Self-adaptive joint channel estimation method and device based on time diversity technology

Abstract

The invention discloses an adaptive joint channel estimation method and device based on a time diversity technology, and the method comprises the steps: carrying out the down-sampling and OFDM demodulation of receiving data, obtaining the frequency domain data of a TB block of a binding time slot, and extracting a first receiving demodulation reference signal of each OFDM symbol in each time slot in the TB block of the binding time slot from the frequency domain data; generating a known sending demodulation reference signal of each OFDM symbol in each time slot in the TB blocks bound with the time slots; according to the frequency domain data, the first receiving demodulation reference signal and a known sending demodulation reference signal, carrying out adaptive joint channel estimation on each partial time slot block in the TB blocks bound with the time slots to obtain estimated sending data of each time slot in the partial time slot blocks; and splicing and decoding the estimated sending data of each time slot in all the partial time slot blocks to obtain sending information of the TB blocks bound with the time slots. The method is adaptive to a flexible time slot system, and joint channel estimation among part of time slots improves the channel estimation precision.

Description

Technical Field

[0001] This invention belongs to the field of satellite communication technology, specifically relating to an adaptive joint channel estimation method and apparatus based on time diversity technology. Background Technology

[0002] Low-Earth orbit (LEO) satellites, with their unique advantages of low latency, high bandwidth, and wide coverage, are playing an increasingly important role in areas where terrestrial communication networks have natural blind spots and in emerging application scenarios (low-altitude economy, ocean communication, emergency rescue and disaster relief, wide-area IoT connectivity, etc.). However, the longer distance between LEO satellites and the ground results in greater propagation loss compared to terrestrial communication. In addition, the relative velocity between LEO satellites and terminals is not zero, and the faster this relative velocity, the greater the Doppler frequency offset effect, which has a greater impact on the demodulation performance of data channels such as PUSCH (Physical Uplink Shared Channel).

[0003] To improve the coverage of low-Earth orbit satellite communications, the core idea of ​​existing technologies is to bind multiple time slots of PUSCH into a single TB (Transport Block) for retransmission at higher layers. One transport block is defined as one TB. Each time slot supports different numbers of OFDM (Orthogonal Frequency Division Multiplexing) symbols depending on the cyclic prefix mode. For example, a conventional cyclic prefix supports 14 OFDM symbols, while an extended cyclic prefix supports 12 OFDM symbols. Increasing the maximum number of retransmissions (e.g., 8 / 16 / 32 times) enhances the reliability of high-speed mobile communication under low signal-to-noise ratio conditions. The transmission mechanism is as follows: Figure 1 As shown.

[0004] Existing technology patent CN1177423C discloses a channel estimation method adapted to high-speed mobile conditions. Its main steps include: 1) The transmitting end allocates a single user's data to multiple (i.e., two or more) time slots within a frame, where these multiple time slots are temporally adjacent and continuous; 2) The receiving end performs channel estimation on the pilot signals of each of these multiple time slots, and interpolates the channel estimates of the data portion using the channel estimates of the pilot signals from adjacent time slots. It is evident that patent CN1177423C performs channel estimation on the pilot signals of each of these multiple time slots at the receiving end, and interpolates the channel estimates of the data portion using the channel estimates of the pilot signals from adjacent time slots to jointly calculate the channel estimate. This scheme is used in TD-CDMA (Time Division - Code Division Multiple Access) systems and requires these multiple time slots to be temporally continuous. However, time slot scheduling in low-Earth orbit satellite communication systems is very flexible, potentially involving a single time slot, multiple temporally continuous time slots, or multiple temporally discontinuous time slots. In scenarios with discontinuous time slots, the pilot interpolation scheme used in this patent is not feasible for recovering data channel estimation. This is because, under low signal-to-noise ratio (SNR) and large Doppler frequency offset, the channel time-varying nature is rapid, and the interpolation cannot track these changes, leading to a sharp degradation in performance. Furthermore, the limited accuracy of the channel estimates obtained from pilot estimation under low SNR also affects the accuracy of the joint channel estimation.

[0005] The prior art patent CN120151140A discloses a joint channel estimation and equalization method for OFDM systems under fast time-varying channels. Its main steps include: 1) performing channel estimation using frequency domain pilots; 2) eliminating the ICI (Inter-Carrier Interference) effects of other taps besides the current tap from the received signal for one tap in the channel impulse response; 3) updating the current tap and the entire channel response; 4) calculating and updating the ICI component of the current tap; 5) repeating steps 2) to 4) for other taps in the channel impulse response to update and obtain the final ICI vector, which is composed of the ICI components of each tap; 6) eliminating the ICI effects of all taps based on the final ICI vector; 7) performing channel estimation again using pilots based on the data after eliminating ICI and executing steps 2) to 7) until a set number of iterations is reached. As can be seen, patent CN120151140A solves the channel estimation problem in high-speed mobile states by eliminating the channel estimation taps calculated from the pilot through multiple iterations until a specified maximum number of iterations is reached. This method improves the accuracy of frequency offset estimation through multiple iterations of channel estimation; however, each iteration requires IS (Interference Signal) estimation and ICI elimination. ICI elimination typically uses methods such as zero-breaking equalization and MMSE (Minimum Mean Square Error), which are computationally complex (ICI elimination involves numerous matrix multiplications and divisions). The computational complexity and latency increase linearly with the number of iterations. Furthermore, the computational complexity and latency increase significantly with the number of data transmission slots, failing to meet the low-latency constraints of satellite communication.

