In the bit-interleaved coded modulation with iterative decoding,it is desired that any two Hamming neighbors,i.e..signal constellation points whose binary labels are at unit Hamming distance,be separated by a large Eu...In the bit-interleaved coded modulation with iterative decoding,it is desired that any two Hamming neighbors,i.e..signal constellation points whose binary labels are at unit Hamming distance,be separated by a large Euclidean distance.This paper determines the mappings for the 32-ary fourdimensional generalized cross constellation（32-4D-GCC） so that the minimum squared Euclidean distance d_（min）~2 between Hamming neighbors is maximized.Among such mappings,those with minimum multiplicity N（d_（min）~2） are selected.To reduce the large search space,a set of ＂mapping templates,＂ each producing a collection of mappings with the same set partitions of binary labels,is introduced.Via enumeration of mapping templates,it is shown that the optimum d_（min）~2=16and the optimum N（d_（min）~2）=16.Among thousands optimum mappings found by computer search,two of the best performance are presented.展开更多
Programmable metasurface enables controlling electromagnetic (EM) waves in real time. By programming the states of active device embedded in metasurface element, the EM properties of the digital metasurface can be cha...Programmable metasurface enables controlling electromagnetic (EM) waves in real time. By programming the states of active device embedded in metasurface element, the EM properties of the digital metasurface can be changed quickly without redesigning their structures. However, large numbers of long-distance wires are required to connect the programmable metasurface to provide the coded signals from field programmable gate array (FPGA) when controlling the metasurface at a long distance, which is complicated and inconvenient. Here, we propose an infrared-controlled programmable metasurface that can be programmed remotely. The infrared transceiver is able to switch the coding sequences stored in the FPGA controller, thus controlling the voltage on the varactors integrated in the metasurface. Experiment is performed at microwave frequencies, and the measured results verify that the scattering beams of the metasurface sample can be changed remotely by using infrared ray. The proposed infrared-controlled programmable metasurface opens up avenues for constructing a new class of remotely-tuning dynamic metasurfaces.展开更多
An offset quadrature amplitude modulation orthogonal frequency-division multiplexing(OQAM-OFDM) passive optical network(PON) architecture with direct detection is brought up to increase the transmission range and impr...An offset quadrature amplitude modulation orthogonal frequency-division multiplexing(OQAM-OFDM) passive optical network(PON) architecture with direct detection is brought up to increase the transmission range and improve the system performance.In optical line terminal(OLT),OQAM-OFDM signals at 40 Gbit/s are transmitted as downstream.At each optical network unit(ONU),the optical OQAM-OFDM signal is demodulated with direct detection.The results show that the transmission distance can exceed 20 km with negligible penalty under the experimental conditions.展开更多
基金supported by the National Key Basic Research Program of China(973 program) under grant No.2010CB328206NSFC under grants No.60837002+3 种基金60807003and 61102048the Fundamental Research Funds for the Central Universities under grant No.2011JBM208NSF under grant CCF-0952711
文摘In the bit-interleaved coded modulation with iterative decoding,it is desired that any two Hamming neighbors,i.e..signal constellation points whose binary labels are at unit Hamming distance,be separated by a large Euclidean distance.This paper determines the mappings for the 32-ary fourdimensional generalized cross constellation（32-4D-GCC） so that the minimum squared Euclidean distance d_（min）~2 between Hamming neighbors is maximized.Among such mappings,those with minimum multiplicity N（d_（min）~2） are selected.To reduce the large search space,a set of ＂mapping templates,＂ each producing a collection of mappings with the same set partitions of binary labels,is introduced.Via enumeration of mapping templates,it is shown that the optimum d_（min）~2=16and the optimum N（d_（min）~2）=16.Among thousands optimum mappings found by computer search,two of the best performance are presented.
基金This work was supported by the National Key Research and Development Program of China(2017YFA0700201,2017YFA0700203 and 2016YFC0800401)National Natural Science Foundation of China(61890544,61522106,61631007,61571117,61731010,61735010,61722106,61701107,and 61701108)+3 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX19_0081)Scientific Research Foundation of Graduate School of Southeast University(YBPY1938)Foundation of National Excellent Doctoral Dissertation of China(201444)the 111 Project(111-2-05).
文摘Programmable metasurface enables controlling electromagnetic (EM) waves in real time. By programming the states of active device embedded in metasurface element, the EM properties of the digital metasurface can be changed quickly without redesigning their structures. However, large numbers of long-distance wires are required to connect the programmable metasurface to provide the coded signals from field programmable gate array (FPGA) when controlling the metasurface at a long distance, which is complicated and inconvenient. Here, we propose an infrared-controlled programmable metasurface that can be programmed remotely. The infrared transceiver is able to switch the coding sequences stored in the FPGA controller, thus controlling the voltage on the varactors integrated in the metasurface. Experiment is performed at microwave frequencies, and the measured results verify that the scattering beams of the metasurface sample can be changed remotely by using infrared ray. The proposed infrared-controlled programmable metasurface opens up avenues for constructing a new class of remotely-tuning dynamic metasurfaces.
基金supported by the National Natural Science Foundation of China(No.61431009)the Natural Science Foundation of Shandong Province(No.ZR2014FL002)
文摘An offset quadrature amplitude modulation orthogonal frequency-division multiplexing(OQAM-OFDM) passive optical network(PON) architecture with direct detection is brought up to increase the transmission range and improve the system performance.In optical line terminal(OLT),OQAM-OFDM signals at 40 Gbit/s are transmitted as downstream.At each optical network unit(ONU),the optical OQAM-OFDM signal is demodulated with direct detection.The results show that the transmission distance can exceed 20 km with negligible penalty under the experimental conditions.
