The interleaving/multiplexing technique was used to realize a 200?MHz real time data acquisition system. Two 100?MHz ADC modules worked parallelly and every ADC plays out data in ping pang fashion. The design improv...The interleaving/multiplexing technique was used to realize a 200?MHz real time data acquisition system. Two 100?MHz ADC modules worked parallelly and every ADC plays out data in ping pang fashion. The design improved the system conversion rata to 200?MHz and reduced the speed of data transporting and storing to 50?MHz. The high speed HDPLD and ECL logic parts were used to control system timing and the memory address. The multi layer print board and the shield were used to decrease interference produced by the high speed circuit. The system timing was designed carefully. The interleaving/multiplexing technique could improve the system conversion rata greatly while reducing the speed of external digital interfaces greatly. The design resolved the difficulties in high speed system effectively. The experiment proved the data acquisition system is stable and accurate.展开更多
A novel interleaving based selected mapping (SLM) scheme to depress the relatively high peak power of transmit signals in multicarrier communications is proposed. In the scheme, a group of bit-level interleavers spa...A novel interleaving based selected mapping (SLM) scheme to depress the relatively high peak power of transmit signals in multicarrier communications is proposed. In the scheme, a group of bit-level interleavers spanning only a few bits are used to produce multiple sequences representing the same information, and one of the sequences resulting in the lowest peak-to-average power ratio (PAPR) is selected for transmission. The implementation of the scheme including the structure of the short-span interleaver is illustrated. The performance of this PAPR reduction scheme is investigated by simulations. This scheme exhibits a good PAPR reduction performance, and for signals of high level modulation, such as 16QAM and 64QAM, it approaches the best performance of all SLM schemes. Compared to the conventional interleaving SLM, this short-span interleaving SLM results in a very short time delay, requires very few register units for buffering, and can be easily implemented by hardware.展开更多
The problem of scheduling radar dwells in multifunction phased array radar systems is addressed. A novel dwell scheduling algorithm is proposed. The whole scheduling process is based on an online pulse interleaving te...The problem of scheduling radar dwells in multifunction phased array radar systems is addressed. A novel dwell scheduling algorithm is proposed. The whole scheduling process is based on an online pulse interleaving technique. It takes the system timing and energy constraints into account. In order to adapt the dynamic task load, the algorithm considers both the priorities and deadlines of tasks. The simulation results demonstrate that compared with the conventional adaptive dwell scheduling algorithm, the proposed one can improve the task drop rate and system resource utility effectively.展开更多
An online pulse interleaving scheduling algorithm is proposed for a solution to the task scheduling problem in the digital array radar(DAR). The full DAR task structure is explicitly considered in a way that the waiti...An online pulse interleaving scheduling algorithm is proposed for a solution to the task scheduling problem in the digital array radar(DAR). The full DAR task structure is explicitly considered in a way that the waiting duration is able to be utilized to transmit or receive subtasks, namely the pulse interleaving,as well as the receiving durations of different tasks are able to be overlapped. The algorithm decomposes the pulse interleaving scheduling analysis into the time constraint check and the energy constraint check, and schedules online all kinds of tasks that are able to be interleaved. Thereby the waiting duration and the receiving duration in the DAR task are both fully utilized. The simulation results verify the performance improvement and the high efficiency of the proposed algorithm compared with the existing ones.展开更多
According to the signal processing characteristic of MIMO radars,an adaptive dwell scheduling algorithm is proposed.It is based on a novel pulse interleaving technique,which makes full use of transmitting,waiting and ...According to the signal processing characteristic of MIMO radars,an adaptive dwell scheduling algorithm is proposed.It is based on a novel pulse interleaving technique,which makes full use of transmitting,waiting and receiving durations of radar dwells.The utilization of transmitting duration is unique for MIMO radars and is realized through transmitting duration overlapping.Simulation results show that,compared with the conventional scheduling algorithm,the scheduling performance of MIMO radars can be improved effectively by the proposed algorithm,and the scheduling rule can be chosen arbitrarily when using the proposed algorithm.展开更多