[0006] In summary, the existing technology has the following drawbacks: 1) Existing technologies rely on the continuity of data time slots. If the data slots are not continuous, the channel estimation cannot quickly track changes in the channel, which leads to a sharp deterioration in performance.

[0007] 2) In low signal-to-noise ratio scenarios, the accuracy of pilot LS (Least Squares Estimation) estimation is limited, which in turn leads to limited accuracy of the channel estimation value of the interpolated data part.

[0008] 3) Iterative channel estimation can improve the frequency offset estimation accuracy in high-speed mobile scenarios by continuously selecting generations. Theoretically, more iterations will improve the estimation accuracy, but the complexity increases sharply with the number of generations, which cannot meet the low latency constraints of satellite communication. Summary of the Invention

[0009] To address the aforementioned problems in the existing technology, this invention provides an adaptive joint channel estimation method and apparatus based on time diversity technology. The technical problem to be solved by this invention is achieved through the following technical solution: In a first aspect, embodiments of the present invention provide an adaptive joint channel estimation method based on time diversity technology, the adaptive joint channel estimation method comprising: After receiving the data, the frequency domain data of the TB block with bound time slots is obtained by downsampling and OFDM demodulation. The first received demodulation reference signal corresponding to each OFDM symbol in each time slot of the TB block with bound time slots is extracted from the frequency domain data. According to the protocol configuration, the known transmit demodulation reference signal corresponding to each OFDM symbol in each time slot of the TB block with bound time slots is generated; Based on the frequency domain data, the first received demodulation reference signal, and the known transmitted demodulation reference signal, adaptive joint channel estimation is performed on each partial time slot block in the TB block of the bound time slot to obtain the estimated transmitted data corresponding to each time slot in each partial time slot block; wherein, the partial time slot block is a time slot block composed of all time slots that are temporally continuous in the TB block of the bound time slot; The estimated transmission data corresponding to each time slot in all partial time slot blocks are concatenated and decoded to obtain the transmission information of the TB block with bound time slots.

[0010] In one embodiment of the present invention, if each time slot in the TB block of the bound time slot is a single time slot, then the number of partial time slot blocks is the same as the number of time slots in the TB block of the bound time slot.

[0011] In one embodiment of the present invention, if all time slots in a TB block bound to a time slot are temporally continuous, then the number of partial time slot blocks is 1.

[0012] In one embodiment of the present invention, if all time slots in a TB block bound to a time slot are discontinuous in time, the number of partial time slot blocks is less than the number of time slots in a TB block bound to a time slot, and the number of partial time slot blocks depends on the discontinuity in time.

[0013] In one embodiment of the present invention, adaptive joint channel estimation is performed on each partial time slot block in the bound time slot TB block based on the frequency domain data, the first received demodulation reference signal, and the known transmitted demodulation reference signal to obtain the corresponding transmitted data, including: For each segment of a TB block with bound time slots, the execution process includes: performing channel estimation based on the first received demodulation reference signal and the known transmitted demodulation reference signal to obtain the channel estimation value corresponding to each OFDM symbol in each time slot of the segment of the time slot block; calculating the average noise signal power value corresponding to the segment of the time slot block based on the channel estimation value and the known transmitted demodulation reference signal; calculating adaptive filtering coefficients based on the average noise signal power value, and using the adaptive filtering coefficients to perform noise reduction filtering on the channel estimation value to obtain the channel estimation correction value corresponding to each OFDM symbol in each time slot of the segment of the time slot block; Frequency offset estimation is performed based on the channel estimation correction value to obtain the frequency offset estimate value corresponding to each OFDM symbol in each time slot of this part of the time slot block. The average frequency offset estimate value of this part of the time slot block is obtained by averaging all the frequency offset estimates. Frequency offset estimation compensation is performed on the channel estimation correction value based on the average frequency offset estimate value to obtain the corrected channel estimate value. The channel estimate value of all subcarriers corresponding to each OFDM symbol in each time slot of this part of the time slot block is recovered based on the corrected channel estimate value. The estimated transmission data corresponding to each time slot of this part of the time slot block is calculated based on the channel estimate value of all subcarriers and the frequency domain data.

