Downlink precoding method and device, electronic equipment, storage medium and program

Abstract

The invention discloses a downlink precoding method and device, electronic equipment, a storage medium and a program, and is applied to a sending end, the method comprises the following steps: obtaining communication configuration information, and determining an average interference power leakage coefficient of different users on scheduled subcarriers according to the communication configuration information; determining an average channel power and an array response vector of each user based on the communication configuration information; according to the average interference power leakage coefficient, the average channel power and the array response vector, determining a downlink precoding vector of each user according to an average signal leakage noise ratio maximization criterion; and obtaining a downlink transmission signal of each user, and performing weighting processing on the transmission signal of each downlink user according to the downlink precoding vector of each user, thereby obtaining a downlink transmission signal corresponding to each downlink transmission beam. According to the embodiment of the invention, the problem of asynchronous interference among different users in the mobile phone direct connection satellite communication system can be solved, and the downlink transmission performance of the multi-beam satellite mobile communication system can be improved.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a downlink precoding method, device, electronic device, storage medium and program. Background Art

[0002] Mobile phone direct satellites allow mobile phones to communicate directly with satellites, enabling global voice, text messaging, and data transmission, providing satellite Internet services to a wide range of public consumers. In recent years, existing mobile phone direct satellites have gradually become a new hotspot in satellite mobile communications. By cooperating with ground communication operators, existing mobile phone direct satellites share low-frequency spectrum resources in terrestrial cellular networks and provide satellite network services to hundreds of millions of existing commercial mobile phone terminals. Existing mobile phone direct satellites reuse terrestrial 4G / 5G frequencies, using low Earth orbit (LEO) satellites to cover ground terminals, and using large-scale onboard phased array antennas to increase antenna gain to meet the link requirements of existing mobile phone direct satellites. Beamforming technology is used to generate sufficiently small spot beams to cover the ground area. Each beam coverage area corresponds to a cell in the ground cellular system.

[0003] Currently, in scenarios where existing mobile phones connect directly to satellites, each beam is a separate cell. The satellite performs time-frequency correction on the transmit and receive signals on each beam, causing frequency and time synchronization between the transmit and receive signals. This results in inter-carrier interference (ICI) and inter-symbol interference (ISI) between different users, disrupting the orthogonality of the orthogonal frequency division multiplexing (OFDM) system. To reduce asynchronous interference between beams, methods such as frequency multi-color multiplexing and increasing beam spacing can be used. Frequency multi-color multiplexing uses different frequency resources between adjacent beams. However, low-band frequency resources used for existing mobile phones connecting directly to satellites are extremely scarce, and multi-color multiplexing further reduces the available bandwidth of each beam. While increasing beam spacing can reduce inter-beam interference, users between point beams will be unable to access the satellite network. Even if beam scanning is used, the system overhead and complexity are unacceptable, making satellite coverage a major challenge. Summary of the Invention

[0004] The present invention provides a downlink precoding method, device, electronic device, storage medium and program to solve the problem of asynchronous interference between different users in a mobile phone direct-to-satellite communication system, achieve accurate downlink precoding, and improve the downlink transmission performance of a multi-beam satellite mobile communication system.

[0005] According to one aspect of the present invention, a downlink precoding method is provided, wherein the method is applied to a transmitting end, wherein the method includes:

[0006] Acquire communication configuration information, and determine average interference power leakage coefficients of different users on the scheduled subcarriers based on the communication configuration information;

[0007] Determining an average channel power and an array response vector for each of the users based on the communication configuration information;

[0008] Determine a downlink precoding vector for each user according to the average interference power leakage coefficient, the average channel power and the array response vector according to an average signal-to-leakage-to-noise ratio maximization criterion;

[0009] A downlink transmission signal of each of the users is obtained, and weighted processing is performed on the downlink transmission signal according to the downlink precoding vector of each of the users, thereby obtaining a downlink transmission signal corresponding to each downlink transmission beam.

[0010] According to another aspect of the present invention, a downlink precoding device is provided, wherein the device is applied to a transmitting end and includes:

[0011] A power leakage coefficient determination module is used to obtain communication configuration information and determine the average interference power leakage coefficient of different users on the scheduled subcarriers according to the communication configuration information;

[0012] a channel power determination module, configured to determine an average channel power and an array response vector for each of the users based on the communication configuration information;

[0013] a precoding determination module, configured to determine a downlink precoding vector for each user according to a criterion of maximizing an average signal-to-leakage-and-noise ratio based on the average interference power leakage coefficient, the average channel power, and the array response vector;

[0014] The signal generating module is used to obtain the downlink transmission signal of each user, and perform weighted processing on the downlink transmission signal according to the downlink precoding vector of each user, so as to obtain the downlink transmission signal corresponding to each downlink transmission beam.

[0015] According to another aspect of the present invention, an electronic device is provided, comprising:

[0016] at least one processor; and

[0017] a memory communicatively connected to the at least one processor; wherein,

[0018] The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can perform the downlink precoding method described in any embodiment of the present invention.

[0019] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the downlink precoding method according to any embodiment of the present invention when executed.

[0020] According to another aspect of the present invention, a computer program product is provided, wherein the computer program product includes a computer program, and when the computer program is executed by a processor, the downlink precoding method according to any embodiment of the present invention is implemented.

[0021] The technical solution of the embodiment of the present invention obtains communication configuration information, determines the average interference power leakage coefficient of different users on their scheduled subcarriers according to the communication configuration information, and determines the parallel channel power and array response vector of each user. Based on the average signal-to-leakage-to-noise ratio maximization criterion, the downlink precoding vector of each user is determined based on the average interference power leakage coefficient, average channel power, and array response vector. The downlink transmission signal of each user is obtained, and the downlink transmission signal is weighted according to the downlink precoding vector of each user to obtain the downlink transmission signal corresponding to each downlink transmission beam. The embodiment of the present invention can solve the problem of asynchronous interference between different users in a mobile phone direct-connect satellite communication system and improve the downlink transmission performance of a multi-beam satellite mobile communication system.