To suppress the interference in the ultra-wideband (AI-UWB) system is a challenging problem. An anti-interference multiband orthogonal frequency-division multiplexing ultra-wideband (AI-UWB) system, based on sprea...To suppress the interference in the ultra-wideband (AI-UWB) system is a challenging problem. An anti-interference multiband orthogonal frequency-division multiplexing ultra-wideband (AI-UWB) system, based on spreading and interleaving is addressed. It will exploit the frequency diversity across the subcarriers and provide the robustness to narrow-band interference, by spreading the coded bit streams within each sub-band and interleaving across all sub-bands. Simulating results show that the spreading and interleaving provide about 5 dB to 10 dB advantages over the conventional multiband orthogonal frequency-division multiplexing ultra-wideband system in signal-to-interference ratio. Spreading and interleaving is an effective cure for enhancing the robustness to narrowband interference.展开更多
In this paper, we propose a packet-interleaving scheme (PIS) for increasing packet reliability under burst errors in wireless sensor networks (WSN). In a WSN, packet errors could occur due to weak signal strength or i...In this paper, we propose a packet-interleaving scheme (PIS) for increasing packet reliability under burst errors in wireless sensor networks (WSN). In a WSN, packet errors could occur due to weak signal strength or interference. These erroneous packets have to be retransmitted, which will increase network load substantially. The proposed PIS, encoding data using Reed-Solomon (RS) codes, can classify data into two different types: high-reliability-required (HRR) data and non-HRR data. An HRR packet is encoded with a short RS symbol, while a non-HRR packet with a long RS symbol. When an HRR and a non-HRR packet arrive at a sensor, they are interleaved on a symbol-by-symbol basis. Thus, the effect of burst errors (BE) is dispersed and consequently the uncorrectable HRR packets can be reduced. For the purpose of evaluation, two models, the uniform bit-error model (UBEM) and the on-off bit-error model (OBEM), are built to analyze the packet uncorrectable probability. In the evaluation, we first change the lengths of BE, then we vary the shift positions in a BE period, and finally we increase the number of correctable symbols to observe the superiority of the proposed PIS in reducing packet uncorrectable probability.展开更多
This paper evaluates the effect of decision feedback equalizer( DFE) error propagation for400 Gb/s Ethernet( 400 GbE) electrical link in order to propose some effective methods to improve bit error rate( BER). First,a...This paper evaluates the effect of decision feedback equalizer( DFE) error propagation for400 Gb/s Ethernet( 400 GbE) electrical link in order to propose some effective methods to improve bit error rate( BER). First,an analytical model for DFE burst error length distribution is proposed and simulated based on a NRZ electrical link in which a 5-tap DFE combined with a multiple-tap feed forward equalizer( FFE) is included. Then,a detailed derivation for BER considering DFE error propagation is given based on the distribution of burst error run length and the BER performance with and without forward error correction( FEC) is simulated too. After that,this paper investigates several MUX-based FEC interleaving methods including their complexity and latency in order to improve BER further. At last,three FEC interleaving schemes are compared not only in interleaving gain,but also in hardware complexities and latencies. Simulation results show that pre-interleave bit muxing can obtain good tradeoff between BER and complexity for 400 Gb E electrical link.展开更多
In MultiCarrier Code-Division Multiple-Access (MC-CDMA) system, the received signals scattered in the frequency domain are combined to get frequency diversity gain. However, the frequency diversity gain is limited bec...In MultiCarrier Code-Division Multiple-Access (MC-CDMA) system, the received signals scattered in the frequency domain are combined to get frequency diversity gain. However, the frequency diversity gain is limited because of correlation between aubcarriers. A novel interleaving scheme for MC-CDMA system is proposed in this paper. A circular shifting register is introduced into each subcarrier branch to decrease the correlation between subcarriers. By using interleaving, frequency diversity gain of system is increased. System structure and model with interleaver are discussed. In the case of multiple users, Parallel Interference Cancellation (PIC) technique is also introduced. Computer simulations demonstrate the performance of proposed scheme, and the performance comparison of MC-CDMA with interleaver and conventional MC-CDMA system is shown as well.展开更多
A kind of 2-phase interleaving coupled magnetic integrated VRM is studied and the corresponding passivity-based control strategy is put forward. The model of this kind of magnetic integrated VRM is constructed, and th...A kind of 2-phase interleaving coupled magnetic integrated VRM is studied and the corresponding passivity-based control strategy is put forward. The model of this kind of magnetic integrated VRM is constructed, and the performance of this 2-phase interleaving magnetic integrated VRM of passivity-based control is verified by simulation experiments. The results proved that this kind of passivity-based control strategy can decrease the steady state current ripple and the dynamic output voltage under load disturbance.展开更多