[0014] In one embodiment of the present invention, calculating the average noise signal power value corresponding to this portion of the time slot block based on the channel estimate and the known transmitted demodulation reference signal includes: Calculate the second receive demodulation reference signal corresponding to each OFDM symbol in this part of the time slot block based on the channel estimate and the known transmit demodulation reference signal; The noise signal is calculated based on the first received demodulation reference signal and the second received demodulation reference signal, and the average noise signal is obtained by averaging the noise signals corresponding to all OFDM symbols in this part of the time slot block. The average noise signal power value corresponding to this part of the time slot block is calculated based on the average noise signal.

[0015] In one embodiment of the present invention, calculating the estimated transmission data corresponding to each time slot in this portion of the time slot block based on the channel estimates of all subcarriers and the frequency domain data includes: Calculate the equalized channel estimate for each OFDM symbol in each time slot within this part of the time slot block based on the channel estimates of all subcarriers; The estimated transmission data for each time slot in this part of the time slot block is calculated based on the equalized channel estimate and the frequency domain data.

[0016] Secondly, embodiments of the present invention provide an adaptive joint channel estimation device based on time diversity technology, the adaptive joint channel estimation device comprising: The extraction module is used to receive data and obtain the frequency domain data of the TB block of the bound time slot after downsampling and OFDM demodulation, and extract the first received demodulation reference signal corresponding to each OFDM symbol in each time slot of the TB block of the bound time slot from the frequency domain data; The generation module is used to generate the known transmit demodulation reference signal corresponding to each OFDM symbol in each time slot of the TB block with bound time slots according to the protocol configuration; An adaptive joint estimation module is used to perform adaptive joint channel estimation on each partial time slot block in the TB block of the bound time slots based on the frequency domain data, the first received demodulation reference signal, and the known transmitted demodulation reference signal, to obtain the estimated transmitted data corresponding to each time slot in each partial time slot block of the TB block of the bound time slots; wherein, a partial time slot block is a time slot block composed of all time slots that are temporally continuous in the TB block of the bound time slots; The splicing and decoding module is used to splice and decode the estimated transmission data corresponding to each time slot in all partial time slot blocks to obtain the transmission information of the TB block with bound time slots.

[0017] The beneficial effects of this invention are: This invention proposes an adaptive joint channel estimation method based on time diversity technology. It performs joint channel estimation between OFDM symbols within a partial time slot block. The same processing flow can be repeated between partial time slot blocks, unaffected by frame structure (whether time slots are continuous or not). This method better adapts to flexible time slot systems, enhances system compatibility, and supports different time diversity modes, including single-time slot, cross-time slot, and continuous time slot. Since a partial time slot block contains multiple OFDM symbols, joint channel estimation within this block, combined with averaging of observation noise and frequency offset, improves channel estimation accuracy in extreme scenarios with low signal-to-noise ratio and large frequency offset. This invention addresses the adaptability of channel estimation through adaptive filtering based on channel state, enhancing channel tracking capabilities in extreme scenarios with low signal-to-noise ratio and large frequency offset. This helps overcome the Doppler effect in high-speed mobile environments, improving channel estimation accuracy. As a non-iterative system, this invention has a simpler processing flow and lower computational complexity than iterative systems. The computational complexity does not increase linearly with the number of iterations, which is beneficial for engineering and meeting the time delay constraints of low-Earth orbit satellite communication. This invention employs time diversity and adaptive joint channel estimation techniques, which lowers the minimum threshold for communication demodulation, ensures communication quality in extreme scenarios, improves link reliability and resilience, and provides an evolutionary approach for expanding the coverage depth and optimizing the coverage continuity of low-Earth orbit satellite networks.

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] Figure 1This is a schematic diagram of the transmission mechanism for the three transmission slot types of existing bound time slot TB blocks; Figure 2 This is a flowchart illustrating an adaptive joint channel estimation method based on time diversity technology provided in an embodiment of the present invention. Figure 3 This is a more detailed flowchart of the single-slot-level adaptive joint channel estimation method based on time diversity technology provided in the embodiments of the present invention; Figure 4 This is a more detailed flowchart of the adaptive joint channel estimation method based on time diversity technology at the continuous time slot level provided in the embodiments of the present invention; Figure 5 This is a more detailed flowchart of the adaptive joint channel estimation method based on time diversity technology across time slots provided in the embodiments of the present invention; Figure 6 This is a schematic diagram of an adaptive joint channel estimation device based on time diversity technology provided in an embodiment of the present invention. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0021] The inventors' research also revealed that with the development boom of low-Earth orbit (LEO) satellite internet such as OneWeb and SpaceX, LEO satellite communication has developed rapidly. Its broadband high-frequency technology can provide enormous capacity, but Ka-band signals have poor penetration. For satellite communication, the longer satellite-to-ground distance leads to more severe propagation loss than terrestrial communication. Furthermore, the limited antenna gain due to payload size constraints results in a small budget margin for satellite communication links. In extreme channel conditions such as extremely low signal-to-noise ratios and high Doppler change rates, communication is often not guaranteed in LEO satellite communication. Therefore, to ensure communication quality under extreme channel conditions, this invention provides an adaptive joint channel estimation method and apparatus based on time diversity technology. By proposing a new enhancement scheme to improve the accuracy of satellite-to-ground link channel state estimation, the reliability of LEO satellite communication is improved.

