication has been considered as an alternative to radio relay link line-of- sight （LOS） communication systems. The total attenuation is a combination of atmospheric attenuation in the atmosphere and geometric losses. The purpose of this paper is to study the geometric loss versus link range （in kin）, divergence angle, transmitter aperture diameter, and receiver aperture diameter. Total attenuation versus low visibility, average visibility, beam divergence, link range and rainfall rate were presented in this paper. Atmospheric attenuation （in dB） and scattering coefficient （in km-~） for several Yemeni main cities were explored. The study was concentrated on received power versus low and average visibilities and link range. Series of related simulation results were illustrated and discussed in this paper about the climate effects on performance of FSO communication systems in Yemen.展开更多
基金supported by National Key R&D Program of China with Grant number 2019YFB1803400in part by Sichuan Science and Technology Program under Grant 2024NSFSC0472。
文摘As a novel signaling technology,the power splitting receiver(PSR)simultaneously employs both the coherent and non-coherent signal processing.In order to improve its communication performance,an intelligent reflecting surface(IRS)is introduced into its signal propagation path.Consequently,an IRSaided PSR is concerned for a point-to-point(P2P)data link,where both the single-antenna and multiantenna deployments on the receiver are discussed.We aim at maximizing the capacity of the concerned P2P data-link by jointly optimizing the passive beamforming of IRS and the splitting ratio of PSR,either in single-antenna or multi-antenna case.However,owing to the coupling of multiple variables,the optimization problems are non-convex and challenging,especially in the later multi-antenna case.The proposed alternating-approximating algorithm(A-A),aided by semi-definite relaxation(SDR)and successive convex approximation(SCA)methods,etc.,successfully overcomes these challenges.We compare the IRS-aided PSR system that optimized by our proposed algorithm to the systems without IRS or PSR,and the systems without joint optimization.The simulation results show that our proposal has a better performance.
基金the National Natural Science Foundation of China(Nos.62273225,81971767,62103267 and 62103263)。
文摘A two-dimensional rectangular solenoid transmitting coil is proposed to address the problem that the three-dimensional receiving coil occupies excessive space inside the capsule robot.The transmitting coil consists of two pairs of rectangular solenoid coils distributed radially along the human body.By changing the direction of current flow,it can generate a two-dimensional magnetic field covering the whole central plane.Firstly,the working mechanism of the wireless power transfer system is introduced,and then the spatial electromagnetic field generated by the transmitting coil is analyzed through both mathematical calculations and finite element simulations.Finally,an experimental platform is built to determine the optimal resonant frequency of the system and validate its feasibility based on the power transfer efficiency and the receiving power.The experimental results demonstrate that when the receiving coil is located at the center of the coil pair,the receiving power is 1416 mW and the power transfer efficiency is 3.96%.Additionally,when the receiving coil operates in the central plane,it can receive sufficient energy regardless of the orientation.
基金supported by the National Natural Science Foundation of China under Grant No.51574198Nanchong City 2018 Special Fund for City-School Cooperation under Grant No.18SXHZ0021
文摘As different power has its own receivers,this paper analyzes and designs a multiple-receiver wireless power transfer(WPT)system systematically.The equivalent circuit model of the system is established to analyze the key parameters including transmitter power,receiver power,transmission efficiency,and each receiver power allocation.A control circuit is proposed to achieve the maximum transmission efficiency and transmitter power control and arbitrary receiver power allocation ratios for different receivers.Through the proposed control circuit,receivers with different loads can allocate appropriate power according to its power demand,the transmitter power and system efficiency do not vary with the change of the number of receivers.Finally,this control circuit is validated using a 130-kHz WPT system with three receivers whose power received is 3:10:12,and the overall system efficiency can reach as high as 55.5%.
基金supported in part by the National Natural Science Foundation of China(No.61306027)
文摘The paper proposes a low power non-volatile baseband processor with wake-up identification(WUI) receiver for LR-WPAN transceiver.It consists of WUI receiver,main receiver,transmitter,non-volatile memory(NVM) and power management module.The main receiver adopts a unified simplified synchronization method and channel codec with proactive Reed-Solomon Bypass technique,which increases the robustness and energy efficiency of receiver.The WUI receiver specifies the communication node and wakes up the transceiver to reduce average power consumption of the transceiver.The embedded NVM can backup/restore the states information of processor that avoids the loss of the state information caused by power failure and reduces the unnecessary power of repetitive computation when the processor is waked up from power down mode.The baseband processor is designed and verified on a FPGA board.The simulated power consumption of processor is 5.1uW for transmitting and 28.2μW for receiving.The WUI receiver technique reduces the average power consumption of transceiver remarkably.If the transceiver operates 30 seconds in every 15 minutes,the average power consumption of the transceiver can be reduced by two orders of magnitude.The NVM avoids the loss of the state information caused by power failure and energy waste caused by repetitive computation.
基金supported by the NSF under Grant 1160483 as part of a Centreto-Center collaborative partnership with NUI Galway,Ireland and Queen’s University,Belfast,Northern Irelandperformed in part at the NCSU Nanofabrication Facility(NNF),and Duke University Shared Materials Instrumentation Facility(SMIF),all of which are members of the North Carolina Research Triangle Nanotechnology Network(RTNN)which is supported by the National Science Foundation(Grant ECCS-2025064)as part of the National Nanotechnology Coordinated Infrastructure(NNCI).