To improve the output characteristics of all-fiber Mach-Zehnder interferometer(MZI)-interleaver,a dual microring-assisted MZI interleaver is designed.According to its structure,the output expression of the device is d...To improve the output characteristics of all-fiber Mach-Zehnder interferometer(MZI)-interleaver,a dual microring-assisted MZI interleaver is designed.According to its structure,the output expression of the device is derived from the signal flow diagram.After simulation analysis,the optimal structural parameters during the transmission process are obtained.In addition,the coupling coefficient and transmission loss of the coupler are analyzed.The results show that the improved interleaver output line wave is closer to the square wave,and its 25 dB cutoff band bandwidth and 0.5 dB passband bandwidth are significantly improved,with the values of 41.2 GHz and 18.9 GHz,respectively.The device has a certain resistantability to deviation,and the transmission loss has less influence on the extinction characteristics of the filter.展开更多
The optimum choice of key parameters in the interleaving schemes used in RS codes/Viterbi-decoded convolutional codes concatenated coding systems is discussed. At the same time the simulation results and other optiona...The optimum choice of key parameters in the interleaving schemes used in RS codes/Viterbi-decoded convolutional codes concatenated coding systems is discussed. At the same time the simulation results and other optional interleaving schemes are given.展开更多
Quadrature Spatial Modulation (QSM) is a high spectral efficiency Multiple-Input Multiple Output (MIMO) technique used to improve the spectral efficiency of wireless communication systems. The main concept of QSM is t...Quadrature Spatial Modulation (QSM) is a high spectral efficiency Multiple-Input Multiple Output (MIMO) technique used to improve the spectral efficiency of wireless communication systems. The main concept of QSM is to extend the spatial constellation of the conventional Spatial Modulation (SM) in both the in-phase and quadrature components of the data symbol. In this paper, because QSM-based on Interleaxdng Division Multiplexing (IDM) has not been introduced in the literature as a multiple antenna system, we introduced a novel scheme, called QSM system based on Interleaving Division Multiplexing (QSM-IDM). The antenna sets are also applied to a spreader, before being used to assign an antenna number for information transmission. Analysis and simulations for a flat fading channel show that the proposed QSM-IDM method significantly outperforms the original QSM system with the same data rate, while maintaining a relatively acceptable complexity. The obtained simulation results show that the conducted analysis yields significant improvements for the accuracy of the proposed scheme, with satisfactory complexity.展开更多
In the investigation of turbo codes, either random interleavers or structured interleavers are used. Combined two kinds of interleavers in one turbo encoder, a hybrid interleaving mode is proposed in this paper. Compu...In the investigation of turbo codes, either random interleavers or structured interleavers are used. Combined two kinds of interleavers in one turbo encoder, a hybrid interleaving mode is proposed in this paper. Computer simulations show that the performance of turbo codes with the hybrid interleaving mode is better than that with the typical interleaving mode.展开更多
Triple-level cell(TLC)NAND flash is increasingly adopted to build solid-state drives(SSDs)for modern computer systems.While TLC NAND flash effectively improves storage density,it faces severe reliability issues;in par...Triple-level cell(TLC)NAND flash is increasingly adopted to build solid-state drives(SSDs)for modern computer systems.While TLC NAND flash effectively improves storage density,it faces severe reliability issues;in partic-ular,the pages exhibit different raw bit error rates(RBERs).Integrating strong low-density parity-check(LDPC)code helps to improve reliability but suffers from prolonged and proportional read latency due to multiple read retries for worse pages.The straightforward idea is that dispersing page-size data across several pages in different types can achieve a low-er average RBER and reduce the read latency.However,directly implementing this simple idea into flash translation lay-er(FTL)induces the read amplification issue as one logic page residing in more than one physical page brings several read operations.In this paper,we propose the Dynamic Request Interleaving(DIR)technology for improving the performance of TLC NAND flash-based SSDs,in particular,the aged ones with large RBERs.DIR exploits the observation that the la-tency of an I/O request is determined,without considering the queuing time,by the access of the slowest device page,i.e.,the page that has the