[0022] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 This is a schematic diagram of multi-beam low-orbit satellite transmission provided by an embodiment of the present invention;

[0025] Figure 2 is a flowchart of a downlink precoding method provided according to an embodiment of the present invention;

[0026] Figure 3 is a flowchart of another downlink precoding method provided according to an embodiment of the present invention;

[0027] Figure 4 is a flowchart of another downlink precoding method provided according to an embodiment of the present invention;

[0028] Figure 5 is an exemplary diagram of a downlink precoding method provided according to an embodiment of the present invention;

[0029] FIG6( a ) is a schematic diagram of downlink beam coverage provided according to an embodiment of the present invention;

[0030] FIG6( b ) is a schematic diagram of downlink beam coverage provided according to an embodiment of the present invention;

[0031] FIG6( c ) is a schematic diagram of downlink beam coverage provided according to an embodiment of the present invention;

[0032] FIG6( d ) is a schematic diagram of downlink beam coverage provided according to an embodiment of the present invention;

[0033] FIG7( a ) is a comparison diagram of downlink performance under asynchronous interference according to an embodiment of the present invention;

[0034] FIG7( b ) is a comparison diagram of downlink performance under asynchronous interference according to an embodiment of the present invention;

[0035] FIG7( c ) is a comparison diagram of downlink performance under asynchronous interference according to an embodiment of the present invention;

[0036] FIG7( d ) is a comparison diagram of downlink performance under asynchronous interference according to an embodiment of the present invention;

[0037] Figure 8 2 is a schematic structural diagram of a downlink precoding device provided according to an embodiment of the present invention;

[0038] Figure 9 is an exemplary diagram of a downlink precoding method provided according to an embodiment of the present invention;

[0039] Figure 10 2 is a schematic structural diagram of a downlink precoding device provided according to an embodiment of the present invention;

[0040] Figure 11 It is a structural diagram of an electronic device for implementing the downlink precoding method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0042] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0043] Figure 1 : This is a schematic diagram of a multi-beam low-orbit satellite transmission according to an embodiment of the present invention. The satellite and the user terminal communicate directly. Taking a broadband multi-beam LEO satellite based on orthogonal frequency division multiplexing (OFDM) serving multiple user terminals at the same time as an example, the satellite side is configured with a uniform plane array (UPA). Each antenna unit is a digital active antenna. The number of antennas on the X-axis and Y-axis is M respectively. x and M y , the total number of antennas is The user side is equipped with a single antenna, and the spatial interval between different users is usually greater than several times the wavelength, so the channels between the satellite and different user devices can be considered unrelated. Figure 1 As shown, the satellite side generates K beams through the array antenna, each beam corresponds to a cell, and each cell has N U If each message is sent to the same number of users through resource scheduling, users in the cell use different subcarrier groups, and the subcarrier group divisions in different cells are the same.

[0044] Let the number of subcarriers be N sc , the subcarrier spacing is Δf, and the cyclic prefix (CP) length is N cp , the system sampling period is T s =1 / (Nsc Δf), then the time length of CP is T cp =N cp T s The OFDM symbol time lengths excluding and including CP are T sc =N sc T s and T = T cp +T sc . Note Φ k,n is the subcarrier set of the nth user in beam (cell) k, For all N U The effective subcarrier set of each user, is the effective number of subcarriers used for pilot and data transmission, then:

[0045]

[0046] That is, the same user group (same user index) in different beams uses the same frequency resources, and different users in the same beam use different frequency resources. represents the nth user in the kth beam, There are N users using the same subcarrier group for K beams. U User groups

[0047] remember is the frequency domain signal sent by the satellite to the nth user in beam k on the rth subcarrier of the sth OFDM symbol, and when hour, The corresponding downlink time domain transmission signal is:

[0048]

[0049] Where Δf = 1 / T sc , N sc is the number of subcarriers, j is a complex number, t is time, T cp is the time length of the CP, s is the OFDM symbol index, r is the subcarrier index, k is the beam index, n is the user index, and T is the time length of the OFDM symbol including the CP.

[0050] Then the transmitted signals of all users in beam k can be expressed as:

[0051]

[0052] remember is the beamforming vector of beam k, and satisfies Then the downlink transmission signal of the kth beam is:

[0053]

[0054] In the scenario where existing mobile phones are directly connected to satellites, in order to ensure that ordinary mobile phone terminals can directly access the satellite mobile communication network without any modification, the satellite side compensates / pre-compensates the receiving and transmitting signals based on the Doppler frequency shift and propagation delay at the center of each beam, eliminating the large Doppler frequency shift and propagation delay caused by satellite movement, and the maximum residual frequency deviation and residual time deviation within the beam coverage range must not exceed the range of the ground cellular system. Assume that the Doppler at the center of beam k is The propagation delay is Satellite side based on and The downlink transmission signal of beam k is pre-compensated, and the transmission signal after pre-compensation is:

[0055]

[0056] Therefore, the downlink transmission signals of all K beams on the satellite side can be expressed as:

[0057]

[0058] The time domain received signal of the nth user in beam k in the sth OFDM symbol is:

[0059]

[0060] g k,n,l are the channel gain, Doppler frequency shift, propagation delay and satellite array response vector of the nth user in beam k on the lth path, L k,n is the path number of the nth user in beam k. is the additive white Gaussian noise of the nth user in beam k on the sth OFDM symbol, obeying The Doppler shift in the satellite scenario consists of two parts, and the Doppler shifts of different multipaths on the satellite side are approximately the same, that is, represents the Doppler caused by the satellite motion, Indicates the Doppler caused by the user's motion. is the minimum propagation delay of the channel of user n in beam k, is the propagation delay caused by multipath on the user side, then Since the distance between the satellite and the user is far, the Angle of Departure (AOD) corresponding to different multipaths of the user is approximately the same, so g k,n,l =g k,n .remember represents the AoD of the nth user in beam k, then:

[0061]

[0062] in, Specifically:

[0063]

[0064] Where λ is the carrier wavelength, n v is the number of array elements along the v axis, d v is the spacing of the antennas along the v axis, v∈{x,y}. The AoD angle of the nth user in beam k is projected on the x-axis and y-axis directions of the array antenna. The spatial angle reflects the spatial characteristics of the user channel. and nadir angle The relationship between

[0065] Substituting formula (6) into formula (7), we can get

[0066]

[0067] in, Indicates the downlink interference caused by other users in the same beam, Indicates the downlink interference caused by users in other beams,

[0068]

[0069] are the equivalent channel gain, equivalent Doppler frequency shift and equivalent propagation delay of the nth user in beam k after propagation delay and Doppler pre-compensation respectively. and They represent the Doppler frequency shift difference and propagation delay difference caused by the user not being in the center of the beam. In the scenario where existing mobile phones are directly connected to satellites, and To maintain the Doppler frequency deviation and propagation delay range of the ground cellular communication system, the user terminal only needs to and Make an estimate and compensate. In addition, It is the Doppler frequency shift of the center point of beam i on the satellite side and propagation delay After pre-compensation, the equivalent channel gain, equivalent Doppler frequency shift and equivalent propagation delay of the lth path of the nth user in beam k are It may be larger than the OFDM tolerance range, or even larger than the subcarrier spacing, and the residual delay It may be greater than the CP length, or even greater than the OFDM symbol length, so that the received signal of user n in beam k is subject to frequency-asynchronous interference and time-asynchronous interference from users in other beams.

