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CN-122027398-A - Method, device and system for transmitting and receiving channel estimation of enhanced transform domain modulation system

CN122027398ACN 122027398 ACN122027398 ACN 122027398ACN-122027398-A

Abstract

The invention provides a transmitting and receiving method, a device and a system for enhancing channel estimation of a transform domain modulation system, wherein the transmitting method comprises the steps of generating constellation modulation symbols based on input information bits; generating a time domain OTFS modulation symbol based on a constellation modulation symbol, generating a time domain expansion OTFS modulation symbol based on the time domain OTFS modulation symbol, generating a basic pilot frequency symbol sequence, adding a zero suffix at the tail part of the basic pilot frequency symbol sequence, generating a time domain wireless baseband frame signal based on the time domain expansion OTFS modulation symbol and the time domain pilot frequency symbol sequence, performing up-sampling filtering on the time domain wireless baseband frame signal to generate a digital baseband signal, generating a radio frequency signal based on the digital baseband signal, and transmitting the radio frequency signal. The method, the device and the system for transmitting and receiving the enhanced transform domain modulation system channel estimation can realize accurate channel estimation with low peak-to-average ratio and low pilot frequency overhead under the environment of high Doppler expansion and long time delay expansion.

Inventors

  • LI MINGQI
  • YANG LANG
  • BIAN XIN
  • XING LIUJI
  • GUO RUIXUAN
  • XU CHUNLING
  • ZHANG JIALU

Assignees

  • 中国科学院上海高等研究院

Dates

Publication Date
20260512
Application Date
20241111

Claims (16)

