To solve the inter carrier interference (ICI) elimination problem of an M-band wavelet multi-carrier modulation system, this paper analyzes the principle of the ICI caused by the Doppler frequency shift and its math...To solve the inter carrier interference (ICI) elimination problem of an M-band wavelet multi-carrier modulation system, this paper analyzes the principle of the ICI caused by the Doppler frequency shift and its mathematical expression based on the M-band wavelet multi-carrier modulation system model. Through the analysis of the mathematical expression and combining with the perfect reconstruction conditions of the filter banks, we propose the design conditions of an M-band filter to reduce and eliminate the ICI. The impulse response model of the filter design conditions and an iterative algorithm is also established. The simulation results show that the proposed ICI reduction and elimination methods can effectively improve the system performance.展开更多
With the development of High-Speed Rail(HSR),countries and individual passengers alike have enjoyed far ranging benefits as a result-economic,social,environment and in added convenience.One of the important parts of H...With the development of High-Speed Rail(HSR),countries and individual passengers alike have enjoyed far ranging benefits as a result-economic,social,environment and in added convenience.One of the important parts of HSR construction is the signaling system,where wireless communications play a key role in the transmission of train control data.Channel estimation has a significant impact on the quality of the wireless communication,however,whose performance is degraded due to the fast mobility of HSR.This paper focuses on the channel estimation technology in HSR.We first summarize the key challenges for HSR channel estimation,especially the Inter-Carrier Interference(ICI)faced by Orthogonal Frequency Division Multiplexing(OFDM)systems.Then we provide a comprehensive review of existing pilot-aided channel estimation schemes from three points:channel model,estimation algorithm,joint channel estimation and ICI mitigation schemes.Lastly,we present the challenges of channel estimation for the Orthogonal Time Frequency Space(OTFS)system and Reconfigurable Intelligent Surface(RIS),which are promising techniques for HSR systems in the future sixth Generation(6G)wireless communication.展开更多
Orthogonal frequency division multiplexing (OFDM), a very promising technique that is leading the evolution in wireless mobile communication to sideline the bandwidth scarcity issue in spectrum allocation, is severe...Orthogonal frequency division multiplexing (OFDM), a very promising technique that is leading the evolution in wireless mobile communication to sideline the bandwidth scarcity issue in spectrum allocation, is severely affected by the undesirable effects of the frequency offset error, which generates inter cartier interference (ICI) due to the Doppler shift and local oscillator frequency synchronization errors. There are many ICI cancellation techniques available in the literature, such as self-cancellation (SC), maximum likelihood estimation (MLE), and windowing, but they present a tradeoff between bandwidth redundancy and system complexity. In this study, a new energy-efficient, bandwidth-effective technique is proposed to mitigate ICI through cyclic prefix (CP) reuse at the receiver end. Unlike SC and MLE where the whole OFDM symbol data is transmitted in duplicate to create redundancy at the transmitter end, the proposed technique uses the CP data (which is only 20% of the total symbol bandwidth) to estimate the channel, and it produces similar results with a huge bandwidth saving. The simulation results show that the proposed technique has a significant improvement in error performance, and a comparative analysis demonstrates the substantial improvement in energy efficiency with high bandwidth gain. Therefore, it outperforms the legacy IC1 cancellation schemes under consideration.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.60872114)
文摘To solve the inter carrier interference (ICI) elimination problem of an M-band wavelet multi-carrier modulation system, this paper analyzes the principle of the ICI caused by the Doppler frequency shift and its mathematical expression based on the M-band wavelet multi-carrier modulation system model. Through the analysis of the mathematical expression and combining with the perfect reconstruction conditions of the filter banks, we propose the design conditions of an M-band filter to reduce and eliminate the ICI. The impulse response model of the filter design conditions and an iterative algorithm is also established. The simulation results show that the proposed ICI reduction and elimination methods can effectively improve the system performance.
文摘With the development of High-Speed Rail(HSR),countries and individual passengers alike have enjoyed far ranging benefits as a result-economic,social,environment and in added convenience.One of the important parts of HSR construction is the signaling system,where wireless communications play a key role in the transmission of train control data.Channel estimation has a significant impact on the quality of the wireless communication,however,whose performance is degraded due to the fast mobility of HSR.This paper focuses on the channel estimation technology in HSR.We first summarize the key challenges for HSR channel estimation,especially the Inter-Carrier Interference(ICI)faced by Orthogonal Frequency Division Multiplexing(OFDM)systems.Then we provide a comprehensive review of existing pilot-aided channel estimation schemes from three points:channel model,estimation algorithm,joint channel estimation and ICI mitigation schemes.Lastly,we present the challenges of channel estimation for the Orthogonal Time Frequency Space(OTFS)system and Reconfigurable Intelligent Surface(RIS),which are promising techniques for HSR systems in the future sixth Generation(6G)wireless communication.
文摘Orthogonal frequency division multiplexing (OFDM), a very promising technique that is leading the evolution in wireless mobile communication to sideline the bandwidth scarcity issue in spectrum allocation, is severely affected by the undesirable effects of the frequency offset error, which generates inter cartier interference (ICI) due to the Doppler shift and local oscillator frequency synchronization errors. There are many ICI cancellation techniques available in the literature, such as self-cancellation (SC), maximum likelihood estimation (MLE), and windowing, but they present a tradeoff between bandwidth redundancy and system complexity. In this study, a new energy-efficient, bandwidth-effective technique is proposed to mitigate ICI through cyclic prefix (CP) reuse at the receiver end. Unlike SC and MLE where the whole OFDM symbol data is transmitted in duplicate to create redundancy at the transmitter end, the proposed technique uses the CP data (which is only 20% of the total symbol bandwidth) to estimate the channel, and it produces similar results with a huge bandwidth saving. The simulation results show that the proposed technique has a significant improvement in error performance, and a comparative analysis demonstrates the substantial improvement in energy efficiency with high bandwidth gain. Therefore, it outperforms the legacy IC1 cancellation schemes under consideration.