This paper studies the achievable spectral efficiency(SE)of downlink multiuser multiple-input-multiple-output(MIMO)system,where the base station(BS)is deployed an arbitrary finite antenna number and communicates simul...This paper studies the achievable spectral efficiency(SE)of downlink multiuser multiple-input-multiple-output(MIMO)system,where the base station(BS)is deployed an arbitrary finite antenna number and communicates simultaneously with many users. We assume that the BS has accurate channel state information(CSI)and adopt maximum ratio transmission(MRT)precoding. An accurate analytical result for the achievable SE is obtained. Based on the analytical result on the achievable SE,we further study the achievable energy efficiency(EE)of multiuser MIMO system by considering an energy consumption model. Results indicate that the increasing number of BS antennas can boost the achievable SE of system,whilst the achievable SE tends to a saturated rate in the high signal-tonoise ratios(SNR)regime. Furthermore,an important conclusion is that the increasing number of users is beneficial for the achievable EE and there is an optimal antenna number to maximize the EE of system.展开更多
The novel fan-shaped self-scanning photodiode array (SSPA) has the advantages of the high sensitivity with small device size and the serial video output mode. Using novel SSPA instead of the photodiode array of a semi...The novel fan-shaped self-scanning photodiode array (SSPA) has the advantages of the high sensitivity with small device size and the serial video output mode. Using novel SSPA instead of the photodiode array of a semicircular annular detectors in the laser diffraction particle size analyzer, these correctness of the results are verified by various particle samples measuring and the practical running over ten thousand hours in the desulphuration tower.展开更多
A multi-channel free space optical interconnection component, fiber optic rotary joint, was designed using a Dove prism. When the Dove prism is rotated an angle of at around the longitudinal axis, the image rotates an...A multi-channel free space optical interconnection component, fiber optic rotary joint, was designed using a Dove prism. When the Dove prism is rotated an angle of at around the longitudinal axis, the image rotates an angle of 2 at. The optical interconnection component consists of the signal transmission system, Dove prim and driving mechanism. The planetary gears are used to achieve the speed ratio of 2：l between the total optical interconnection component and the Dove prism. The Clenses are employed to couple different optical signals in the signal transmission system. The coupling loss between the receiving fiber of stationary part and the transmitting fiber of rotary part is measured.展开更多
This paper proposes a cross-layer dual adaptive coded modulation architecture using turbo codes for mobile multimedia communication, which adapts to both the varying channel characteristics and the QoS of various mult...This paper proposes a cross-layer dual adaptive coded modulation architecture using turbo codes for mobile multimedia communication, which adapts to both the varying channel characteristics and the QoS of various multimedia services simultancously to increase the average system throughput substantially. A pragmatic channeladaptive turbo coded modulation schcme, which comes within 2.5 dB of the Shannon limit, is optimally designed, and then a QoS-adaptive scheme is superimposed to build the dual adaptive architecture. Simulation results show that the novel dual adaption reduces the gap from the fading channel capacity to 2 dB when assuming different services occur in equal probability and the service duration follows exponential distribution.展开更多
An optical fiber control and transmission module is designed and realized based on Virtex-7 field programmable gata array(FPGA), which can be applied in multi-channel broadband digital receivers. The module consists o...An optical fiber control and transmission module is designed and realized based on Virtex-7 field programmable gata array(FPGA), which can be applied in multi-channel broadband digital receivers. The module consists of sampling data transfer submodule and multi-channel synchronous sampling control submodule. The sampling data transmission in 4× fiber link channel is realized with the self-defined transfer protocol. The measured maximum data rate is 4.97 Gbyte/s. By connecting coherent clocks to the transmitter and receiver endpoints and using the self-defined transfer protocol, multi-channel sampling control signals transferred in optical fibers can be received synchronously by each analog-to-digital converter(ADC) with high accuracy and strong anti-interference ability. The module designed in this paper has certain reference value in increasing the transmission bandwidth and the synchronous sampling accuracy of multi-channel broadband digital receivers.展开更多
We demonstrate a photon counting laser ranging experiment with a four-channel single-photon detector(SPD). The multi-channel SPD improve the counting rate more than 4×10~7 cps, which makes possible for the distan...We demonstrate a photon counting laser ranging experiment with a four-channel single-photon detector(SPD). The multi-channel SPD improve the counting rate more than 4×10~7 cps, which makes possible for the distance measurement performed even in daylight. However, the time-correlated single-photon counting(TCSPC) technique cannot distill the signal easily while the fast moving targets are submersed in the strong background. We propose a dynamic TCSPC method for fast moving targets measurement by varying coincidence window in real time. In the experiment, we prove that targets with velocity of 5 km/s can be detected according to the method, while the echo rate is 20% with the background counts of more than 1.2×10~7 cps.展开更多
基金supported by the National Natural Science Foundation of China under Grants 61531011 and 61450110445the International Science and Technology Cooperation Program of China under Grant 2014DFT10300 and China Scholarship Council
文摘This paper studies the achievable spectral efficiency(SE)of downlink multiuser multiple-input-multiple-output(MIMO)system,where the base station(BS)is deployed an arbitrary finite antenna number and communicates simultaneously with many users. We assume that the BS has accurate channel state information(CSI)and adopt maximum ratio transmission(MRT)precoding. An accurate analytical result for the achievable SE is obtained. Based on the analytical result on the achievable SE,we further study the achievable energy efficiency(EE)of multiuser MIMO system by considering an energy consumption model. Results indicate that the increasing number of BS antennas can boost the achievable SE of system,whilst the achievable SE tends to a saturated rate in the high signal-tonoise ratios(SNR)regime. Furthermore,an important conclusion is that the increasing number of users is beneficial for the achievable EE and there is an optimal antenna number to maximize the EE of system.