  1. 1. A method of transmitting enhanced channel estimation in a transform domain modulation system, the method comprising the steps of: generating constellation modulation symbols based on the input information bits; Generating a time domain OTFS modulation symbol based on the constellation modulation symbol; Adding zero suffix at the tail of the time delay dimension symbol of the time domain OTFS modulation symbol to generate a time domain expansion OTFS modulation symbol; generating a basic pilot symbol sequence; adding zero suffix at the tail of the basic pilot frequency symbol sequence to generate a time domain pilot frequency symbol sequence; generating a time domain wireless baseband frame signal based on the time domain spread OTFS modulation symbol and the time domain pilot symbol sequence; Up-sampling filtering the time domain wireless baseband frame signal to generate a digital baseband signal; And generating a radio frequency signal based on the digital baseband signal and transmitting the radio frequency signal.
  2. 2. The method for transmitting enhanced transform domain modulation system channel estimation according to claim 1, wherein generating constellation modulation symbols based on the input information bits comprises the steps of: constellation modulation is carried out on the information bits { b 1 ,b 2 ,...,b MN×Q } based on a preset constellation mode and a modulation order Q; the constellation modulated information bits are serial-parallel converted to generate constellation modulation symbols { d 1 ,d 2 ,...,d N } of size m×n, where d i represents a constellation modulation symbol column vector of size M, i=1.
  3. 3. The method for transmitting channel estimates for an enhanced transform domain modulation system of claim 1 wherein generating time domain OTFS modulation symbols based on the constellation modulation symbols comprises the steps of: Inputting constellation modulation symbols { d 1 ,d 2 ,...,d N } with the size of m×n into a delay-doppler domain, respectively performing IDFT of N points on each constellation modulation symbol row vector with the size of N in a doppler dimension, and generating a delay time domain symbol S DT ＝{s 1 ,s 2 ,...,s N with the size of m×n, wherein the length of each delay dimension symbol S i is M, i=1, &..n; And sequentially and serially outputting N delay dimension symbols S i with the length of M in the delay time domain symbols along a time domain dimension to generate a time domain OTFS modulation symbol S= { S 1 ;s 2 ;...;s N } with the size of MN multiplied by 1.
  4. 4. The method for transmitting channel estimation of an enhanced transform domain modulation system according to claim 1, wherein adding a zero suffix at the tail of each time delay dimension symbol of said time domain OTFS modulation symbols, generating a time domain spread OTFS modulation symbol comprises the steps of: The tail part of each time delay dimension symbol S i in the time domain OTFS modulation symbol S= { S 1 ;s 2 ;...;s N } with the size of MN x 1 is respectively added with a 0 symbol sequence Z= {0 with the size of H x 1; 0, generating a time domain spread OTFS modulation symbol S EX ＝{s 1 Z;s 2 Z;...;s N Z of size (m+h) N x 1, where S i Z represents an spread delay dimension symbol of size (m+h) x 1, i=1, N, H is not less than the length of the channel impulse response and is less than M.
  5. 5. The method for transmitting channel estimation in an enhanced transform domain modulation system according to claim 1, wherein the basic pilot symbol sequence is generated by OFDM modulation using or from a CAZAC sequence, a PN sequence, or a barker code sequence.
  6. 6. The method for transmitting channel estimates of an enhanced transform domain modulation system of claim 1 wherein adding a zero suffix to the tail of said basic pilot symbol sequence, generating a time domain pilot symbol sequence comprises the steps of: adding a 0 symbol sequence Z= { 0;..0 }. With a size of H x1 to the tail of the basic pilot symbol sequence P0= { a 0 ;a 1 ;...;a L-1 } to form a time domain pilot symbol sequence P with a size of (L+H) x1, P={P0;Z}={a 0 ;a 1 ;...;a L-1 ;0;...;0}。
  7. 7. The method for transmitting channel estimation of an enhanced transform domain modulation system according to claim 1, wherein generating a time domain wireless baseband frame signal based on the time domain spread OTFS modulation symbol and the time domain pilot symbol sequence comprises the steps of: A time domain pilot frequency symbol sequence P is respectively added at the tail part of each extended time delay dimension symbol S i Z of the time domain extended OTFS modulation symbol S EX ＝{s 1 Z;s 2 Z;...;s N Z with the size of (M+H) N multiplied by 1; A time domain pilot symbol sequence P is added to the header of s 1 Z, and a time domain wireless baseband frame signal S F ＝{P 0 ;s 1 Z;P 1 ;s 2 Z;P 2 ;...;s N Z;P N },P p with a size of [ (n+1) (l+h) +n (m+h) ] x 1 is generated in a cascading manner, where p=0 and N.
  8. 8. The device comprises a constellation modulation module, a time domain OTFS modulation symbol generation module, a zero suffix adding module, a basic pilot symbol sequence generation module, a time domain wireless baseband frame signal generation module, a filtering module and a radio frequency transmission module; The constellation modulation module is used for generating constellation modulation symbols based on input information bits; the time domain OTFS modulation symbol generation module is configured to generate a time domain OTFS modulation symbol based on the constellation modulation symbol; The zero suffix adding module is used for adding zero suffixes at the tail part of each time delay dimension symbol of the time domain OTFS modulation symbol to generate a time domain expansion OTFS modulation symbol; The basic pilot frequency symbol sequence generation module is used for generating a basic pilot frequency symbol sequence; the time domain pilot frequency symbol sequence generating module is used for adding zero suffix at the tail part of the basic pilot frequency symbol sequence to generate a time domain pilot frequency symbol sequence; the time domain wireless baseband frame signal generating module is used for generating a time domain wireless baseband frame signal based on the time domain spread OTFS modulation symbol and the time domain pilot frequency symbol sequence; the filtering module is used for carrying out up-sampling filtering on the time domain wireless baseband frame signal to generate a digital baseband signal, and the radio frequency transmitting module is used for generating a radio frequency signal based on the digital baseband signal and transmitting the radio frequency signal.