highest RBER.By grouping consecutive logical pages that have high locality and interleaving their encoded data in different types of device pages that have different RBERs,DIR effectively reduces the number of read re-tries for LDPC with limited read amplification.To meet the requirement of allocating hybrid page types for interleaved data,we also design a page-interleaving friendly page allocation scheme,which splits all the planes into multi-plane re-gions for storing the interleaved data and single-plane regions for storing the normal data.The pages in the multi-plane re-gion can be read/written in parallel by the proposed multi-plane command and avoid the read amplification issue.Based on the DIR scheme and the proposed page allocation scheme,we build DIR-enable FTL,which integrates the proposed schemes into the FTL with some modifications.Our experimental results show that adopting DIR in aged SSDs exploits nearly 33%locality from I/O requests and,on average,reduces 43%read latency over conventional aged SSDs.展开更多
Compressive strengths and elastic moduli of Carbon Fiber Reinforced Polymer(CFRP)composites can be noticeably improved by multiple ultra-thin interlays with non-woven Aramid Pulp(AP)micro/nano-fibers.10-ply CFRP speci...Compressive strengths and elastic moduli of Carbon Fiber Reinforced Polymer(CFRP)composites can be noticeably improved by multiple ultra-thin interlays with non-woven Aramid Pulp(AP)micro/nano-fibers.10-ply CFRP specimens with 0,2,4,6,8 g/m^(2)AP were tested under uniaxial compression.Those flexible AP fibers,filling the resin-rich regions and further constructing the fiber bridging at the ply interfaces,can effectively suppress delamination growth and lead to very good improvements both in the compressive strength and the elastic modulus.The CFRP specimen with an optimum interlay thickness has a distinct shear failure mode instead of the typical delamination cracking along the direction of continuous carbon fibers.Compressive Strengths After Impacts(CAI)of 12.35 J were also measured,up to 90%improvement in CAI has been observed.It is concluded those ultra-thin interlays of non-woven AP micro/nano-fibers are beneficial to design and manufacture“high strength”CFRP composites.展开更多
An interference suppression design scheme based on conjugate weighted butterfly interleaving mapping(CWBIM)is proposed for inter-carrier interference(ICI)and inter-subband interference(IBI)in the received signals of u...An interference suppression design scheme based on conjugate weighted butterfly interleaving mapping(CWBIM)is proposed for inter-carrier interference(ICI)and inter-subband interference(IBI)in the received signals of universal filtered multi-carrier(UFMC)systems.It applies an interleaving mapping operation to subtract the interference coefficients of adjacent terms in ICI and IBI twice,thereby achieving suppression effects similar to the self-cancellation(SC)algorithm while maintaining the original data transmission efficiency.Meanwhile,conjugate and complex weighting operations can effectively suppress the impact of phase rotation errors in high-speed mobile channel environments,thereby further improving the bit error rate(BFR)performance of the system,Moreover,butterfly operation can effectively control the computational complexity of the interleaving mapping process.Theoretical analysis and simulation results show that,compared with the PSC-UFMC algorithm,the CWBIM-UFMC scheme proposed in this paper can effectively suppress ICI and IBI in the received signal without compromising data transmission efficiency and reducing computational complexity,thereby achieving good BER performance of the system.展开更多
In this research, unidirectional flax fabrics reinforced epoxy laminates were intedeaved with randomly oriented chopped flax yarns at various yarn lengths and contents. Mode I interlaminar fracture toughness of the la...In this research, unidirectional flax fabrics reinforced epoxy laminates were intedeaved with randomly oriented chopped flax yarns at various yarn lengths and contents. Mode I interlaminar fracture toughness of the laminates was evaluated via Double Cantilever Beam (DCB) tests. The results showed that Mode I interlaminar fracture toughness increased with the introduction of the chopped yarns. With moderate yarn length and content, the best toughening effect (31% improvement in Mode I inter- laminar fracture toughness) was achieved. It was observed with the aid of Scanning Electronic Microscopy (SEM) that the in- troduction of the chopped yarns resulted in more tortuous in-plane crack propagation paths as well as the "trans-layer" phe- nomenon and fiber bridging effect of both the unidirectional yams and the chopped yams. These hindered the growth of the crack and led to more energy dissipation during delamination progress. Excessive yam length or content would induce unstable crack propagation and thus weakened the toughening improvement. No remarkable change was found in the tensile properties and the Charpy impact strength for the interleaved laminates, which indicated that this interleaving method was effective on interlaminar toughening without sacrificing the comprehensive mechanical properties of the laminates.展开更多