[0070] In formula (10) Indicates that user n in beam k receives signals from other users in the same beam. These other users are orthogonal to user n in frequency. After OFDM demodulation, these signals will not interfere with the received signal of user n. Therefore, this item can be ignored. represents the sum of interference and noise terms of users in other beams, then Equation (10) can be simplified to

[0071]

[0072] in, The variance of can be expressed as:

[0073]

[0074] in, is the downlink transmission power of the u-th user in the i-th beam on the satellite side, satisfying is the total downlink power of the satellite, is the noise variance of the nth user in the kth beam.

[0075] The frequency domain received signal of user n in beam k on the rth subcarrier of the sth OFDM symbol is:

[0076]

[0077] The equivalent channel frequency response of user n in beam k after Doppler shift and delay pre-compensation is defined as:

[0078]

[0079] The received signal in the frequency domain can be further expressed as:

[0080]

[0081] in, is the frequency domain equivalent noise term, and its variance is:

[0082]

[0083] in, is the u-th user in the i-th beam on the subcarrier The transmit power on is the noise variance of user n on subcarrier r in beam k. represents the subcarrier of user u in beam i The power leakage coefficient of the signal on the beam k due to frequency asynchrony and time asynchrony is related to the normalized frequency offset ε f , subcarrier spacing Normalized bias ε τ related, It can be expressed as:

[0084]

[0085] Among them, ε f =Δf d / Δf represents the normalized frequency offset between user u in beam i and user n in beam k relative to the subcarrier spacing, ε τ =Δτ / T s represents the normalized timing offset between user u in beam i and user n in beam k relative to the sampling interval, Δf d is the frequency deviation between the two, that is, the Doppler frequency shift difference, and Δτ is the time deviation between the two, that is, the propagation delay difference.

[0086] Figure 2 This is a flow chart of a downlink precoding method provided by an embodiment of the present invention. This embodiment is applicable to the case where a mobile phone is directly connected to a satellite communication. The method can be executed by a downlink precoding device, which can be implemented in the form of hardware and / or software and can be configured in a satellite side device. Figure 2 As shown, the method includes:

[0087] Step 110: Acquire communication configuration information, and determine average interference power leakage coefficients of different users on the scheduled subcarriers according to the communication configuration information.

[0088] Among them, the communication configuration information can be the configuration information for direct communication between the satellite side device and the mobile phone. The communication configuration information may include satellite ephemeris information, number of users, user location, user downlink time and frequency scheduling information, user beam correspondence, number of beams and beam configuration information, etc. Satellite ephemeris information may include satellite position, satellite motion speed, satellite status information, etc.; the number of users may be the number of users scheduled in each downlink transmission beam; the user position may be the location of each user; the user downlink time-frequency scheduling information may include the configuration information of the satellite scheduling user communication resources, and the user downlink time-frequency scheduling information may include time slot allocation, frequency domain allocation, Doppler pre-compensation indication, power control instructions, logical channel mapping, resource preemption indication, etc.; the user beam correspondence may be the mapping relationship between the user and the downlink transmission beam, and the user beam correspondence may include beam identification, user identification, association mark between the beam and the user, etc. The user beam correspondence may be specifically a dynamic relationship, and the user beam correspondence may change with the movement of the satellite or user equipment. The number of beams may be specifically the number of downlink transmission beams generated by the satellite; the beam configuration information may include the downlink carrier frequency and beam center position of the downlink transmission beam, etc.

[0089] In an embodiment of the present invention, the average interference power leakage coefficient may be the degree of signal interference on the subcarrier scheduled by each user in the downlink transmission beam caused by the subcarriers scheduled by other users in other downlink transmission beams. The average interference leakage coefficient may be specifically the average value of the ratio between the power of the subcarriers scheduled by all users in a downlink transmission beam and the power leaked from the subcarriers scheduled by other users in other downlink transmission beams.

[0090] Specifically, communication configuration information can be obtained. The communication configuration information can be set in a configuration module of the satellite. The communication configuration information can be periodically obtained in the configuration module. The average interference power leakage coefficient of each user on its scheduled subcarrier can be calculated according to the obtained communication configuration information. The calculation process can include determining the ratio of the downlink signal power transmitted by each user on its scheduled subcarrier to the downlink signal power of each user on its scheduled subcarrier that is leaked from other subcarriers scheduled by other users. It is understandable that each user can be located at the beam center of its corresponding downlink transmit beam.

[0091] Step 120: Determine the average channel power and array response vector of each user based on the communication configuration information.

[0092] In an embodiment of the present invention, the average channel power may be the average value of the signal power carried by the downlink signal sent by the user on its scheduled subcarrier. The average channel power may be determined by the relevant configuration information of the user and the satellite in the communication configuration information. For example, the communication configuration information may include satellite ephemeris information such as the satellite's orbital altitude, inclination, eccentricity, and other information such as the user's beam center position. The position information of the satellite and the user can be determined through the communication configuration information, and the free space loss and other losses of the downlink signal can be determined based on the position information. Then, the signal transmission power and user terminal antenna gain, free space loss, other losses and other parameters in the communication configuration information can be substituted into the communication distance equation to determine the average channel power of each user.

[0093] Specifically, the communication configuration information including the number of array elements along the x-axis and the y-axis, the antenna spacing of the array along the x-axis and the y-axis, the carrier wavelength, the satellite ephemeris information, and the user position can also be extracted. The satellite position can be determined according to the satellite ephemeris signal and the user position, and the AOD angle can be determined according to the satellite position and the user position. The array response vector of the user on the satellite side can be determined by the AOD angle and the number of array elements along the x-axis and the y-axis, the antenna spacing of the array along the x-axis and the y-axis, the carrier wavelength, and other information. In some embodiments, the array response vector of the user on the satellite side can be determined by equations (8) and (9).

[0094] Step 130: Determine the downlink precoding vector for each user according to the average interference power leakage coefficient, the average channel power and the array response vector and the average signal-to-leakage-to-noise ratio maximization criterion.

[0095] The average signal-to-leakage-to-noise ratio may be an average value of the ratio of the average channel power received at the user side to the sum of the interference power and the noise power of the signal leaked to other users.

