Due to high spectral efficiency and power efficiency, the continuous phase modulation(CPM) technique with constant envelop is widely used in range telemetry. How to improve the bit error rate(BER) performance of CPM a...Due to high spectral efficiency and power efficiency, the continuous phase modulation(CPM) technique with constant envelop is widely used in range telemetry. How to improve the bit error rate(BER) performance of CPM and keep a reasonable computational complexity is the key of the entire telemetry system and the focus of research and engineering design. In this paper, a reduced-state noncoherent maximum likelihood sequence detection(MLSD) method for CPM is proposed. In the proposed method, the criterion of noncoherent MLSD is derived for CPM when the carrier phase is unknown. A novel Viterbi algorithm(VA) with modified state vector is designed to simplify the implementation of noncoherent MLSD. Both analysis and numerical results show that the proposed method reduces the computational complexity significantly and does not need accurate carrier phase recovery, which overcomes the shortage of traditional MLSD method. Additionally, the proposed method exceeds the traditional MLSD method when carrier phase deviation exists.展开更多
In this paper, a detection strategy based on a semidefinite relaxation of the CDMA maximum-likelihoodmultiuser detection is investigated. Coordinate descent algorithm is used to strengthen the approximation. The simu-...In this paper, a detection strategy based on a semidefinite relaxation of the CDMA maximum-likelihoodmultiuser detection is investigated. Coordinate descent algorithm is used to strengthen the approximation. The simu-lated bit-error-rate performance demonstrates that this approach provides a good approximation to the maximum-like-lihood multiuser detection.展开更多
提出了新的基于离散傅立叶变换(DFT)的重叠频分复用(Overlapped Frequency Division Multiplexing-OvFDM)或非正交频分复用(Non-orthogonal Frequency Division Multiplexing-NOFDM)系统。该系统利用相互重叠的子载波对所发送的数据符...提出了新的基于离散傅立叶变换(DFT)的重叠频分复用(Overlapped Frequency Division Multiplexing-OvFDM)或非正交频分复用(Non-orthogonal Frequency Division Multiplexing-NOFDM)系统。该系统利用相互重叠的子载波对所发送的数据符号序列进行调制,形成复调制信号,接收端采用最大似然序列检测。该系统的频谱效率与重叠重数成正比,可以大幅度的提高频谱效率;并且该系统子载波带宽大于信道相关带宽,系统在随机时变信道中会自动产生隐分集增益,因此具有较强的抗衰落能力。展开更多
Overlapped X domain multiplexing(Ov XDM) is a promising encoding technique to obtain high spectral efficiency by utilizing Inter-Symbol Interference(ISI). However, the computational complexity of Maximum Likelihood Se...Overlapped X domain multiplexing(Ov XDM) is a promising encoding technique to obtain high spectral efficiency by utilizing Inter-Symbol Interference(ISI). However, the computational complexity of Maximum Likelihood Sequence Detection(MLSD) increases exponentially with the growth of spectral efficiency in Ov XDM, which is unbearable for practical implementations. This paper proposes an Ov TDM decoding method based on Recurrent Neural Network(RNN) to realize fast decoding of Ov TDM system, which has lower decoding complexity than the traditional fast decoding method. The paper derives the mathematical model of the Ov TDM decoder based on RNN and constructs the decoder model. And we compare the performance of the proposed decoding method with the MLSD algorithm and the Fano algorithm. It’s verified that the proposed decoding method exhibits a higher performance than the traditional fast decoding algorithm, especially for the scenarios of a high overlapped multiplexing coefficient.展开更多
The continuous phase modulation(CPM)technique is widely used in range telemetry due to its high spectral efficiency and power efficiency.However,the demodulation performance of the traditional maximum likelihood seque...The continuous phase modulation(CPM)technique is widely used in range telemetry due to its high spectral efficiency and power efficiency.However,the demodulation performance of the traditional maximum likelihood sequence detection(MLSD)algorithm significantly deteriorates in non-ideal synchronization or fading channels.To address this issue,this work proposes a convolutional neural network(CNN)called the cascade parallel crossing network(CPCNet)to enhance the robustness of CPM signals demodulation.The CPCNet model employs a multiple parallel structure and feature fusion to extract richer features from CPM signals.This approach constructs feature maps at different levels,resulting in a more comprehensive training of the model and improved demodulation performance.Simulation results show that under Gaussian channel,the proposed CPCNet achieves the same bit error rate(BER)performance as MLSD method when there is no timing error,but with 1/4 symbol period timing error,the proposed method has 2 dB demodulation gain compared with CNN and convolutional long short-term memory deep neural network(CLDNN).In addition,under Rayleigh channel,the BER of the proposed method is reduced by 5%-87%compared to that of MLSD in the wide signal-to-noise ratio(SNR)region.展开更多
According to the analysis of meteor burst communication (MBC) mechanism, a model of signal processing based on the structure of data frame is suggested for adaptive modulation and coding (AMC) of MBC system in this pa...According to the analysis of meteor burst communication (MBC) mechanism, a model of signal processing based on the structure of data frame is suggested for adaptive modulation and coding (AMC) of MBC system in this paper. There are two distinct modes of operation for signal processing: acquisition and tracking. The acquisition mode is a training period to initialize the channel estimation by frame header. The tracking mode is jointly to equalize payload data and to trace channel, where the principle of per-survivor processing (PSP) for maximum likelihood sequence detection (MLSD) is performed. A suboptimal method called D-PSP is adopted to save the computational time and memory size, which agrees with the slow-fading characteristic of meteor channel and makes the MLSD possible for adaptive modulation and coding of MBC system. Computer simulation results are included to support our development.展开更多
基金supported by the Fundamental Research Funds for the Central Universities ( BLX201623 )the National Natural Science Foundation of China ( 31700479)。
文摘Due to high spectral efficiency and power efficiency, the continuous phase modulation(CPM) technique with constant envelop is widely used in range telemetry. How to improve the bit error rate(BER) performance of CPM and keep a reasonable computational complexity is the key of the entire telemetry system and the focus of research and engineering design. In this paper, a reduced-state noncoherent maximum likelihood sequence detection(MLSD) method for CPM is proposed. In the proposed method, the criterion of noncoherent MLSD is derived for CPM when the carrier phase is unknown. A novel Viterbi algorithm(VA) with modified state vector is designed to simplify the implementation of noncoherent MLSD. Both analysis and numerical results show that the proposed method reduces the computational complexity significantly and does not need accurate carrier phase recovery, which overcomes the shortage of traditional MLSD method. Additionally, the proposed method exceeds the traditional MLSD method when carrier phase deviation exists.
