Information embodied in machine component classification codes has internal relation with the probability distribu- tion of the code symbol. This paper presents a model considering codes as information source based on...Information embodied in machine component classification codes has internal relation with the probability distribu- tion of the code symbol. This paper presents a model considering codes as information source based on Shannon’s information theory. Using information entropy, it preserves the mathematical form and quantitatively measures the information amount of a symbol and a bit in the machine component classification coding system. It also gets the maximum value of information amount and the corresponding coding scheme when the category of symbols is fixed. Samples are given to show how to evaluate the information amount of component codes and how to optimize a coding system.展开更多
Pilot needs to process lots of information when operating an aircraft, and reasonable information coding can greatly improve the correct rate and speed of information identification. At present, related researches are...Pilot needs to process lots of information when operating an aircraft, and reasonable information coding can greatly improve the correct rate and speed of information identification. At present, related researches are mainly performed in the laboratory, and the experiment method for abstract simulation is often used to research single digit information coding. The research results demonstrate a lack of systematization and applicability. The present study is based upon information coding methods of human-machine interface under real time in flight simulators. Subjects are required to perform an aircraft landing and the corresponding experiment task. The correct rate and reaction time are chosen as the performance evaluation indexes, combined with eye movement data. The advantages and disadvantages of different information coding methods are also evaluated and analyzed. The experiment results demonstrate that the effect of color coding on the correct rate of information identification is not significant, but the effect on the speed of information identification is obviously significant. The study demonstrates that on a black background, red, green and yellow are suitable colors for color coding, but blue is not. The position of information on the performance of information identification is also significant. The center of the interface is better than the edge, and the left position is superior to the right. The impact of language and a person＇s mother tongue should also be considered in practical applications. The study shows that the Chinese has a higher correct rate of identification than English. As the experiment research method in the present study is based on flight simulator, the actual utility and application value can be guaranteed. The research results have the ability to offer improvements in ergonomic reference for cockpit human-machine interface design.展开更多
The growing number of mobile users, as well as the diversification in types of services have resulted in increasing demands for wireless network bandwidth in recent years. Although evolving transmission techniques are...The growing number of mobile users, as well as the diversification in types of services have resulted in increasing demands for wireless network bandwidth in recent years. Although evolving transmission techniques are able to enlarge the network capacity to some degree, they still cannot satisfy the requirements of mobile users. Meanwhile, following Moore's Law, the data processing capabilities of mobile user terminals are continuously improving. In this paper, we explore possible methods of trading strong computational power at wireless terminals for transmission efficiency of communications. Taking the specific scenario of wireless video conversation, we propose a model-based video coding scheme by learning the structures in multimedia contents. Benefiting from both strong computing capability and pre-learned model priors, only low-dimensional parameters need to be transmitted; and the intact multimedia contents can also be reconstructed at the receivers in real-time. Experiment results indicate that, compared to conventional video codecs, the proposed scheme significantly reduces the data rate with the aid of computational capability at wireless terminals.展开更多
A novel practical codebook-precoding multiple-input multiple-output（MIMO） system based on signal space diversity（SSD） with the minimum mean squared error（MMSE）receiver is proposed.This scheme utilizes rotation m...A novel practical codebook-precoding multiple-input multiple-output（MIMO） system based on signal space diversity（SSD） with the minimum mean squared error（MMSE）receiver is proposed.This scheme utilizes rotation modulation and space-time-frequency component interleaving.A novel precoding matrix selection criterion to maximize the average signal to interference plus noise ratio（SINR） is also put forward for the proposed scheme,which has a larger average mutual information（AMI）.Based on the AMI- maximization criterion,the optimal rotation angles for the proposed system are also investigated.The new scheme can make full use of space-time-frequency diversity and signal space diversity,and exhibit high spectral efficiency and high reliability in fading channels.Simulation results show that the proposed scheme greatly outperforms the conventional bit- interleaved coded modulation（BICM） MIMO-orthogonal frequency division multiplexing（OFDM） scheme without SSD,which is up to4.5 dB signal-to-noise ratio（SNR） gain.展开更多