  9. 9. A method of receiving an enhanced transform domain modulation system channel estimate, the method comprising the steps of: receiving a radio frequency signal and generating a digital received signal based on the radio frequency signal; Performing downsampling filtering on the digital receiving signal to generate a digital receiving baseband signal; Extracting pilot symbol sequences received in all pilot symbol intervals in a wireless baseband frame based on the digital received baseband signal; Performing channel estimation of a pilot frequency interval based on the pilot frequency symbol sequence, and acquiring channel impulse response of each pilot frequency symbol interval estimation; performing time domain dimension interpolation on the channel impulse response to generate channel fading coefficients of all the extended time delay dimension symbols in the wireless baseband frame; extracting all received extended delay dimension symbols in a wireless baseband frame based on the digital received baseband signal; demodulating the extended delay dimension symbol based on the channel fading coefficient to generate an estimated value of a constellation modulation symbol; And performing constellation demodulation on the estimated value of the constellation modulation symbol to generate received information bits.
  10. 10. The method for receiving channel estimates for an enhanced transform domain modulation system of claim 9 wherein performing channel estimation for pilot intervals based on said pilot symbol sequence and obtaining channel impulse responses for each pilot symbol interval estimate comprises the steps of: Performing L+H point discrete Fourier transform on the time domain pilot symbol sequence P p to generate a frequency domain symbol P=0..a., N, L represents the length of the basic pilot symbol sequence corresponding to the time domain pilot symbol sequence, H represents the length of the 0 symbol sequence added at the tail of the basic pilot symbol sequence, N represents the number of extended delay dimension symbols in the wireless baseband frame, and n+1 is the number of the time domain pilot symbol sequences; Performing L+H point discrete Fourier transform on pilot symbol sequences rP p received in the pilot symbol interval to generate frequency domain symbols Calculating the frequency response of the pilot symbol interval Wherein/represents a vector division operation; Performing L+H point discrete Fourier inverse transformation on the frequency response to generate an initial estimated channel impulse response The elements of which are expressed as n=0,...,L+H-1; And acquiring the estimated channel impulse response of each pilot frequency symbol interval according to the initially estimated channel impulse response based on an effective path energy threshold value or the number of effective paths.
  11. 11. The method for receiving channel estimation of enhanced transform domain modulation system according to claim 10, wherein N=0..h-1 obtains the channel impulse response of each pilot symbol interval estimate Wherein Thr1 represents the effective path energy threshold.
  12. 12. The method for receiving channel estimation of enhanced transform domain modulation system according to claim 9, wherein the method comprises the steps of N=0..h-1 obtains the channel impulse response of each pilot symbol interval estimate Wherein Ω is N=0..a.a set of sequence numbers corresponding to the N p values with the largest energy in H-1, N p represents the number of effective paths.
  13. 13. The method for receiving channel estimates for an enhanced transform domain modulation system of claim 9 wherein performing channel estimation for pilot intervals based on said pilot symbol sequence and obtaining channel impulse responses for each pilot symbol interval estimate comprises the steps of: Performing normalized autocorrelation operation on the time domain pilot symbol sequence Pp to generate a normalized autocorrelation value xP p (N), wherein p=0,..n, n= -L,..0,..l, L represents the length of the basic pilot symbol sequence corresponding to the time domain pilot symbol sequence; N represents the number of the extended time delay dimension symbols in the wireless baseband frame, and N+1 represents the number of the time domain pilot frequency symbol sequences; Performing cross-correlation operation on the pilot symbol sequence rP p and the time domain pilot symbol sequence P p respectively to generate a cross-correlation value c p (n); Selecting Np values of the cross-correlation values c p (n) with the largest energy, where Np represents the number of effective paths; performing self-interference cancellation on the selected cross-correlation value based on the normalized autocorrelation value; Cross correlation value for eliminating self-interference Performing time domain noise reduction to obtain channel impulse response of each pilot frequency symbol interval estimation Where k=1..n p ,n＝0,...,H-1,Ind p (k) is the sequence number of the N p values of maximum energy in the estimated channel impulse response.
  14. 14. The method for receiving channel estimates for an enhanced transform domain modulation system of claim 9 wherein constellation demodulating the estimated values of the constellation modulation symbols to generate received information bits comprises the steps of: performing constellation demodulation on the estimated value of the constellation modulation symbol according to the constellation mode and the modulation order; and carrying out parallel-to-serial conversion on the estimated value after constellation demodulation to generate the received information bit.
  15. 15. The receiving device for enhancing the channel estimation of the transform domain modulation system is characterized by comprising a radio frequency receiving module, a filtering module, a pilot frequency symbol sequence extracting module, a channel impulse response estimating module, an interpolation module, a data symbol extracting module, a channel balancing module and a constellation demodulating module; the radio frequency receiving module is used for receiving radio frequency signals and generating digital receiving signals based on the radio frequency signals; the filtering module is used for carrying out downsampling filtering on the digital receiving signal to generate a digital receiving baseband signal; the pilot symbol sequence extraction module is used for extracting pilot symbol sequences received by all pilot symbol intervals in a wireless baseband frame based on the digital receiving baseband signal; The channel impulse response estimation module is used for carrying out channel estimation of a pilot frequency interval based on the pilot frequency symbol sequence, and obtaining channel impulse response estimated by each pilot frequency symbol interval; The interpolation module is used for carrying out time domain dimension interpolation on the channel impulse response to generate channel fading coefficients of all the expansion data symbols in the wireless baseband frame; the data symbol extraction module is used for extracting all received spread data symbols in a wireless baseband frame based on the digital received baseband signal; The channel equalization module is used for demodulating the extended delay dimension symbol based on the channel fading coefficient to generate an estimated value of a constellation modulation symbol; The constellation demodulation module is used for constellation demodulation of the estimated value of the constellation modulation symbol to generate received information bits.
  16. 16. An enhanced transform domain modulation system channel estimation system comprising the transmission apparatus of the enhanced transform domain modulation system channel estimation of claim 8 and the reception apparatus of the enhanced transform domain modulation system channel estimation of claim 15.