[0096] Specifically, the interference signal power received by the user due to signal leakage of other users on other scheduled subcarriers can be determined based on the average interference power leakage coefficient of the user on the scheduled subcarrier, and the obtained interference signal power, average channel power, and array response vector can be substituted into a formula for determining the average signal-to-leakage-and-noise ratio. The determination formula may include noise power determined based on a downlink precoding vector, and the determination formula can be made to have a maximum value, so that the determination formula satisfies the average signal-to-leakage-and-noise ratio maximization criterion, and the downlink precoding vector when the determination formula has the maximum value is obtained.

[0097] Step 140: Acquire the downlink transmission signal of each downlink user, and perform weighted processing on the downlink transmission signal according to the downlink precoding vector of each user, so as to obtain the downlink transmission signal corresponding to each downlink transmission beam.

[0098] In an embodiment of the present invention, the downlink transmission signal of each downlink user can be obtained, the sent downlink transmission signal can be weighted according to the downlink precoding vector of each user, and the weighted result can be used as the downlink transmission signal of each downlink transmission beam.

[0099] An embodiment of the present invention obtains communication configuration information, determines the average interference power leakage coefficient of different users on their scheduled subcarriers according to the communication configuration information, and determines the parallel channel power and array response vector of each user. Based on the average signal-to-leakage-to-noise ratio maximization criterion, the downlink precoding vector of each user is determined based on the average interference power leakage coefficient, average channel power, and array response vector. The downlink transmission signal of each user is obtained, and the downlink transmission signal is weighted according to the downlink precoding vector of each user to obtain the downlink transmission signal corresponding to each downlink transmission beam. The embodiment of the present invention can solve the problem of asynchronous interference between different users in a mobile phone direct-connect satellite communication system and improve the downlink transmission performance of a multi-beam satellite mobile communication system.

[0100] Based on the above embodiments of the invention, the communication configuration information includes at least:

[0101] Satellite ephemeris information, number of users, user locations, user downlink time and frequency resource scheduling information, user beam correspondence, number of beams, and beam configuration information.

[0102] Specifically, the communication configuration information may be the configuration information for direct communication between the satellite side device and the mobile phone. The communication configuration information may include satellite ephemeris information, number of users, user location, user downlink time and frequency scheduling information, user beam correspondence, number of beams, and beam configuration information, etc. Satellite ephemeris information may include satellite position, satellite motion speed, satellite status information, etc.; the number of users may be the number of users scheduling subcarriers in each beam of the downlink transmission beam; the user position may be the location of each user; the user downlink time-frequency scheduling information may include the configuration information of the satellite scheduling user communication resources, and the user downlink time-frequency scheduling information may include time slot allocation, frequency domain allocation, Doppler pre-compensation indication, power control instructions, logical channel mapping, resource preemption indication, etc.; the user beam correspondence may be a mapping relationship between the user and the downlink transmission beam, and the user beam correspondence may include a beam identifier, a user identifier, an association mark between the beam and the user, etc. The user beam correspondence may be specifically a dynamic relationship, and the user beam correspondence may change with the movement of the satellite or user equipment. The number of beams may be specifically the number of downlink transmission beams generated by the satellite; the beam configuration information may include the downlink carrier frequency and beam center position of the downlink transmission beam, etc.

[0103] Furthermore, in some embodiments of the invention, the communication configuration information may also include satellite payload information, such as the operating status, power consumption, heat dissipation, and other information of the satellite equipment.

[0104] Figure 3 This is a flowchart of another downlink precoding method provided according to an embodiment of the present invention. The embodiment of the present invention is a specific embodiment based on the above embodiment, and the process of determining the average interference power leakage coefficient is described. Figure 3 The method provided in the embodiment of the present invention specifically includes the following steps:

[0105] Step 210: Acquire communication configuration information, and extract satellite ephemeris information and beam configuration information from the communication configuration information.

[0106] In an embodiment of the present invention, the satellite end can extract communication configuration information in the scheduling module. The communication configuration information may include satellite ephemeris information, the number of users, the user location, the user downlink time-frequency resource scheduling information, the user beam correspondence, the number of beams and the beam configuration information, etc. The satellite ephemeris information and the beam configuration information can be extracted from the communication configuration information.

[0107] Step 220: Determine the Doppler frequency shift difference and propagation delay difference between every two beam centers according to the satellite ephemeris information and the downlink carrier frequency and beam center position in the beam configuration information.

[0108] In an embodiment of the present invention, the downlink carrier frequency of the subcarrier of each downlink transmit beam and the beam center position of each downlink transmit beam can be extracted from the beam configuration information. The beam center position can be used as the user position, and the Doppler frequency shift and propagation delay corresponding to each beam center can be determined based on the satellite ephemeris information and the user position. The Doppler frequency shift and propagation delay corresponding to different beam centers can be differentiated to determine the Doppler frequency shift difference and propagation delay difference between each two beam centers.

[0109] Step 230: Determine average interference power leakage coefficients of different users on the scheduled subcarriers based on the communication configuration information, the Doppler frequency shift differences, and the propagation delay differences.

[0110] Specifically, the beam configuration information in the communication configuration information can be obtained, and the average interference power leakage coefficient caused by the influence of other subcarriers on the scheduled subcarriers of each user can be determined according to the number of subcarriers, cyclic prefix, subcarrier spacing and other information in the beam configuration information and the Doppler frequency shift difference and propagation delay difference between each two beam centers.

[0111] Step 240: Determine the average channel power and array response vector of each user based on the communication configuration information.

[0112] Step 250: Determine the downlink precoding vector for each user according to the average interference power leakage coefficient, the average channel power and the array response vector and the average signal-to-leakage-to-noise ratio maximization criterion.

[0113] Step 260: Acquire the downlink transmission signal of each user, and perform weighted processing on the downlink transmission signal according to the downlink precoding vector of each user, so as to obtain the downlink transmission signal corresponding to each downlink transmission beam.

[0114] In an embodiment of the present invention, communication configuration information is obtained, satellite ephemeris information and beam configuration information of the communication configuration information are extracted, and the Doppler frequency shift difference and propagation delay difference between each two beam centers are determined according to the downlink carrier frequency, beam center position and satellite ephemeris information of the beam configuration information. The average interference power leakage coefficient of different users on the scheduled subcarriers is determined based on the communication configuration information, each Doppler frequency shift difference and each propagation delay difference. The average channel power and array response vector of the corresponding user are determined according to the communication configuration information. Based on the average signal-to-leakage-to-noise ratio maximization criterion, the downlink precoding vector of each user is determined based on the average interference power leakage coefficient, the average channel power and the array response vector. The downlink transmission signal of each downlink user is obtained, and the downlink transmission signal is weighted according to the downlink precoding vector of each user, thereby obtaining the downlink transmission signal corresponding to each downlink transmission beam. The embodiment of the present invention can solve the asynchronous interference problem between different users in a mobile phone direct-connected satellite communication system.