Soft decode-and-forward(DF) can combine the advantages of both amplify-and-forward and hard DF in relay channels. In this paper, we propose a low-complexity soft DF scheme based on polar codes, which features two key ...Soft decode-and-forward(DF) can combine the advantages of both amplify-and-forward and hard DF in relay channels. In this paper, we propose a low-complexity soft DF scheme based on polar codes, which features two key techniques: a low-complexity cyclic redundancy check(CRC) aided list successive cancellation(CALSC) decoder and a soft information calculation method. At the relay node, a low-complexity CALSC decoder is designed to reduce the computational complexity by adjusting the list size according to the reliabilities of decoded bits. Based on the path probability metric of the CALSC decoder, we propose a method to compute the soft information of the decoded bits in CALSC. Simulation results show that our proposed scheme outperforms the soft DF based on low-density parity-check codes and the soft DF with belief propagation or soft cancellation decoder, especially in the case when the source-relay channel is at the high signal-to-ratio region.展开更多
The Q-ary low-density parity-check（LDPC） coded high order partial response continuous phase modulation（PR-CPM） with double iterative loops is investigated. This scheme shows significant improvements in power and b...The Q-ary low-density parity-check（LDPC） coded high order partial response continuous phase modulation（PR-CPM） with double iterative loops is investigated. This scheme shows significant improvements in power and bandwidth efficiency, but at the expense of long iterative decoding delay and computational complexity induced by the improper match between the demodulator and the decoder. To address this issue, the convergence behavior of Q-ary LDPC coded CPM is investigated for the Q=2 and Q〉2 cases, and an optimized design method based on the extrinsic information transfer chart is proposed to improve the systematic iterative efficiency. Simulation results demonstrate that the proposed method can achieve a perfect tradeoff between iterative decoding delay and bit error rate performance to satisfy real-time applications.展开更多
基金Projects supported by the Hi-Tech Research and Development Pro-gram (863) of China (No. 2004AA84ts03) and the Science and Technology Committee of Zhejiang Province (No. 2004C31018), China
文摘Information embodied in machine component classification codes has internal relation with the probability distribu- tion of the code symbol. This paper presents a model considering codes as information source based on Shannon’s information theory. Using information entropy, it preserves the mathematical form and quantitatively measures the information amount of a symbol and a bit in the machine component classification coding system. It also gets the maximum value of information amount and the corresponding coding scheme when the category of symbols is fixed. Samples are given to show how to evaluate the information amount of component codes and how to optimize a coding system.
基金supported by National Basic Research Program of China (973 Program, Grant No. 2010CB734104)
文摘Pilot needs to process lots of information when operating an aircraft, and reasonable information coding can greatly improve the correct rate and speed of information identification. At present, related researches are mainly performed in the laboratory, and the experiment method for abstract simulation is often used to research single digit information coding. The research results demonstrate a lack of systematization and applicability. The present study is based upon information coding methods of human-machine interface under real time in flight simulators. Subjects are required to perform an aircraft landing and the corresponding experiment task. The correct rate and reaction time are chosen as the performance evaluation indexes, combined with eye movement data. The advantages and disadvantages of different information coding methods are also evaluated and analyzed. The experiment results demonstrate that the effect of color coding on the correct rate of information identification is not significant, but the effect on the speed of information identification is obviously significant. The study demonstrates that on a black background, red, green and yellow are suitable colors for color coding, but blue is not. The position of information on the performance of information identification is also significant. The center of the interface is better than the edge, and the left position is superior to the right. The impact of language and a person＇s mother tongue should also be considered in practical applications. The study shows that the Chinese has a higher correct rate of identification than English. As the experiment research method in the present study is based on flight simulator, the actual utility and application value can be guaranteed. The research results have the ability to offer improvements in ergonomic reference for cockpit human-machine interface design.