文摘In this paper, a detection strategy based on a semidefinite relaxation of the CDMA maximum-likelihoodmultiuser detection is investigated. Coordinate descent algorithm is used to strengthen the approximation. The simu-lated bit-error-rate performance demonstrates that this approach provides a good approximation to the maximum-like-lihood multiuser detection.
文摘提出了新的基于离散傅立叶变换(DFT)的重叠频分复用(Overlapped Frequency Division Multiplexing-OvFDM)或非正交频分复用(Non-orthogonal Frequency Division Multiplexing-NOFDM)系统。该系统利用相互重叠的子载波对所发送的数据符号序列进行调制,形成复调制信号,接收端采用最大似然序列检测。该系统的频谱效率与重叠重数成正比,可以大幅度的提高频谱效率;并且该系统子载波带宽大于信道相关带宽,系统在随机时变信道中会自动产生隐分集增益,因此具有较强的抗衰落能力。
基金supported by the National Natural Science Foundation of China under Grant No.61871049.
文摘Overlapped X domain multiplexing(Ov XDM) is a promising encoding technique to obtain high spectral efficiency by utilizing Inter-Symbol Interference(ISI). However, the computational complexity of Maximum Likelihood Sequence Detection(MLSD) increases exponentially with the growth of spectral efficiency in Ov XDM, which is unbearable for practical implementations. This paper proposes an Ov TDM decoding method based on Recurrent Neural Network(RNN) to realize fast decoding of Ov TDM system, which has lower decoding complexity than the traditional fast decoding method. The paper derives the mathematical model of the Ov TDM decoder based on RNN and constructs the decoder model. And we compare the performance of the proposed decoding method with the MLSD algorithm and the Fano algorithm. It’s verified that the proposed decoding method exhibits a higher performance than the traditional fast decoding algorithm, especially for the scenarios of a high overlapped multiplexing coefficient.
基金Supported by the Beijing Natural Science Foundation (L202003)。
文摘The continuous phase modulation(CPM)technique is widely used in range telemetry due to its high spectral efficiency and power efficiency.However,the demodulation performance of the traditional maximum likelihood sequence detection(MLSD)algorithm significantly deteriorates in non-ideal synchronization or fading channels.To address this issue,this work proposes a convolutional neural network(CNN)called the cascade parallel crossing network(CPCNet)to enhance the robustness of CPM signals demodulation.The CPCNet model employs a multiple parallel structure and feature fusion to extract richer features from CPM signals.This approach constructs feature maps at different levels,resulting in a more comprehensive training of the model and improved demodulation performance.Simulation results show that under Gaussian channel,the proposed CPCNet achieves the same bit error rate(BER)performance as MLSD method when there is no timing error,but with 1/4 symbol period timing error,the proposed method has 2 dB demodulation gain compared with CNN and convolutional long short-term memory deep neural network(CLDNN).In addition,under Rayleigh channel,the BER of the proposed method is reduced by 5%-87%compared to that of MLSD in the wide signal-to-noise ratio(SNR)region.
文摘According to the analysis of meteor burst communication (MBC) mechanism, a model of signal processing based on the structure of data frame is suggested for adaptive modulation and coding (AMC) of MBC system in this paper. There are two distinct modes of operation for signal processing: acquisition and tracking. The acquisition mode is a training period to initialize the channel estimation by frame header. The tracking mode is jointly to equalize payload data and to trace channel, where the principle of per-survivor processing (PSP) for maximum likelihood sequence detection (MLSD) is performed. A suboptimal method called D-PSP is adopted to save the computational time and memory size, which agrees with the slow-fading characteristic of meteor channel and makes the MLSD possible for adaptive modulation and coding of MBC system. Computer simulation results are included to support our development.