[0115] Furthermore, based on the above embodiments of the invention, the method further includes normalizing the Doppler frequency shift differences and propagation delay differences according to the subcarrier spacing and sampling interval of the beam configuration information.

[0116] Specifically, the subcarrier spacing and propagation delay in the beam configuration information can be extracted, and the Doppler frequency shift difference and propagation delay difference between each two beam centers can be normalized by the subcarrier spacing and propagation delay. The normalization process can be achieved in the following way: the ratio of the Doppler frequency shift difference to the subcarrier spacing can be used as the normalized Doppler frequency shift difference, and the ratio of the propagation delay difference to the sampling interval can be used as the normalized propagation delay difference.

[0117] Furthermore, based on the above-mentioned embodiment of the invention, the average interference power leakage coefficient of different users on the scheduled subcarriers is determined based on the communication configuration information, each Doppler frequency shift difference, and each propagation delay difference, including:

[0118] Extracting subcarrier spacing, sampling interval, and number of subcarriers from the beam configuration information;

[0119] Determine, based on the subcarrier spacing, sampling interval, number of subcarriers, Doppler frequency shift differences, and propagation delay differences, a power leakage coefficient of each user in other downlink beams in each downlink transmit beam on each scheduled subcarrier to each subcarrier scheduled by each user in the current downlink beam in each downlink transmit beam;

[0120] The sum of the power leakage coefficients of all subcarriers scheduled by all users in the current downlink beam is determined, and the ratio of the sum to the total number of subcarriers of all subcarriers scheduled by all users in the current downlink beam is used as the average interference power leakage coefficient.

[0121] In an embodiment of the present invention, the subcarrier spacing, sampling interval and number of subcarriers included in the beam configuration information can be extracted, and the power leakage coefficient of each subcarrier scheduled by each user in other downlink transmission beams in the downlink transmission beam to each subcarrier scheduled by each user in the current downlink beam can be determined by taking into account the subcarrier spacing, sampling interval, number of subcarriers, various Doppler frequency shift differences and various propagation delay differences. The sum of the power leakage coefficients of all subcarriers scheduled by all users in the current downlink beam is calculated, and the ratio of the sum to the total number of subcarriers of all subcarriers scheduled by all users in the current downlink beam is used as the average interference power leakage coefficient.

[0122] Different systems may have different power coefficient calculation formulas. This embodiment provides an exemplary calculation formula. Based on the above-mentioned embodiment of the invention, the power leakage coefficient calculation formula for determining the power leakage coefficient of each user in other downlink transmit beams in the downlink transmit beam on each scheduled subcarrier to each subcarrier scheduled by each user in the current downlink transmit beam in the downlink transmit beam includes at least:

[0123]

[0124] in, Indicates the scheduling subcarrier of user u in other downlink beam i The power leakage coefficient of the signal of user n scheduled subcarrier r in the current downlink beam k due to frequency asynchrony and time asynchrony is N cp Indicates the cyclic prefix length, N sc Indicates the number of subcarriers, Indicates subcarrier Subcarrier spacing with subcarrier r, ε f =Δf d / Δf represents the normalized frequency offset between user u in other downlink beam i and user n in the current downlink beam k relative to the subcarrier spacing, ε τ =Δτ / T srepresents the normalized timing offset between user u in other downlink beam i and user n in the current downlink beam k relative to the sampling interval, Δf d represents the Doppler frequency shift difference, Δτ represents the propagation delay difference, T s represents the sampling interval, and Δf represents the subcarrier spacing.

[0125] Figure 4 This is a flowchart of another downlink precoding method provided according to an embodiment of the present invention. This embodiment of the present invention is a refinement of the above-mentioned embodiment of the invention, and describes the process of determining the average channel power and the downlink precoding vector. Figure 4 The method provided in the embodiment of the present invention specifically includes the following steps:

[0126] Step 310: Acquire communication configuration information, and determine average interference power leakage coefficients of different users on the scheduled subcarriers according to the communication configuration information.

[0127] Step 320: Extract satellite ephemeris information and user location of the communication configuration information.

[0128] In the embodiment of the present invention, satellite ephemeris information and user location can be extracted from the communication configuration information.

[0129] Step 330: Determine the average channel power of each user on the scheduled subcarrier according to the position of each user and the satellite position in the satellite ephemeris information.

[0130] Specifically, the satellite position in the ephemeris information can be extracted, and the position distance between the satellite position and the user position can be determined for each user based on the corresponding user position and satellite position. The free space loss and other losses of the downlink signal of each user can be determined based on the distance information. For each user, the free space loss, other losses and position distance are combined to determine the average channel power of each user on its scheduled subcarrier through the free space communication distance equation.

[0131] For example, the distance between the satellite and the user can be determined based on the user position and the satellite position, and the distance can be substituted into the free space loss formula to determine the link loss L of user k. k , the free space loss formula can include: L k =(4πd k / λ) 2 , and then determine the average channel power on each user's subcarrier by the following formula, β k =G sat *G ut *M*L k , where L k It can represent the path loss, M can represent the number of antennas, Gsat It can represent the satellite side antenna gain and G ut It can represent the user side antenna gain, wherein the satellite side antenna gain and the user side antenna gain can be queried in the true element power pattern based on the user's spatial angle, and the ratio of the average channel power of each user to the number of subcarriers of the subcarriers scheduled by the user can be used as the average channel power of the user on the subcarriers scheduled by the user.

[0132] Step 340: Extract satellite ephemeris information and user positions from the communication configuration information; determine the array response vector of each user on the satellite side according to the user position and the satellite position in the satellite ephemeris information.

[0133] Specifically, the satellite position can be determined according to the satellite ephemeris information, the satellite side spatial angle corresponding to each user can be determined according to the satellite position and the user position, and the array response vector of each user on the satellite side can be determined according to the spatial angle.

[0134] For example, the spatial angle of the kth downlink transmission beam of user n on the satellite side is The AOD angle of the kth downlink transmission beam of user n is recorded as in, The above formula can be used to determine the corresponding satellite-side spatial angle based on the AOD angle of each user. The array response vector on the satellite side can be determined based on the spatial angle of the k-th downlink transmission beam of each user n by the following formula:

[0135]

[0136] in, λ is the carrier wavelength, n v is the number of array elements along the v axis, d v is the spacing of the antennas along the v-axis, v∈{x,y}.

[0137] Step 350: Substitute the average channel power, average interference power leakage coefficient, and array response vector on each subcarrier into a preset average signal-to-leakage-and-noise ratio determination formula, wherein the preset average signal-to-leakage-and-noise ratio determination formula at least includes a correspondence between the average signal-to-leakage-and-noise ratio and the downlink precoding vector.