Optical metasurfaces,comprising subwavelength quasi-planar nanostructures,constitute a universal platform for manipulating the amplitude,phase,and polarization of light,thus paving a way for the next generation of hig...Optical metasurfaces,comprising subwavelength quasi-planar nanostructures,constitute a universal platform for manipulating the amplitude,phase,and polarization of light,thus paving a way for the next generation of highly integrated multifunctional optical devices.In this work,we introduce a reflective metasurface for the generation of a complete(angularly resolved)polarization set by randomly interleaving anisotropic plasmonic meta-atoms acting as nanoscale wave plates.In the proof-of-concept demonstration,we achieve multidirectional beam-steering into different polarization channels forming a complete set of polarization states,which can also be dynamically altered by switching the spin of incident light.The developed design concept represents a significant advancement in achieving flat polarization optics with advanced functionalities.展开更多
文摘The interleaving/multiplexing technique was used to realize a 200?MHz real time data acquisition system. Two 100?MHz ADC modules worked parallelly and every ADC plays out data in ping pang fashion. The design improved the system conversion rata to 200?MHz and reduced the speed of data transporting and storing to 50?MHz. The high speed HDPLD and ECL logic parts were used to control system timing and the memory address. The multi layer print board and the shield were used to decrease interference produced by the high speed circuit. The system timing was designed carefully. The interleaving/multiplexing technique could improve the system conversion rata greatly while reducing the speed of external digital interfaces greatly. The design resolved the difficulties in high speed system effectively. The experiment proved the data acquisition system is stable and accurate.
文摘A novel interleaving based selected mapping (SLM) scheme to depress the relatively high peak power of transmit signals in multicarrier communications is proposed. In the scheme, a group of bit-level interleavers spanning only a few bits are used to produce multiple sequences representing the same information, and one of the sequences resulting in the lowest peak-to-average power ratio (PAPR) is selected for transmission. The implementation of the scheme including the structure of the short-span interleaver is illustrated. The performance of this PAPR reduction scheme is investigated by simulations. This scheme exhibits a good PAPR reduction performance, and for signals of high level modulation, such as 16QAM and 64QAM, it approaches the best performance of all SLM schemes. Compared to the conventional interleaving SLM, this short-span interleaving SLM results in a very short time delay, requires very few register units for buffering, and can be easily implemented by hardware.
文摘The problem of scheduling radar dwells in multifunction phased array radar systems is addressed. A novel dwell scheduling algorithm is proposed. The whole scheduling process is based on an online pulse interleaving technique. It takes the system timing and energy constraints into account. In order to adapt the dynamic task load, the algorithm considers both the priorities and deadlines of tasks. The simulation results demonstrate that compared with the conventional adaptive dwell scheduling algorithm, the proposed one can improve the task drop rate and system resource utility effectively.
文摘An online pulse interleaving scheduling algorithm is proposed for a solution to the task scheduling problem in the digital array radar(DAR). The full DAR task structure is explicitly considered in a way that the waiting duration is able to be utilized to transmit or receive subtasks, namely the pulse interleaving,as well as the receiving durations of different tasks are able to be overlapped. The algorithm decomposes the pulse interleaving scheduling analysis into the time constraint check and the energy constraint check, and schedules online all kinds of tasks that are able to be interleaved. Thereby the waiting duration and the receiving duration in the DAR task are both fully utilized. The simulation results verify the performance improvement and the high efficiency of the proposed algorithm compared with the existing ones.
基金supported by the National Natural Science Foundation of China(6110117161032010)
文摘According to the signal processing characteristic of MIMO radars,an adaptive dwell scheduling algorithm is proposed.It is based on a novel pulse interleaving technique,which makes full use of transmitting,waiting and receiving durations of radar dwells.The utilization of transmitting duration is unique for MIMO radars and is realized through transmitting duration overlapping.Simulation results show that,compared with the conventional scheduling algorithm,the scheduling performance of MIMO radars can be improved effectively by the proposed algorithm,and the scheduling rule can be chosen arbitrarily when using the proposed algorithm.