[0022] Firstly, please see Figure 2 This invention provides an adaptive joint channel estimation method based on time diversity technology, which includes: S10. After receiving the data, the frequency domain data of the TB block with bound time slots is obtained by downsampling and OFDM demodulation. The first received demodulation reference signal corresponding to each OFDM symbol in each time slot of the TB block with bound time slots is extracted from the frequency domain data.

[0023] In this embodiment of the invention, the received data is downsampled and then demodulated using OFDM to obtain the frequency domain data of a TB block with bound time slots. Each time slot in the TB block contains multiple OFDM symbols. The frequency domain data corresponding to the j-th OFDM symbol in the i-th time slot of the TB block is denoted as Y. ofdm,i,j , where i is the slot number in the TB block of the bound slot, i=1, 2, ..., N, and N is the maximum bound slot number, with a minimum value of 1. j is the OFDM symbol number within each slot, j=1, 2, ..., M, where M is the maximum number of OFDM symbols within each slot, and the value of M is configured according to the NTN protocol. From frequency domain data Y ofdm,i,j Extract the data information and demodulation reference signal, denoted as Y respectively. data,i,j and Y dmrs,i,j Y data,i,j Y represents the data information corresponding to the j-th OFDM symbol in the i-th time slot of the TB block bound to the time slot. dmrs,i,j This represents the demodulation reference signal corresponding to the j-th OFDM symbol in the i-th time slot of the TB block with bound time slots, i.e., the first receive demodulation reference signal.

[0024] S20. Generate the known transmit demodulation reference signal corresponding to each OFDM symbol in each time slot of the TB block with bound time slots according to the protocol configuration. This can be generated using existing technology. The generated known transmit demodulation reference signal is denoted as X. dmrs,i,j X dmrs,i,j This represents the known transmit demodulation reference signal corresponding to the j-th OFDM symbol in the i-th time slot of the TB block with bound time slots.

[0025] S30. Based on the frequency domain data, the first received demodulation reference signal, and the known transmitted demodulation reference signal, adaptive joint channel estimation is performed on each partial time slot block in the TB block of the bound time slot to obtain the estimated transmitted data corresponding to each time slot in each partial time slot block of the TB block of the bound time slot; wherein, the partial time slot block is a time slot block composed of all time slots that are temporally continuous in the TB block of the bound time slot.

[0026] This invention employs adaptive joint channel estimation based on partial time slot blocks. The core idea is to calculate the noise signal power among OFDM symbols within each partial time slot block, then combine and average it before adaptive filtering. Next, the frequency offset value is calculated among OFDM symbols within each partial time slot block, combined and averaged before compensation. Then, the channel estimate value for each OFDM symbol in the partial time slot block is calculated. Finally, the transmitted data of the partial time slot block is obtained through equalization. Finally, the above method is repeated for each partial time slot block to obtain the transmitted information of the entire bound time slot TB block. The system is configured with different time slots as follows: Figure 1As shown, if each time slot in the TB block of the bound time slot is a single time slot (each user in each time slot is independent), then each time slot is considered as a partial time slot block, and the number of partial time slots in the TB block of the bound time slot is the same as the number of all time slots. If all time slots in the TB block of the bound time slot are temporally continuous, that is, continuous time slots (multiple time slots have the same user, and when all users in all time slots are the same, it is equivalent to 1 time slot block), then the number of partial time slot blocks is 1. If all time slots in the TB block of the bound time slot are temporally discontinuous, that is, spanning multiple time slots (users are in multiple time slots), then the number of partial time slot blocks is less than the number of time slots in the TB block of the bound time slot, and the number of partial time slot blocks depends on the temporally discontinuous situation.