文摘Capacitive micromachined ultrasonic transducer(CMUT)technology is a potential candidate to implement an ultrasonic power receiver for implantable medical devices(IMDs)because CMUT technology employs photolithography-based microfabrication techniques amenable to miniaturization,integration with electronics,and biocompatibility.Pre-charged CMUTs operating in constant-charge mode eliminate the DC bias and this mode of operation is more suitable for ultrasound power transfer to IMDs.We designed and fabricated a novel pre-charged CMUT structure with a built-in charge storage capacitor.This new configuration features a floating electrode between the upper and lower electrodes.Charges are stored on this floating electrode prior to implantation by directly bringing the floating electrode into contact with the bottom electrode while applying a DC bias between the top and bottom electrodes of the CMUT.After pre-charging the CMUT,the charges are retained without any leakage,as confirmed by occasional measurements over the course of about two years.We have also demonstrated that this device allows operation without a DC bias and can be used as a power receiver in an IMD.In the presented design,the CMUT can be pre-charged at a desired precise charge level.The amount of trapped charge can be controlled by holding the floating electrode in contact with the bottom electrode by applying external ultrasound pressure and simultaneously maintaining a DC bias.The maximum received power was 10.1 mW,corresponding to a received power density of 3.1 mW/mm2,with a 14.5%efficiency.We have achieved an acoustic-toelectrical power conversion efficiency as high as 29.7%at lower input power levels.
基金the grant names“ProfessionalDevelopment Research University Grant”(“UTM Vot No.05E69”and“TDR grant Vot No.05G27”).
文摘Visible light communication(VLC),which is a prominent emerging solution that complements the radio frequency(RF)technology,exhibits the potential to meet the demands of fifth-generation(5G)and beyond technologies.The random movement of mobile terminals in the indoor environment is a challenge in the VLC system.The model of optical attocells has a critical role in the uniform distribution and the quality of communication links in terms of received power and signal-to-noise ratio(SNR).As such,the optical attocells positions were optimized in this study with a developed try and error(TE)algorithm.The optimized optical attocells were examined and compared with previous models.This novel approach had successfully increased minimum received power from−1.29 to−0.225 dBm,along with enhanced SNR performance by 2.06 dB.The bit error rate(BER)was reduced to 4.42×10−8 and 6.63×10−14 by utilizing OOK-NRZ and BPSK modulation techniques,respectively.The optimized attocells positions displayed better uniform distribution,as both received power and SNR performances improved by 0.45 and 0.026,respectively.As the results of the proposed model are optimal,it is suitable for standard office and room model applications.
文摘The blue-green light in the 450 nm to 550 nm band is usually used in underwater wireless optical communication (UWOC). The blue-green light transmission in seawater is scattered by the seawater effect and can achieve communication in non-line-of-sight (NLOS) transmission mode. Compared to line-of-sight (LOS) transmission, NLOS transmission does not require alignment and can be adapted to various underwater environments. The scattering coefficients of seawater at different depths are different, which makes the scattering of light in different depths of seawater different. In this paper, the received optical power and bit error rate (BER) of the photodetector (PD) were calculated when the scattering coefficients of blue-green light in seawater vary from large to small with increasing depth for NLOS transmission. The results show that blue-green light in different depths of seawater in the same way NLOS communication at the same distance, the received optical power and BER at the receiver are different, and the received optical power of green light is greater than that of blue light. Increasing the forward scattering coverage of the laser will suppress the received optical power of the PD, so when performing NLOS communication, appropriate trade-offs should be made between the forward scattering coverage of the laser and the received optical power.
文摘Uplink non-orthogonM multiple access （NOMA） is a promising technique to meet the requirements of the fifth generation （5G） and beyond systems. Various NOMA schemes have been proposed in both academia and industry. However, most existing schemes assume equal average received power, which limits the performance. We propose three enhancements of uplink NOMA to achieve the requirements of massive connectivity and high reliability in 5G, where unequal average received power is exploited as part of the multiple access signature. First, the optimal sequences targeting to generalized Welch-bound equality （GWBE） are obtained for unequal average received power. Then user grouping with multi-level received powers is proposed for better successive interference cancellation （SIC） at the receiver. Finally, sequence grouping based on the cross-correlation properties of sequences is proposed to reduce inter-and intra-group interference. Simulation results show that by incorporating multi-level received powers and sequence grouping into existing NOMA schemes, for an NOMA system with 400% overloading and fixed signature allocation, 3 dB and 10 dB signal-to-noise ratio （SNR） gains at 0.1 block error rate （BLER） target can be achieved compared with existing NOMA schemes and orthogonal multiple access （OMA）, respectively. Besides, 0.01 BLER target can be achieved while an error floor exists in existing NOMA schemes. Under random sequence selection, collision probability is reduced by multi-level powers. In addition, GWBE sequences achieve lower BLER than existing sequences and the gain is large especially for low BLER requirements. This shows that the proposed scheme can support larger connectivity and higher reliability.
文摘Free space optical （FSO） communication has been considered as an alternative to radio relay link line-of- sight （LOS） communication systems. The total attenuation is a combination of atmospheric attenuation in the atmosphere and geometric losses. The purpose of this paper is to study the geometric loss versus link range （in kin）, divergence angle, transmitter aperture diameter, and receiver aperture diameter. Total attenuation versus low visibility, average visibility, beam divergence, link range and rainfall rate were presented in this paper. Atmospheric attenuation （in dB） and scattering coefficient （in km-~） for several Yemeni main cities were explored. The study was concentrated on received power versus low and average visibilities and link range. Series of related simulation results were illustrated and discussed in this paper about the climate effects on performance of FSO communication systems in Yemen.