基金the National "863" High Technology Research Program of China (2005AA123320)Universities Natural Science Research Project of Jiangsu Province (05KJB510101).
文摘To suppress the interference in the ultra-wideband (AI-UWB) system is a challenging problem. An anti-interference multiband orthogonal frequency-division multiplexing ultra-wideband (AI-UWB) system, based on spreading and interleaving is addressed. It will exploit the frequency diversity across the subcarriers and provide the robustness to narrow-band interference, by spreading the coded bit streams within each sub-band and interleaving across all sub-bands. Simulating results show that the spreading and interleaving provide about 5 dB to 10 dB advantages over the conventional multiband orthogonal frequency-division multiplexing ultra-wideband system in signal-to-interference ratio. Spreading and interleaving is an effective cure for enhancing the robustness to narrowband interference.
文摘In this paper, we propose a packet-interleaving scheme (PIS) for increasing packet reliability under burst errors in wireless sensor networks (WSN). In a WSN, packet errors could occur due to weak signal strength or interference. These erroneous packets have to be retransmitted, which will increase network load substantially. The proposed PIS, encoding data using Reed-Solomon (RS) codes, can classify data into two different types: high-reliability-required (HRR) data and non-HRR data. An HRR packet is encoded with a short RS symbol, while a non-HRR packet with a long RS symbol. When an HRR and a non-HRR packet arrive at a sensor, they are interleaved on a symbol-by-symbol basis. Thus, the effect of burst errors (BE) is dispersed and consequently the uncorrectable HRR packets can be reduced. For the purpose of evaluation, two models, the uniform bit-error model (UBEM) and the on-off bit-error model (OBEM), are built to analyze the packet uncorrectable probability. In the evaluation, we first change the lengths of BE, then we vary the shift positions in a BE period, and finally we increase the number of correctable symbols to observe the superiority of the proposed PIS in reducing packet uncorrectable probability.
基金Supported by the National Natural Science Foundation of China(No.61471119)
文摘This paper evaluates the effect of decision feedback equalizer( DFE) error propagation for400 Gb/s Ethernet( 400 GbE) electrical link in order to propose some effective methods to improve bit error rate( BER). First,an analytical model for DFE burst error length distribution is proposed and simulated based on a NRZ electrical link in which a 5-tap DFE combined with a multiple-tap feed forward equalizer( FFE) is included. Then,a detailed derivation for BER considering DFE error propagation is given based on the distribution of burst error run length and the BER performance with and without forward error correction( FEC) is simulated too. After that,this paper investigates several MUX-based FEC interleaving methods including their complexity and latency in order to improve BER further. At last,three FEC interleaving schemes are compared not only in interleaving gain,but also in hardware complexities and latencies. Simulation results show that pre-interleave bit muxing can obtain good tradeoff between BER and complexity for 400 Gb E electrical link.
文摘In MultiCarrier Code-Division Multiple-Access (MC-CDMA) system, the received signals scattered in the frequency domain are combined to get frequency diversity gain. However, the frequency diversity gain is limited because of correlation between aubcarriers. A novel interleaving scheme for MC-CDMA system is proposed in this paper. A circular shifting register is introduced into each subcarrier branch to decrease the correlation between subcarriers. By using interleaving, frequency diversity gain of system is increased. System structure and model with interleaver are discussed. In the case of multiple users, Parallel Interference Cancellation (PIC) technique is also introduced. Computer simulations demonstrate the performance of proposed scheme, and the performance comparison of MC-CDMA with interleaver and conventional MC-CDMA system is shown as well.
文摘A kind of 2-phase interleaving coupled magnetic integrated VRM is studied and the corresponding passivity-based control strategy is put forward. The model of this kind of magnetic integrated VRM is constructed, and the performance of this 2-phase interleaving magnetic integrated VRM of passivity-based control is verified by simulation experiments. The results proved that this kind of passivity-based control strategy can decrease the steady state current ripple and the dynamic output voltage under load disturbance.