[0027] This invention embodiment performs adaptive joint channel estimation on each partial time slot block in a bound time slot TB block based on frequency domain data, a first received demodulation reference signal, and a known transmitted demodulation reference signal to obtain corresponding transmitted data. The process includes: for each partial time slot block in the bound time slot TB block, the steps are as follows: performing channel estimation based on the first received demodulation reference signal and the known transmitted demodulation reference signal to obtain a channel estimation value corresponding to each OFDM symbol in each time slot of that partial time slot block; calculating the average noise signal power value corresponding to that partial time slot block based on the channel estimation value and the known transmitted demodulation reference signal; calculating adaptive filtering coefficients based on the average noise signal power value; and using the adaptive filtering coefficients to perform noise reduction filtering on the channel estimation value. The process involves obtaining the channel estimation correction value for each OFDM symbol within each time slot of the specified time slot block; performing frequency offset estimation based on the channel estimation correction value to obtain the frequency offset estimate value for each OFDM symbol within each time slot of the specified time slot block; averaging all frequency offset estimates within the specified time slot block to obtain the average frequency offset estimate value; compensating for the channel estimation correction value based on the average frequency offset estimate value to obtain the corrected channel estimate value; and recovering the channel estimate values ​​for all subcarriers corresponding to each OFDM symbol within each time slot of the specified time slot block based on the corrected channel estimate value; and calculating the estimated transmission data for each time slot of the specified time slot block based on the channel estimate values ​​for all subcarriers and frequency domain data. More specifically: Taking the z-th partial time slot block in a TB block with bound time slots as an example, the adaptive joint channel estimation for the z-th partial time slot block includes: Using the first received demodulation reference signal Y dmrs,i,j and the known transmitted demodulation reference signal X dmrs,i,j Channel estimation (such as the LS algorithm) is performed to obtain the channel estimate value corresponding to each OFDM symbol in each time slot of this part of the time slot block, denoted as H. dmrs,i,j H dmrs,i,j This represents the channel estimate corresponding to the j-th OFDM symbol within the i-th time slot of a partial time slot block. Based on the channel estimate H within the partial time slot block...dmrs,i,j and the known transmitted demodulation reference signal X dmrs,i,j Calculate the average noise signal power value of this time slot block, denoted as P. noise,z P noise,z Let P represent the average noise signal power value of the z-th time slot block. Based on the average noise signal power value P... noise,z Calculate the channel estimate H dmrs,i,j The adaptive filter coefficients (such as those obtained using Wiener filtering) are denoted as coe. dmrs,i,j ,coe dmrs,i,j This represents the adaptive filtering coefficients corresponding to the j-th OFDM symbol within the i-th time slot of a partial time slot block, and is applied to the channel estimate H. dmrs,i,j Noise reduction filtering is performed to obtain the channel estimation correction value corresponding to each OFDM symbol in each time slot of this part of the time slot block, denoted as H`. dmrs,i,j H` dmrs,i,j This represents the channel estimation correction value corresponding to the j-th OFDM symbol within the i-th time slot of a partial time slot block. Based on the channel estimation correction value H` dmrs,i,j Frequency offset estimation (e.g., using differential correlation) is performed to obtain the estimated frequency offset value for each OFDM symbol within each time slot of this portion of the time slot block, denoted as fo. i,j In a partial time-slot block, multiple fo within each time slot i,j The frequency offset estimate of a portion of the time slot block is obtained by averaging, denoted as fo. z ,fo z This represents the frequency offset estimate for the z-th time slot block. The channel estimation correction value H` is... dmrs,i,j Frequency offset estimation compensation is performed to obtain the corrected channel estimate for each OFDM symbol in each time slot of this part of the time slot block, denoted as H`` dmrs,i,j H`` dmrs,i,j This represents the corrected channel estimate corresponding to the j-th OFDM symbol within the i-th time slot of a partial time slot block, based on H`` dmrs,i,j Recover (e.g., through interpolation or duplication) the channel estimates for all subcarriers corresponding to each OFDM symbol within each time slot of a partial time slot block, denoted as H. ofdm,i,j H ofdm,i,j This represents the channel estimate for all subcarriers corresponding to the j-th OFDM symbol within the i-th time slot of a partial time slot block. Based on the channel estimates H of all subcarriers... ofdm,i,j and carrier frequency data Y ofdm,i,j Calculate the estimated transmission data for each time slot in this time slot block, denoted as Y`. ofdm,i Y` ofdm,iThis represents the estimated transmission data corresponding to the i-th time slot in a partial time slot block. Repeating the above process, calculate the estimated transmission data corresponding to each time slot in each partial time slot block of the bound time slot TB block, and then calculate the estimated transmission data for the entire bound time slot TB block.

[0028] The joint channel estimation method for OFDM symbols within a partial time slot block provided by this invention is not constrained by a specific channel estimation algorithm. It can be adapted to conventional channel estimation algorithms such as LS, ZF, MMSE, etc., as well as Kallmann filtering algorithm or LMS algorithm, etc.