Description

Method, device and system for transmitting and receiving channel estimation of enhanced transform domain modulation system Technical Field The present invention relates to the field of mobile communications technologies, and in particular, to a method, an apparatus, and a system for transmitting and receiving channel estimation of an enhanced transform domain modulation system. Background With the rapid development of applications such as unmanned aerial vehicles, internet of vehicles, low-orbit satellites, and the like, wireless communication oriented to high-speed mobile devices is receiving more and more attention from the industry and academia. Because the moving scene has the characteristics of high moving speed and wide transmission distance, space-to-air, space-to-ground and ground communication in the scene faces serious time-frequency double-selection fading characteristics. Conventional orthogonal frequency division multiplexing (Orthogonal Frequency Division Multiplexing, OFDM) transmission techniques based on time-frequency domain modulation have difficulty in coping with wireless channels having both long delay spread and high doppler shift. In recent years, based on the transform domain of the time-frequency domain, the orthogonal time-frequency space multiplexing (Orthogonal Time Frequency Space, OTFS) transmission technology of the delay-doppler domain modulation has become one of the potential solutions of future mobile communication increasingly due to the good time-frequency dual-selection fading channel characteristic. Unlike OFDM techniques, OTFS performs resource mapping in the Delay Doppler (DD) domain, and can achieve higher reliability of data transmission compared to OFDM under high-speed moving conditions based on sparsity and stability of DD domain channels. In addition, for the zero suffix OTFS system, the iterative Rake decision feedback equalization and other detection algorithms are adopted, so that the demodulation complexity of the OTFS signal can be effectively reduced on the premise of ensuring the detection performance. To achieve reliable detection of OTFS signals, efficient estimation of the time-frequency bi-selected channel experienced by the OTFS signal is required. The traditional single-point pulse pilot frequency design based on power enhancement can lead the power of a pilot signal to be ten or more dB higher than that of a data signal, so that the peak-to-average ratio (Peak to Average Power Ratio, PAPR) of an OTFS time domain waveform is remarkably improved, and great challenges are brought to the power amplification efficiency of a transmitter. If in the delay-doppler domain, a doppler component is selected and pilots are deployed along the delay direction, although the PAPR of the OTFS time domain can be effectively reduced. However, if the distributed pilot frequency occupies the whole delay dimension, the overhead of the pilot frequency is obviously increased, and the mutual interference between the pilot frequency and the data is also caused, so that the performance of channel estimation is affected. Disclosure of Invention In view of the above drawbacks of the prior art, an object of the present invention is to provide a method, an apparatus and a system for transmitting and receiving channel estimation of an enhanced transform domain modulation system, which can realize accurate channel estimation with low peak-to-average ratio and low pilot overhead under the environment of high doppler spread and long delay spread. In a first aspect, the invention provides a method for transmitting channel estimation of an enhanced transform domain modulation system, which comprises the steps of generating constellation modulation symbols based on input information bits, generating time domain OTFS modulation symbols based on the constellation modulation symbols, adding zero suffixes at the tail parts of time delay dimension symbols of the time domain OTFS modulation symbols, generating time domain expansion OTFS modulation symbols, generating a basic pilot frequency symbol sequence, adding zero suffixes at the tail parts of the basic pilot frequency symbol sequence, generating a time domain wireless baseband frame signal based on the time domain expansion OTFS modulation symbols and the time domain pilot frequency symbol sequence, carrying out up-sampling filtering on the time domain wireless baseband frame signal, generating a digital baseband signal, generating a radio frequency signal based on the digital baseband signal, and transmitting the radio frequency signal. In one implementation of the first aspect, generating constellation modulation symbols based on the input information bits comprises the steps of: constellation modulation is carried out on the information bits { b 1,b2,...,bMN×Q } based on a preset constellation mode and a modulation order Q; the constellation modulated information bits are serial-parallel converted to generate constellation modulatio