基金National Natural Science Foundation of China(No.61461024)Foundation of a Hundred Youth Talent Training Program of Lanzhou Jiaotong University(No.1520220232)。
文摘To improve the output characteristics of all-fiber Mach-Zehnder interferometer(MZI)-interleaver,a dual microring-assisted MZI interleaver is designed.According to its structure,the output expression of the device is derived from the signal flow diagram.After simulation analysis,the optimal structural parameters during the transmission process are obtained.In addition,the coupling coefficient and transmission loss of the coupler are analyzed.The results show that the improved interleaver output line wave is closer to the square wave,and its 25 dB cutoff band bandwidth and 0.5 dB passband bandwidth are significantly improved,with the values of 41.2 GHz and 18.9 GHz,respectively.The device has a certain resistantability to deviation,and the transmission loss has less influence on the extinction characteristics of the filter.
文摘The optimum choice of key parameters in the interleaving schemes used in RS codes/Viterbi-decoded convolutional codes concatenated coding systems is discussed. At the same time the simulation results and other optional interleaving schemes are given.
文摘Quadrature Spatial Modulation (QSM) is a high spectral efficiency Multiple-Input Multiple Output (MIMO) technique used to improve the spectral efficiency of wireless communication systems. The main concept of QSM is to extend the spatial constellation of the conventional Spatial Modulation (SM) in both the in-phase and quadrature components of the data symbol. In this paper, because QSM-based on Interleaxdng Division Multiplexing (IDM) has not been introduced in the literature as a multiple antenna system, we introduced a novel scheme, called QSM system based on Interleaving Division Multiplexing (QSM-IDM). The antenna sets are also applied to a spreader, before being used to assign an antenna number for information transmission. Analysis and simulations for a flat fading channel show that the proposed QSM-IDM method significantly outperforms the original QSM system with the same data rate, while maintaining a relatively acceptable complexity. The obtained simulation results show that the conducted analysis yields significant improvements for the accuracy of the proposed scheme, with satisfactory complexity.
文摘In the investigation of turbo codes, either random interleavers or structured interleavers are used. Combined two kinds of interleavers in one turbo encoder, a hybrid interleaving mode is proposed in this paper. Computer simulations show that the performance of turbo codes with the hybrid interleaving mode is better than that with the typical interleaving mode.
基金This work was supported by the National Key Research and Development Project of China under Grant No.2017YFB1001701the National Natural Science Foundation of China under Grant No.61972311in part by Shandong Provincial Natural Science Foundation of China under Grant No.ZR2019LZH007.
文摘Triple-level cell(TLC)NAND flash is increasingly adopted to build solid-state drives(SSDs)for modern computer systems.While TLC NAND flash effectively improves storage density,it faces severe reliability issues;in partic-ular,the pages exhibit different raw bit error rates(RBERs).Integrating strong low-density parity-check(LDPC)code helps to improve reliability but suffers from prolonged and proportional read latency due to multiple read retries for worse pages.The straightforward idea is that dispersing page-size data across several pages in different types can achieve a low-er average RBER and reduce the read latency.However,directly implementing this simple idea into flash translation lay-er(FTL)induces the read amplification issue as one logic page residing in more than one physical page brings several read operations.In this paper,we propose the Dynamic Request Interleaving(DIR)technology for improving the performance of TLC NAND flash-based SSDs,in particular,the aged ones with large RBERs.DIR exploits the observation that the la-tency of an I/O request is determined,without considering the queuing time,by the access of the slowest device page,i.e.,the page that has the highest RBER.By grouping consecutive logical pages that have high locality and interleaving their encoded data in different types of device pages that have different RBERs,DIR effectively reduces the number of read re-tries for LDPC with limited read amplification.To meet the requirement of allocating hybrid page types for interleaved data,we also design a page-interleaving friendly page allocation scheme,which splits all the planes into multi-plane re-gions for storing the interleaved data and single-plane regions for storing the normal data.The pages in the multi-plane re-gion can be read/written in parallel by the proposed multi-plane command and avoid the read amplification issue.Based on the DIR scheme and the proposed page allocation scheme,we build DIR-enable FTL,which integrates the proposed schemes into the FTL with some modifications.Our experimental results show that adopting DIR in aged SSDs exploits nearly 33%locality from I/O requests and,on average,reduces 43%read latency over conventional aged SSDs.
基金the National Natural Science Foundation of China(No.52102115)the Fundamental Research Funds of Southwestern University of Science and Technology,China(No.20zx7141).