[0029] This embodiment of the invention calculates the average noise signal power value corresponding to a portion of the time slot block based on channel estimation and a known transmit demodulation reference signal, including: calculating a second receive demodulation reference signal corresponding to each OFDM symbol within the portion of the time slot block based on channel estimation and a known transmit demodulation reference signal; calculating a noise signal based on the first receive demodulation reference signal and the second receive demodulation reference signal; averaging the noise signals corresponding to all OFDM symbols within the portion of the time slot block to obtain an average noise signal; and calculating the average noise signal power value corresponding to the portion of the time slot block based on the average noise signal. More specifically: Through H dmrs,i,j *X dmrs,i,j Calculate the second received demodulation reference signal, denoted as Y` dmrs,i,j Y` dmrs,i,j This represents the second receive demodulation reference signal corresponding to the j-th OFDM symbol within the i-th time slot of a partial time slot block. (Y) dmrs,i,j -Y` dmrs,i,j The noise signal is obtained and denoted as Y. noise,i,j Y noise,i,j This represents the noise signal corresponding to the j-th OFDM symbol within the i-th time slot of a partial time slot block. The average noise signal, denoted as Y, is obtained by averaging all noise signals within the partial time slot block. noise_mean,z Y noise_mean,z This represents the average noise signal of the z-th time slot block. The average noise signal power value, denoted as P, is then calculated based on this average noise signal. noise,z P noise,z =Y noise_mean,z *conj(Y noise_mean,z ), conj represents conjugate. Average noise signal power value P noise,z This represents the linear value of the signal-to-noise ratio.

[0030] This embodiment of the invention calculates the estimated transmission data corresponding to each time slot in this portion of the time slot block based on the channel estimates of all subcarriers and frequency domain data, including: calculating the equalized channel estimate corresponding to each OFDM symbol in each time slot of this portion of the time slot block based on the channel estimates of all subcarriers; and calculating the estimated transmission data corresponding to each time slot of this portion of the time slot block based on the equalized channel estimates and frequency domain data. More specifically: By using equalization methods (such as ZF / MMSE), based on the channel estimates H of all subcarriers... ofdm,i,j The equalized channel estimate is calculated and denoted as G. ofdm,i,j G ofdm,i,j This represents the equalized channel estimate corresponding to the j-th OFDM symbol within the i-th time slot of a partial time slot block. (Y`) ofdm,i =G ofdm,i,j *Y ofdm,i,j The estimated transmitted data, Y`, corresponds to each time slot in the calculation section of the time slot block. ofdm,i This represents the estimated transmitted data corresponding to the i-th time slot in a partial time slot block.

[0031] S40. Concatenate and decode the estimated transmission data corresponding to each time slot in all partial time slot blocks to obtain the transmission information of the TB block of the bound time slot.

[0032] In this embodiment of the invention, the estimated transmission data Y` corresponding to each time slot in all partial time slot blocks will be transmitted. ofdm,i The estimated transmitted data Y' needs to be decoded and concatenated into a TB block of bound time slots according to the order specified by the sender (deinterleaving). ofdm Then, the unified decoding is used to obtain the transmission information of the TB block bound to the time slot, which is usually referred to as the payload information.

[0033] This invention, in its embodiments, performs adaptive channel estimation on each segment of a bound time slot TB block, calculates the channel observation signal-to-noise ratio (SNR) and frequency offset, compensates for and equalizes the frequency offset, and finally concatenates the transmitted data of the entire bound time slot TB block for decoding to complete the channel estimation. For example, when the system is configured with different time slots... Figure 1 As shown, this includes single-slot, continuous-slot, and cross-slot configurations. Figure 3 This illustrates the adaptive joint channel estimation process at the single-slot level when each slot in a TB block with bound slots is processed in a single-slot manner. Figure 4 This illustrates the continuous time slot level processing method in the TB block with bound time slots, and the adaptive joint channel estimation processing flow for continuous time slots; Figure 5 This illustrates the adaptive joint channel estimation process at the cross-slot level when the slots in a bound slot TB block are processed across slots. As can be seen: Figure 3 , Figure 4 , Figure 5 The processes are the same, except that the number of repetitions of the processing of some time slot blocks is different for different time slot types. The number of corresponding partial time slot blocks at the single time slot level is N, and it is repeated N times. The number of corresponding partial time slot blocks at the continuous time slot level is 1, and it is only executed once. The number of corresponding partial time slot blocks across time slots is Z (the value of Z depends on the discontinuous situation in time, 1 < Z < N), and it is repeated Z times. Therefore, it is not affected by the frame structure of whether the time slots are continuous, enhancing the system compatibility.

[0034] To verify the effectiveness of the adaptive joint channel estimation method based on time diversity technology provided by the embodiments of the present invention, the following experiments are carried out for verification.

[0035] For the PUSCH uplink channel, the subcarrier spacing is 120 kHz, the DMRS position is [2, 6, 9], the MCS is 20, the frequency offset is 10 kHz, and 50000 time slot data is transmitted. Simulations are carried out on the PUSCH block error rate threshold for 1 / 8 / 16 / 32 times of time diversity respectively. Theoretically, for the PUSCH signal with 1 time of time diversity, the single time slot process is followed for one demodulation process; for the PUSCH signals with 8 / 16 / 32 times of time diversity, the continuous time slot process is followed for one demodulation process. At this time, the gain of combining noise and frequency offset estimation is the largest. The block error rate thresholds after the final decoding are shown in Table 1.

