Sparse code multiple access(SCMA) is a novel non-orthogonal multiple access scheme proposed to meet the challenging demand of the future 5G communications, especially in support of the massive connections. The coded b...Sparse code multiple access(SCMA) is a novel non-orthogonal multiple access scheme proposed to meet the challenging demand of the future 5G communications, especially in support of the massive connections. The coded bits from each data stream will be directly mapped as multi-dimensional SCMA codeword in complex domain and then spread onto the physical resource elements in a sparse manner. The number of codewords that can be nonorthogonally multiplexed in one SCMA block can be made much larger than the number of orthogonal resource elements therein, resulting in an overloaded system. The sparsity in the spreading pattern and the design in the multidimensional modulator jointly ensure the SCMA codewords can be robustly decoded with low complexity. In this paper, we focus on the low complexity receiver design and verified the superior of an SCMA system via simulations and real-time prototyping. Lab tests and field tests all show that SCMA is a promising candidate for 5G non-orthogonal multiple access which can provide up to 300% overloading that triples the whole system throughput while still enjoying the link performance close to orthogonal transmissions.展开更多
Wirreless sensor networks are being widely researched and are expected to be used in several scenarios. On the leading edge of treads, on-demand, high-reliability, and low-latency routing protocol is desirable for ind...Wirreless sensor networks are being widely researched and are expected to be used in several scenarios. On the leading edge of treads, on-demand, high-reliability, and low-latency routing protocol is desirable for indoor environment applications. This article proposes a routing scheme called robust multi-path routing that establishes and uses multiple node-disjoint routes. Providing multiple routes helps to reduce the route recovery process and control the message overhead. The performance comparison of this protocol with dynamic source routing （DSR） by OPNET simulations shows that this protocol is able to achieve a remarkable improvement in the packet delivery ratio and average end-to-end delay.展开更多
针对远距离遥感数据传输过程中存在的网络通信高时延、带宽利用率低等问题,在基于TCP(transmission control protocol)和UDP(user datagram protocol)的基础上,提出了一种新型数据传输协议--FRUDP(feedback retransmission user data pr...针对远距离遥感数据传输过程中存在的网络通信高时延、带宽利用率低等问题,在基于TCP(transmission control protocol)和UDP(user datagram protocol)的基础上,提出了一种新型数据传输协议--FRUDP(feedback retransmission user data protocol).该协议依据链路条件将待发数据分包、分组,发送方根据接收方IP地址及对应端口,依序集中发送数据组包及反馈重传包,接收方通过接收、解析数据包头,遍历统计得出数据包接收情况,进而反馈重传统计结果,轮询发送、接收反馈操作直到接收完成.该协议有效地保证了传输数据的准确性,并且使发送方性能获得极大提升,提高了高时延链路环境下的带宽利用率.测试实验结果表明:FRUDP能够有效保障高时延链路条件下的带宽利用率.展开更多
Dynamic fluorescent materials play a crucial role in secure inks for data encryption;however,they are still plagued by issues such as photodegradation,poor latency,and susceptibility to unauthorized access.Herein,we p...Dynamic fluorescent materials play a crucial role in secure inks for data encryption;however,they are still plagued by issues such as photodegradation,poor latency,and susceptibility to unauthorized access.Herein,we propose a photochemically modulated dynamic fluorescent encryption system based on^(1)O_(2)sensitization of fluorescent composites,comprising a^(1)O_(2)-sensitive fluorophore(F2)and non-emissive polymers.After UV irradiation,in-situ generated^(1)O_(2)from the polymer effectively binds with F2 to form endoperoxides(F2EPO),resulting in a significant redshift in emission,up to 150 nm.The^(1)O_(2)concentration is closely related to the irradiation time,rendering different fluorescent colors in a time-gated fashion.Moreover,the emission of F2EPO can be regulated by polymer chemical structure,molecular weight,and crosslinking density.Relying on these merits,we develop a dynamic data encryption method with various non-emissive polymers as the data storage media,UV light irradiation as the data encoder,and F2 as the data decoder.UV light irradiation of diverse polymer solutions generates^(1)O_(2)at different concentrations,effectively encoding the data,which remains invisible under both UV and natural lights.The addition of F2 to these irradiated polymer solutions produces different redshifted fluorescence,enabling secure data decryption.Attributing to the non-emissive nature of the polymers,time-gated readout fashion,excellent latency of^(1)O_(2),and subtle interactions between^(1)O_(2)and F2,this data encryption is nearly undecipherable.This work offers an advantage data encryption approach beyond the reach of conventional fluorophores.展开更多
文摘Sparse code multiple access(SCMA) is a novel non-orthogonal multiple access scheme proposed to meet the challenging demand of the future 5G communications, especially in support of the massive connections. The coded bits from each data stream will be directly mapped as multi-dimensional SCMA codeword in complex domain and then spread onto the physical resource elements in a sparse manner. The number of codewords that can be nonorthogonally multiplexed in one SCMA block can be made much larger than the number of orthogonal resource elements therein, resulting in an overloaded system. The sparsity in the spreading pattern and the design in the multidimensional modulator jointly ensure the SCMA codewords can be robustly decoded with low complexity. In this paper, we focus on the low complexity receiver design and verified the superior of an SCMA system via simulations and real-time prototyping. Lab tests and field tests all show that SCMA is a promising candidate for 5G non-orthogonal multiple access which can provide up to 300% overloading that triples the whole system throughput while still enjoying the link performance close to orthogonal transmissions.