文摘Compressive strengths and elastic moduli of Carbon Fiber Reinforced Polymer(CFRP)composites can be noticeably improved by multiple ultra-thin interlays with non-woven Aramid Pulp(AP)micro/nano-fibers.10-ply CFRP specimens with 0,2,4,6,8 g/m^(2)AP were tested under uniaxial compression.Those flexible AP fibers,filling the resin-rich regions and further constructing the fiber bridging at the ply interfaces,can effectively suppress delamination growth and lead to very good improvements both in the compressive strength and the elastic modulus.The CFRP specimen with an optimum interlay thickness has a distinct shear failure mode instead of the typical delamination cracking along the direction of continuous carbon fibers.Compressive Strengths After Impacts(CAI)of 12.35 J were also measured,up to 90%improvement in CAI has been observed.It is concluded those ultra-thin interlays of non-woven AP micro/nano-fibers are beneficial to design and manufacture“high strength”CFRP composites.
基金Supported by the National Natural Science Foundation of China(No.61601296,61701295)the Science and Technology Innovation ActionPlan Project of Shanghai Science and Technology Commission(No.20511103500)the Talent Program of Shanghai University of Engineer-ing Science(No.2018RC43)。
文摘An interference suppression design scheme based on conjugate weighted butterfly interleaving mapping(CWBIM)is proposed for inter-carrier interference(ICI)and inter-subband interference(IBI)in the received signals of universal filtered multi-carrier(UFMC)systems.It applies an interleaving mapping operation to subtract the interference coefficients of adjacent terms in ICI and IBI twice,thereby achieving suppression effects similar to the self-cancellation(SC)algorithm while maintaining the original data transmission efficiency.Meanwhile,conjugate and complex weighting operations can effectively suppress the impact of phase rotation errors in high-speed mobile channel environments,thereby further improving the bit error rate(BFR)performance of the system,Moreover,butterfly operation can effectively control the computational complexity of the interleaving mapping process.Theoretical analysis and simulation results show that,compared with the PSC-UFMC algorithm,the CWBIM-UFMC scheme proposed in this paper can effectively suppress ICI and IBI in the received signal without compromising data transmission efficiency and reducing computational complexity,thereby achieving good BER performance of the system.
基金supported the National Basic Research Program of China("973"Project)(Grant No.2010CB631105)
文摘In this research, unidirectional flax fabrics reinforced epoxy laminates were intedeaved with randomly oriented chopped flax yarns at various yarn lengths and contents. Mode I interlaminar fracture toughness of the laminates was evaluated via Double Cantilever Beam (DCB) tests. The results showed that Mode I interlaminar fracture toughness increased with the introduction of the chopped yarns. With moderate yarn length and content, the best toughening effect (31% improvement in Mode I inter- laminar fracture toughness) was achieved. It was observed with the aid of Scanning Electronic Microscopy (SEM) that the in- troduction of the chopped yarns resulted in more tortuous in-plane crack propagation paths as well as the "trans-layer" phe- nomenon and fiber bridging effect of both the unidirectional yams and the chopped yams. These hindered the growth of the crack and led to more energy dissipation during delamination progress. Excessive yam length or content would induce unstable crack propagation and thus weakened the toughening improvement. No remarkable change was found in the tensile properties and the Charpy impact strength for the interleaved laminates, which indicated that this interleaving method was effective on interlaminar toughening without sacrificing the comprehensive mechanical properties of the laminates.
基金funded by the Danmarks Frie Forskningsfond(1134-00010B)Villum Fonden(Award in Technical and Natural Sciences 2019 and Grant No.37372)Y.Deng would like to acknowledge the support from the China Scholarship Council(Grant No.202108330079).
文摘Optical metasurfaces,comprising subwavelength quasi-planar nanostructures,constitute a universal platform for manipulating the amplitude,phase,and polarization of light,thus paving a way for the next generation of highly integrated multifunctional optical devices.In this work,we introduce a reflective metasurface for the generation of a complete(angularly resolved)polarization set by randomly interleaving anisotropic plasmonic meta-atoms acting as nanoscale wave plates.In the proof-of-concept demonstration,we achieve multidirectional beam-steering into different polarization channels forming a complete set of polarization states,which can also be dynamically altered by switching the spin of incident light.The developed design concept represents a significant advancement in achieving flat polarization optics with advanced functionalities.