[0036] Table 1 Simulation results of joint channel estimation of PUSCH signals

[0037] Aiming at the problems of small communication link budget margin, insufficient coverage, and weak anti-Doppler effect ability in low-earth orbit satellite communication, the present invention conducts research on the technology of low-earth orbit satellite-satellite channel estimation. It can be seen from Table 1 that the demodulation performance is improved by 8.8 dB under 8 times of time diversity. The research results can reduce the minimum threshold of communication demodulation, ensure the communication quality in extreme scenarios, and provide an evolutionary idea for optimizing the coverage stability of low-earth orbit satellite networks.

[0038] In summary, the adaptive joint channel estimation method based on time diversity proposed in this invention performs joint channel estimation between OFDM symbols within a partial time slot block. The same processing flow can be repeated between partial time slot blocks, unaffected by frame structure (whether time slots are continuous or not). This allows for better adaptation to flexible time slot systems, enhancing system compatibility and supporting different time diversity modes, including single-time slot, cross-time slot, and continuous time slot. Since a partial time slot block contains multiple OFDM symbols, joint channel estimation within this block, combined with averaging of observation noise and frequency offset, improves channel estimation accuracy in extreme scenarios such as low signal-to-noise ratio (SNR) and large frequency offset. Furthermore, this invention addresses the adaptability of channel estimation through adaptive filtering based on channel state, enhancing channel tracking capabilities in extreme scenarios such as low SNR and large frequency offset. This is beneficial for overcoming the Doppler effect in high-speed mobile environments, further improving channel estimation accuracy. This invention presents a non-iterative system with a simpler processing flow and lower computational complexity compared to iterative systems. The computational complexity does not increase linearly with the number of iterations, which is beneficial for engineering applications and meeting the latency constraints of low-Earth orbit (LEO) satellite communication. This invention employs time diversity and adaptive joint channel estimation techniques, lowering the minimum threshold for communication demodulation, ensuring communication quality in extreme scenarios, and improving the reliability and resilience of the link. It also provides an evolutionary approach for expanding the coverage depth and optimizing the coverage continuity of LEO satellite networks.

[0039] Secondly, please see Figure 6 This invention provides an adaptive joint channel estimation device based on time diversity technology, which includes: The extraction module is used to receive data and obtain the frequency domain data of the TB block of the bound time slot after downsampling and OFDM demodulation, and extract the first received demodulation reference signal corresponding to each OFDM symbol in each time slot of the TB block of the bound time slot from the frequency domain data; The generation module is used to generate the known transmit demodulation reference signal corresponding to each OFDM symbol in each time slot of the TB block with bound time slots according to the protocol configuration; The adaptive joint estimation module is used to perform adaptive joint channel estimation on each partial time slot block in the TB block of the bound time slots based on frequency domain data, the first received demodulation reference signal and the known transmitted demodulation reference signal, so as to obtain the estimated transmitted data corresponding to each time slot in each partial time slot block; wherein, the partial time slot block is a time slot block composed of all time slots that are temporally continuous in the TB block of the bound time slots; The splicing and decoding module is used to splice and decode the transmission data corresponding to each OFDM symbol in each time slot of all partial time slot blocks to obtain the transmission information of the TB block of the bound time slot.

[0040] As the apparatus embodiment of the second aspect is basically similar to the method embodiment of the first aspect, the description is relatively simple, and relevant details can be found in the description of the method embodiment of the first aspect.

[0041] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0042] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the specification and accompanying drawings, will understand and implement other variations of the disclosed embodiments in carrying out the claimed invention. In the specification, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. While certain measures are described in different embodiments, this does not mean that these measures cannot be combined to produce good results.

[0043] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. An adaptive joint channel estimation method based on time diversity technology, characterized in that, The adaptive joint channel estimation method includes: After receiving the data, the frequency domain data of the TB block with bound time slots is obtained by downsampling and OFDM demodulation. The first received demodulation reference signal corresponding to each OFDM symbol in each time slot of the TB block with bound time slots is extracted from the frequency domain data. According to the protocol configuration, the known transmit demodulation reference signal corresponding to each OFDM symbol in each time slot of the TB block with bound time slots is generated; Based on the frequency domain data, the first received demodulation reference signal, and the known transmitted demodulation reference signal, adaptive joint channel estimation is performed on each partial time slot block in the TB block of the bound time slot to obtain the estimated transmitted data corresponding to each time slot in each partial time slot block; wherein, the partial time slot block is a time slot block composed of all time slots that are temporally continuous in the TB block of the bound time slot; The estimated transmission data corresponding to each time slot in all partial time slot blocks are concatenated and decoded to obtain the transmission information of the TB block with bound time slots.