文摘The novel fan-shaped self-scanning photodiode array (SSPA) has the advantages of the high sensitivity with small device size and the serial video output mode. Using novel SSPA instead of the photodiode array of a semicircular annular detectors in the laser diffraction particle size analyzer, these correctness of the results are verified by various particle samples measuring and the practical running over ten thousand hours in the desulphuration tower.
基金the National Natural Science Foundation of China (No. 60577013)program for New Century Talents in University,Ministry of Education of China
文摘A multi-channel free space optical interconnection component, fiber optic rotary joint, was designed using a Dove prism. When the Dove prism is rotated an angle of at around the longitudinal axis, the image rotates an angle of 2 at. The optical interconnection component consists of the signal transmission system, Dove prim and driving mechanism. The planetary gears are used to achieve the speed ratio of 2：l between the total optical interconnection component and the Dove prism. The Clenses are employed to couple different optical signals in the signal transmission system. The coupling loss between the receiving fiber of stationary part and the transmitting fiber of rotary part is measured.
基金This work is supported by the High Technology Research and Development Program of China(No. 2001AA121031)the National Natural Science Foundation of China (No. 60072028)
文摘This paper proposes a cross-layer dual adaptive coded modulation architecture using turbo codes for mobile multimedia communication, which adapts to both the varying channel characteristics and the QoS of various multimedia services simultancously to increase the average system throughput substantially. A pragmatic channeladaptive turbo coded modulation schcme, which comes within 2.5 dB of the Shannon limit, is optimally designed, and then a QoS-adaptive scheme is superimposed to build the dual adaptive architecture. Simulation results show that the novel dual adaption reduces the gap from the fading channel capacity to 2 dB when assuming different services occur in equal probability and the service duration follows exponential distribution.
文摘An optical fiber control and transmission module is designed and realized based on Virtex-7 field programmable gata array(FPGA), which can be applied in multi-channel broadband digital receivers. The module consists of sampling data transfer submodule and multi-channel synchronous sampling control submodule. The sampling data transmission in 4× fiber link channel is realized with the self-defined transfer protocol. The measured maximum data rate is 4.97 Gbyte/s. By connecting coherent clocks to the transmitter and receiver endpoints and using the self-defined transfer protocol, multi-channel sampling control signals transferred in optical fibers can be received synchronously by each analog-to-digital converter(ADC) with high accuracy and strong anti-interference ability. The module designed in this paper has certain reference value in increasing the transmission bandwidth and the synchronous sampling accuracy of multi-channel broadband digital receivers.
基金supported by the National Natural Science Foundation of China(No.11374105)
文摘We demonstrate a photon counting laser ranging experiment with a four-channel single-photon detector(SPD). The multi-channel SPD improve the counting rate more than 4×10~7 cps, which makes possible for the distance measurement performed even in daylight. However, the time-correlated single-photon counting(TCSPC) technique cannot distill the signal easily while the fast moving targets are submersed in the strong background. We propose a dynamic TCSPC method for fast moving targets measurement by varying coincidence window in real time. In the experiment, we prove that targets with velocity of 5 km/s can be detected according to the method, while the echo rate is 20% with the background counts of more than 1.2×10~7 cps.