[0138] In an embodiment of the present invention, the average channel power, array response vector, and average interference power leakage coefficient on each subcarrier can be substituted into a preset average signal-to-leakage-and-noise ratio determination formula. The preset average signal-to-leakage-and-noise ratio determination formula is calculated by the average value of the ratio of the sum of the average channel power, interference power, and noise power on each subcarrier. The interference power can be determined by the average interference power leakage coefficient, and the noise power can be represented by a downlink precoding vector. The interference power and the noise power can be adjusted to maximize the average signal-to-leakage-and-noise ratio.

[0139] Step 360: When the average signal-to-leakage-and-noise ratio takes the maximum value, determine the downlink precoding vector.

[0140] Specifically, the interference power corresponding to the average interference power leakage coefficient in the preset average signal-to-leakage-and-noise ratio determination formula and the background noise power formed by the downlink precoding vector can be adjusted so that the preset average signal-to-leakage-and-noise ratio determination formula has a maximum value, and the downlink precoding vector can be obtained when the value of the average signal-to-leakage-and-noise ratio in the preset average signal-to-leakage-and-noise ratio determination formula is maximized.

[0141] Step 370: Acquire the downlink transmission signal of each user, and perform weighted processing on the downlink transmission signal according to the downlink precoding vector of each user, so as to obtain the downlink transmission signal corresponding to each downlink transmission beam.

[0142] In an embodiment of the present invention, communication configuration information is obtained, and the average interference power leakage coefficient of each user on the scheduled subcarrier is determined according to the communication configuration information. The satellite ephemeris information and user position in the communication configuration information are extracted, and the average channel power and array response vector of each user on the scheduled subcarrier are determined according to the user position and the satellite position of the satellite ephemeris information. The average channel power, array response vector, and average interference power leakage coefficient on each subcarrier are substituted into a preset average signal-to-leakage-and-noise ratio determination formula. The corresponding downlink precoding vector is obtained while maximizing the average signal-to-leakage-and-noise ratio. The downlink transmission signal of each downlink user is obtained, and the downlink transmission signal is weighted according to the downlink precoding vector of each user, thereby obtaining the downlink transmission signal corresponding to each downlink transmission beam. The embodiment of the present invention can solve the problem of asynchronous interference between different users in a mobile phone direct-connect satellite communication system and improve the downlink transmission performance of a multi-beam satellite mobile communication system.

[0143] Furthermore, based on the above embodiments of the invention, the preset average signal-to-leakage-to-noise ratio determination formula at least includes:

[0144]

[0145] Among them, β k,nrepresents the average channel power of user n on each scheduled subcarrier in the current downlink beam k, is the array response vector of user n on the satellite side in downlink beam k, represents the average transmit power of user n on each scheduled subcarrier in the current downlink beam k of the downlink transmit beam, σ k,n represents the average noise variance of each subcarrier scheduled by user n in the current downlink beam k in the downlink transmission beam, B dl represents the beamforming matrix of the downlink transmit beam,

[0146] M is the number of satellite-side antennas, K is the number of downlink beams, is the beamforming vector of downlink beam k, represents the beam selection matrix of user n in downlink beam k, N v The number of beams N is selected to be retained when calculating the precoding vector for user n in downlink beam k. v ≤K, V k,n The ζth column of That is, the nth ζ A column vector with 1 elements and the rest 0 elements, indicating that the nth ζ beams, i.e. retain B dl nth ζ List, represents the downlink precoding vector of user n in the current downlink beam k, represents the average channel power leaked from user n in the current downlink beam k to other users in other downlink beams, It represents the average interference power coefficient of the signals on all scheduled subcarriers of user n in the current downlink beam k leaking to all scheduled subcarriers of user u in other downlink beam i due to frequency asynchrony and time asynchrony.

[0147] On the basis of the above-mentioned embodiment of the invention, it also includes: for each current downlink beam, calculating the spatial angle difference between the current downlink beam and all other beams, and selecting the downlink beam whose spatial angle difference is less than or equal to the spatial angle distance threshold according to the preset spatial angle distance threshold, and constructing the beam selection matrix of user n in the current downlink beam k based on the selected downlink beam The constructed beam selection matrix can reduce the precoding vector from K dimensions to N dimensions. v dimension, and N v ≤K. Furthermore, the dimension of the matrix inversion in the precoding vector calculation process is also reduced from K to N. v dimension, thereby reducing the computational complexity of the precoding vector.

[0148] Specifically, when calculating the downlink precoding vector of user n in downlink beam k, the spatial angle distance between each downlink transmit beam and the current downlink beam of the user is first calculated. When the distance is greater than a certain threshold, the influence of these downlink transmit beams with a spatial angle distance greater than the threshold is ignored, and only downlink transmit beams with a closer spatial angle distance are selected to participate in the calculation of the downlink precoding vector of the current downlink beam k of user n. The threshold is configured according to the actual system.

[0149] Based on the above embodiment of the invention, the downlink precoding vectors of the user on different subcarriers are the same.

[0150] In the embodiment of the present invention, the downlink precoding vectors of each user on different subcarriers are the same, that is, the users all use the same downlink precoding vector on their scheduled frequency bands.

[0151] In an exemplary embodiment, see Figure 5 , considering that downlink transmission precoding is implemented for each user at the downlink transmitting end on the satellite side, the downlink frequency domain received signal of user n in beam k on the rth subcarrier can be expressed as

[0152]

[0153] in, is the beamforming matrix of K downlink beams, is the transmit power of the rth subcarrier allocated to user n in beam i, is the downlink transmission precoding vector of the rth subcarrier of user n in beam i with normalized power, satisfying ||p i,n,r ||=1, is the transmitted signal of the rth subcarrier of user n in beam i, with a mean of 0 and a variance of 1. It is the sum of equivalent noise and interference from different subcarriers in other beams.

[0154] Average Signal-to-Leakage-and-Noise Ratio (SLNR) is a convenient and efficient criterion for measuring the performance of downlink multi-user Multiple-Input Multiple-Output (MIMO) transmission. However, precoding based on SLNR requires obtaining the instantaneous channels of all users on the satellite side. However, in actual LEO satellite communication systems, due to inherent channel characteristics, such as large propagation delay and Doppler shift, it is extremely difficult to obtain instantaneous channel state information (CSI) at the transmitter. Compared with instantaneous CSI, statistical CSI remains unchanged over a longer time interval and is easier to be obtained by the transmitter. Therefore, precoding based on statistical CSI can effectively solve the problem of instantaneous CSI acquisition. Define the average signal-to-leakage-and-noise ratio (Average

[0155] Signal-to-Leakage-and-Noise Ratio (ASLNR) is:

[0156]

[0157] Among them, the numerator and denominator are the average power of the signal and the average power of the leakage plus noise respectively. is the downlink SNR of user n in beam k at the rth subcarrier, represents the average power of the signal of user n in beam k leaking to different subcarriers in other beams, Power leakage coefficient, see formula (19) for details.