2. The adaptive joint channel estimation method based on time diversity technology according to claim 1, characterized in that, If each time slot in a TB block with bound time slots is a single time slot, the number of partial time slot blocks is the same as the total number of time slots in the TB block with bound time slots.

3. The adaptive joint channel estimation method based on time diversity technology according to claim 1, characterized in that, If all time slots in a TB block bound to a time slot are temporally continuous, the number of partial time slot blocks is 1.

4. The adaptive joint channel estimation method based on time diversity technology according to claim 1, characterized in that, If all time slots in a bound time slot TB block are discontinuous in time, the number of some time slot blocks is less than the total number of time slots in the bound time slot TB block, and the number of some time slot blocks depends on the discontinuity in time.

5. The adaptive joint channel estimation method based on time diversity technology according to claim 1, characterized in that, Based on the frequency domain data, the first received demodulation reference signal, and the known transmitted demodulation reference signal, adaptive joint channel estimation is performed on each partial time slot block in the bound time slot TB block to obtain the corresponding transmitted data, including: For each segment of a TB block with bound time slots, the execution process includes: performing channel estimation based on the first received demodulation reference signal and the known transmitted demodulation reference signal to obtain the channel estimation value corresponding to each OFDM symbol in each time slot of the segment of the time slot block; calculating the average noise signal power value corresponding to the segment of the time slot block based on the channel estimation value and the known transmitted demodulation reference signal; calculating adaptive filtering coefficients based on the average noise signal power value, and using the adaptive filtering coefficients to perform noise reduction filtering on the channel estimation value to obtain the channel estimation correction value corresponding to each OFDM symbol in each time slot of the segment of the time slot block; based on... The channel estimation correction value is used to perform frequency offset estimation to obtain the frequency offset estimate value corresponding to each OFDM symbol in each time slot of the partial time slot block. The average frequency offset estimate value corresponding to the partial time slot block is obtained by averaging all the frequency offset estimates. The channel estimation correction value is then compensated for by frequency offset estimation based on the average frequency offset estimate value to obtain the corrected channel estimate value. The channel estimate value of all subcarriers corresponding to each OFDM symbol in each time slot of the partial time slot block is recovered based on the corrected channel estimate value. The estimated transmission data corresponding to each time slot of the partial time slot block is calculated based on the channel estimate value of all subcarriers and the frequency domain data.

6. The adaptive joint channel estimation method based on time diversity technology according to claim 5, characterized in that, The average noise signal power value corresponding to this portion of the time slot block is calculated based on the channel estimate and the known transmitted demodulation reference signal, including: Calculate the second receive demodulation reference signal corresponding to each OFDM symbol in each time slot of this part of the time slot block based on the channel estimate and the known transmit demodulation reference signal; The noise signal is calculated based on the first received demodulation reference signal and the second received demodulation reference signal. The average noise signal is obtained by averaging the noise signals corresponding to all OFDM symbols in each time slot of this part of the time slot block. The average noise signal power value corresponding to this part of the time slot block is calculated based on the average noise signal.

7. The adaptive joint channel estimation method based on time diversity technology according to claim 5, characterized in that, Based on the channel estimates of all subcarriers and the frequency domain data, the estimated transmission data corresponding to each time slot in this portion of the time slot block is calculated, including: Calculate the equalized channel estimate for each OFDM symbol in each time slot within this part of the time slot block based on the channel estimates of all subcarriers; The estimated transmission data for each time slot in this part of the time slot block is calculated based on the equalized channel estimate and the frequency domain data.

8. An adaptive joint channel estimation device based on time diversity technology, characterized in that, The adaptive joint channel estimation device includes: The extraction module is used to receive data and obtain the frequency domain data of the TB block of the bound time slot after downsampling and OFDM demodulation, and extract the first received demodulation reference signal corresponding to each OFDM symbol in each time slot of the TB block of the bound time slot from the frequency domain data; The generation module is used to generate the known transmit demodulation reference signal corresponding to each OFDM symbol in each time slot of the TB block with bound time slots according to the protocol configuration; An adaptive joint estimation module is used to perform adaptive joint channel estimation on each partial time slot block in the TB block of the bound time slots based on the frequency domain data, the first received demodulation reference signal, and the known transmitted demodulation reference signal, to obtain the estimated transmitted data corresponding to each time slot in each partial time slot block of the TB block of the bound time slots; wherein, a partial time slot block is a time slot block composed of all time slots that are temporally continuous in the TB block of the bound time slots; The splicing and decoding module is used to splice and decode the estimated transmission data corresponding to each time slot in all partial time slot blocks to obtain the transmission information of the TB block with bound time slots.

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