文摘Wirreless sensor networks are being widely researched and are expected to be used in several scenarios. On the leading edge of treads, on-demand, high-reliability, and low-latency routing protocol is desirable for indoor environment applications. This article proposes a routing scheme called robust multi-path routing that establishes and uses multiple node-disjoint routes. Providing multiple routes helps to reduce the route recovery process and control the message overhead. The performance comparison of this protocol with dynamic source routing （DSR） by OPNET simulations shows that this protocol is able to achieve a remarkable improvement in the packet delivery ratio and average end-to-end delay.
文摘针对远距离遥感数据传输过程中存在的网络通信高时延、带宽利用率低等问题,在基于TCP(transmission control protocol)和UDP(user datagram protocol)的基础上,提出了一种新型数据传输协议--FRUDP(feedback retransmission user data protocol).该协议依据链路条件将待发数据分包、分组,发送方根据接收方IP地址及对应端口,依序集中发送数据组包及反馈重传包,接收方通过接收、解析数据包头,遍历统计得出数据包接收情况,进而反馈重传统计结果,轮询发送、接收反馈操作直到接收完成.该协议有效地保证了传输数据的准确性,并且使发送方性能获得极大提升,提高了高时延链路环境下的带宽利用率.测试实验结果表明:FRUDP能够有效保障高时延链路条件下的带宽利用率.
基金supported by the National Natural Science Foundation of China(22275193 and 52303355)the Natural Science Foundation of Fujian Province(2021J06034)+2 种基金Self-deployment Project Research Program of Haixi Institutes,Chinese Academy of Science,CXZX-2022-GH09(E255KF0101)Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences(E055AJ01)the STS Project of Fujian-CAS(Grant No.:2023T3027).
文摘Dynamic fluorescent materials play a crucial role in secure inks for data encryption;however,they are still plagued by issues such as photodegradation,poor latency,and susceptibility to unauthorized access.Herein,we propose a photochemically modulated dynamic fluorescent encryption system based on^(1)O_(2)sensitization of fluorescent composites,comprising a^(1)O_(2)-sensitive fluorophore(F2)and non-emissive polymers.After UV irradiation,in-situ generated^(1)O_(2)from the polymer effectively binds with F2 to form endoperoxides(F2EPO),resulting in a significant redshift in emission,up to 150 nm.The^(1)O_(2)concentration is closely related to the irradiation time,rendering different fluorescent colors in a time-gated fashion.Moreover,the emission of F2EPO can be regulated by polymer chemical structure,molecular weight,and crosslinking density.Relying on these merits,we develop a dynamic data encryption method with various non-emissive polymers as the data storage media,UV light irradiation as the data encoder,and F2 as the data decoder.UV light irradiation of diverse polymer solutions generates^(1)O_(2)at different concentrations,effectively encoding the data,which remains invisible under both UV and natural lights.The addition of F2 to these irradiated polymer solutions produces different redshifted fluorescence,enabling secure data decryption.Attributing to the non-emissive nature of the polymers,time-gated readout fashion,excellent latency of^(1)O_(2),and subtle interactions between^(1)O_(2)and F2,this data encryption is nearly undecipherable.This work offers an advantage data encryption approach beyond the reach of conventional fluorophores.