[0158] If the ASLNR on each subcarrier is maximized, the precoding vector needs to be calculated once on each subcarrier, which is extremely computationally complex. From the expression of the power leakage coefficient, it can be seen that the leakage power of each subcarrier is large only in the adjacent subcarriers, and the power leaked to the subcarriers far away is almost zero. Consider the leakage of all subcarriers of user n in beam k to user u in beam i. The total power of the subcarriers It can be found that the asynchronous interference caused by time asynchrony and frequency asynchrony only has a greater impact on the edge subcarriers of the same-frequency users and adjacent frequency band users. Therefore, we can use the average leakage power coefficient replace remember

[0159]

[0160] is the average power coefficient of the signal leakage from all subcarriers of user n in beam k to each subcarrier of user u in beam i, where |Φi,u | represents the set Φ i,u The number of elements in is the number of subcarriers occupied by user u in beam i. At the same time, β is ignored. k,n,r Neutron carrier index, denoted by β k,n represents the average channel power on each subcarrier. Then the average ASLNR of the user on each subcarrier scheduled in the frequency domain is

[0161]

[0162] in, is the average transmit power on different subcarriers, is the average noise variance on different subcarriers, It represents the average power of the signal of user n in beam k leaking to users of different frequencies in other beams.

[0163] Make ASLNR′ k,n The maximized precoding vector for user n in beam k is:

[0164]

[0165] in, In order to make The power normalization factor.

[0166] Since the amount of power leakage from user n in beam k to the user channel in beam i is related to the spatial angular distance between beam k and beam i, the greater the spatial distance, the smaller the leakage power. Therefore, when considering the beam domain channel response vector, the influence of beams with a longer spatial distance can be ignored. Let represents the beam selection matrix of user n in downlink beam k, N v The number of beams N is selected to be retained when calculating the precoding vector for user n in downlink beam k. v ≤K, V k,n The i-th column of That is, the nth i A column vector with 1 elements and the rest 0 elements, indicating that the nth i beams, i.e. retain B dl nth i List, represents the downlink precoding vector of user n in the current downlink beam k in the downlink transmit beam, then

[0167]

[0168] in, At this time, the precoding vector is

[0169]

[0170] in, In order to make The power normalization factor of

[0171] Among them, β k,n represents the average channel power of user n on each scheduled subcarrier in the current downlink beam k in the downlink transmission beam, β i,n represents the average channel power of user n in other downlink beam i on each scheduled subcarrier in the downlink transmit beam, is the array response vector of user n on the satellite side in the current downlink beam k, represents the average transmit power of user n on each scheduled subcarrier in the current downlink beam k of the downlink transmit beam, σ k,n represents the average noise variance of each subcarrier scheduled by user n in the current downlink beam k in the downlink transmission beam, B dl represents the beamforming matrix of the downlink transmit beam, M is the number of satellite-side antennas, K is the number of downlink beams, is the beamforming vector of the current downlink beam k, represents the beam selection matrix of user n in the current downlink beam k, N v The number of beams N is selected to be retained when calculating the precoding vector for user n in the current downlink beam k. v ≤K, V k,n The ζth column of For nth ζ A column vector with 1 elements and the rest 0 elements. Indicates selection of nth ζ beams, i.e. retain B dl nth ζ List, represents the downlink precoding vector of user n in the current downlink beam k, It represents the average channel power of user n in the current downlink beam k leaked to other user u in other downlink beam i in the downlink transmission beam, It represents the average interference power coefficient of the signal on all scheduled subcarriers of user n in the current downlink beam k leaking to all scheduled subcarriers of user u in other downlink beam i due to frequency asynchrony and time asynchrony, i≠k. In general, N v are much smaller than K, so the computational complexity of the precoding vector will be significantly reduced, and when the number of beams K is larger, the computational complexity of the proposed method will be reduced more significantly.

[0172] The satellite orbit altitude is 350 km. A 32×32 uniform planar array antenna with half-wavelength element spacing is deployed on the satellite side. User terminals are equipped with single omnidirectional antennas. Terminal transmit power is based on that of commercial mobile phones. The simulation channel uses the 3GPP NTN channel model. Parameters such as multipath number, path loss, shadow fading, and Ricean factor are calculated based on the scenario, with the first path being the Loss of Sight (LOS) path. The carrier frequency is 2 GHz, the bandwidth is 10 MHz, and there are 16 beams, with four users per beam. To verify the impact of asynchronous satellite-side interference on system performance at different beam distances, four different beam coverage schemes are shown in Figures 6(a), 6(b), 6(c), and 6(d). In Figure 6, the large circle represents the satellite coverage area, the small circle represents the downlink beam coverage area, and the black dots within the small circles represent the user locations within the downlink beam. Users are randomly distributed within the 3 dB beam range.

[0173] Figures 7(a), 7(b), 7(c), and 7(d) compare the downlink sum rate performance using different transmission schemes. The solid star-shaped lines in the figure represent the downlink sum rate performance curve based on maximized ASLNR precoding under asynchronous interference, while the hollow circle lines represent the downlink sum rate performance curve for multi-beam transmission without precoding under asynchronous interference. As can be seen in Figure 7, compared with the scheme without precoding, the downlink sum rate performance using maximized ASLNR precoding under asynchronous interference is significantly improved. When the satellite downlink transmit power is 30dBW, the performance of beam coverage scheme (a) improves by approximately 141%, and the performance of beam coverage scheme (d) improves by approximately 48%.

[0174] Figure 8 This is a schematic diagram of the structure of a downlink precoding device provided according to an embodiment of the present invention. Figure 8 The downlink precoding device may include a power leakage coefficient calculation module, a downlink precoding calculation module for suppressing asynchronous interference, and a downlink transmission weighting module, see Figure 9The downlink precoding device can obtain communication configuration information such as satellite position, number of users and position of each user, downlink time-frequency resource scheduling, correspondence between beams, number of beams and spatial angle of each beam from the configuration module; the power leakage coefficient calculation module calculates the Doppler frequency shift deviation and propagation delay difference between all beam center points, and calculates the power leakage coefficient of each user on each subcarrier of each user in other beams due to frequency asynchrony and time asynchrony based on the Doppler frequency shift deviation and propagation delay difference between the beam center point of each user and the center points of other beams, and calculates the average interference power leakage coefficient of each user on the scheduled subcarrier; the downlink precoding calculation module for suppressing asynchronous interference obtains the average channel power of each user calculated based on the satellite and user position, and calculates the downlink precoding vector of each user according to the average signal-to-leakage-to-noise ratio maximization criterion; the downlink transmission weighting module uses the downlink precoding vector to weight the transmission signal of each downlink user to obtain the downlink transmission signal corresponding to each downlink transmission beam.