基金supported by the National Basic Research Project of China (973) (2013CB329006)National Natural Science Foundation of China (NSFC, 61101071,61471220, 61021001)Tsinghua University Initiative Scientific Research Program
文摘The growing number of mobile users, as well as the diversification in types of services have resulted in increasing demands for wireless network bandwidth in recent years. Although evolving transmission techniques are able to enlarge the network capacity to some degree, they still cannot satisfy the requirements of mobile users. Meanwhile, following Moore's Law, the data processing capabilities of mobile user terminals are continuously improving. In this paper, we explore possible methods of trading strong computational power at wireless terminals for transmission efficiency of communications. Taking the specific scenario of wireless video conversation, we propose a model-based video coding scheme by learning the structures in multimedia contents. Benefiting from both strong computing capability and pre-learned model priors, only low-dimensional parameters need to be transmitted; and the intact multimedia contents can also be reconstructed at the receivers in real-time. Experiment results indicate that, compared to conventional video codecs, the proposed scheme significantly reduces the data rate with the aid of computational capability at wireless terminals.
基金supported by the National Natural Science Foundation of China(61171101)the Fundamental Research Funds for the Central Universitiesthe 2014 Doctorial Innovation Fund of Beijing University of Posts and Telecommunications(CX201426)
文摘A novel practical codebook-precoding multiple-input multiple-output（MIMO） system based on signal space diversity（SSD） with the minimum mean squared error（MMSE）receiver is proposed.This scheme utilizes rotation modulation and space-time-frequency component interleaving.A novel precoding matrix selection criterion to maximize the average signal to interference plus noise ratio（SINR） is also put forward for the proposed scheme,which has a larger average mutual information（AMI）.Based on the AMI- maximization criterion,the optimal rotation angles for the proposed system are also investigated.The new scheme can make full use of space-time-frequency diversity and signal space diversity,and exhibit high spectral efficiency and high reliability in fading channels.Simulation results show that the proposed scheme greatly outperforms the conventional bit- interleaved coded modulation（BICM） MIMO-orthogonal frequency division multiplexing（OFDM） scheme without SSD,which is up to4.5 dB signal-to-noise ratio（SNR） gain.
基金supported by the National Natural Science Foundation of China(No.61171099,No.61671080),Nokia Beijing Bell lab
文摘Soft decode-and-forward(DF) can combine the advantages of both amplify-and-forward and hard DF in relay channels. In this paper, we propose a low-complexity soft DF scheme based on polar codes, which features two key techniques: a low-complexity cyclic redundancy check(CRC) aided list successive cancellation(CALSC) decoder and a soft information calculation method. At the relay node, a low-complexity CALSC decoder is designed to reduce the computational complexity by adjusting the list size according to the reliabilities of decoded bits. Based on the path probability metric of the CALSC decoder, we propose a method to compute the soft information of the decoded bits in CALSC. Simulation results show that our proposed scheme outperforms the soft DF based on low-density parity-check codes and the soft DF with belief propagation or soft cancellation decoder, especially in the case when the source-relay channel is at the high signal-to-ratio region.
基金supported by the National Natural Science Foundation of China(61403093)the Science Foundation of Heilongjiang Province of China for Returned Scholars(LC2013C22)the Assisted Project by Heilongjiang Province of China Postdoctoral Funds for Scientific Research Initiation(LBH-Q14048)
文摘The Q-ary low-density parity-check（LDPC） coded high order partial response continuous phase modulation（PR-CPM） with double iterative loops is investigated. This scheme shows significant improvements in power and bandwidth efficiency, but at the expense of long iterative decoding delay and computational complexity induced by the improper match between the demodulator and the decoder. To address this issue, the convergence behavior of Q-ary LDPC coded CPM is investigated for the Q=2 and Q〉2 cases, and an optimized design method based on the extrinsic information transfer chart is proposed to improve the systematic iterative efficiency. Simulation results demonstrate that the proposed method can achieve a perfect tradeoff between iterative decoding delay and bit error rate performance to satisfy real-time applications.