[0175] Figure 10 This is a schematic diagram of the structure of a downlink precoding device provided according to an embodiment of the present invention. Figure 10 As shown, the device includes:

[0176] The power leakage coefficient determination module 410 is configured to obtain communication configuration information and determine the average interference power leakage coefficients of different users on the scheduled subcarriers according to the communication configuration information.

[0177] The channel parameter determination module 420 is configured to determine an average channel power and an array response vector for each user based on the communication configuration information.

[0178] The precoding determination module 430 is configured to determine a downlink precoding vector for each user according to the average interference power leakage coefficient, the average channel power, and the array response vector in accordance with a criterion of maximizing an average signal-to-leakage-and-noise ratio.

[0179] The signal generating module 440 is configured to obtain a downlink transmission signal of each user, and perform weighted processing on the downlink transmission signal according to the downlink precoding vector of each user, thereby obtaining a downlink transmission signal corresponding to each downlink transmission beam.

[0180] In an embodiment of the present invention, a power leakage coefficient determination module obtains communication configuration information, determines the average interference power leakage coefficient of different users on their scheduled subcarriers according to the communication configuration information, and a channel parameter determination module determines the parallel channel power and array response vector of each user according to the communication configuration information. A precoding determination module determines the downlink precoding vector of each user based on the average interference power leakage coefficient, array response vector, and average channel power based on the average signal-to-leakage-to-noise ratio maximization criterion. A signal generation module obtains the downlink transmission signal of each downlink user and performs weighted processing on the downlink transmission signal according to the downlink precoding vector of each user, thereby obtaining the downlink transmission signal corresponding to each downlink transmission beam. The embodiment of the present invention can solve the problem of asynchronous interference between different users in a mobile phone direct-connected satellite communication system and improve the downlink transmission performance of a multi-beam satellite mobile communication system.

[0181] The downlink precoding device provided in the embodiment of the present invention can execute the downlink precoding method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0182] Figure 11 : is a structural diagram of an electronic device that implements the downlink precoding method of an embodiment of the present invention. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are only examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0183] like Figure 11 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., which is communicatively connected to the at least one processor 11. The memory stores a computer program that can be executed by the at least one processor. The processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 into the random access memory (RAM) 13. Various programs and data required for the operation of the electronic device 10 can also be stored in the RAM 13. The processor 11, ROM 12, and RAM 13 are connected to each other via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0184] Multiple components in the electronic device 10 are connected to the I / O interface 15, including an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a magnetic disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices via a computer network such as the Internet and / or various telecommunication networks.

[0185] The processor 11 may be any general-purpose and / or specialized processing component with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various specialized artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as the downlink precoding method.

[0186] In some embodiments, the downlink precoding method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the downlink precoding method described above may be performed. Alternatively, in other embodiments, processor 11 may be configured to perform the downlink precoding method in any other appropriate manner (e.g., via firmware).

[0187] Various embodiments of the systems and techniques described herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), system-on-chip systems (SOCs), programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include being implemented in one or more computer programs that are executable and / or interpreted on a programmable system that includes at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0188] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when the computer program is executed by the processor, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The computer program may be executed entirely on the machine, partially on the machine, as a stand-alone software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0189] In the context of the present invention, computer-readable storage media can be tangible media that can contain or store a computer program for use with an instruction execution system, device or equipment or used in combination with an instruction execution system, device or equipment. Computer-readable storage media can include but are not limited to electronic, magnetic, optical, electromagnetic, infrared or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, computer-readable storage media can be machine-readable signal media. More specific examples of machine-readable storage media can include electrical connections based on one or more lines, portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memory), optical fibers, portable compact disk read-only memories (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0190] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0191] The systems and techniques described herein can be implemented in a computing system that includes back-end components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes front-end components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such back-end components, middleware components, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0192] A computing system may include clients and servers. The clients and servers are typically remote from each other and typically interact via a communication network. This client-server relationship arises through computer programs running on the respective computers, creating a client-server relationship. The server may be a cloud server, also known as a cloud computing server or cloud host. This server is a hosting product within the cloud computing service ecosystem that addresses the management difficulties and limited scalability of traditional physical hosting and VPS services.

[0193] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0194] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A downlink precoding method, characterized in that: Applied to a sending end, the method includes: Acquire communication configuration information, and determine average interference power leakage coefficients of different users on the scheduled subcarriers based on the communication configuration information; Determining an average channel power and an array response vector for each of the users based on the communication configuration information; Determine a downlink precoding vector for each user according to the average interference power leakage coefficient, the average channel power and the array response vector according to an average signal-to-leakage-to-noise ratio maximization criterion; A downlink transmission signal of each of the users is obtained, and weighted processing is performed on the downlink transmission signal according to the downlink precoding vector of each of the users, thereby obtaining a downlink transmission signal corresponding to each downlink transmission beam.

2. The method according to claim 1, characterized in that The determining, according to the communication configuration information, an average interference power leakage coefficient of different users on the scheduled subcarriers includes: Extracting satellite ephemeris information and beam configuration information from the communication configuration information; Determine the Doppler frequency shift difference and propagation delay difference between every two beam centers according to the satellite ephemeris information and the downlink carrier frequency and beam center position in the beam configuration information; The average interference power leakage coefficients of different users on the scheduled subcarriers are determined based on the communication configuration information, the Doppler frequency shift differences, and the propagation delay differences.

3. The method according to claim 2, characterized in that The determining, based on the communication configuration information, each of the Doppler frequency shift differences, and each of the propagation delay differences, an average interference power leakage coefficient of different users on the scheduled subcarriers includes: Extracting the subcarrier spacing, sampling interval, and number of subcarriers from the beam configuration information; Determine, based on the subcarrier spacing, the sampling interval, the number of subcarriers, the Doppler frequency shift differences, and the propagation delay differences, a power leakage coefficient of each user in other downlink beams in each downlink transmit beam on each scheduled subcarrier to each subcarrier scheduled by each user in the current downlink beam in each downlink transmit beam; Determine the sum of the power leakage coefficients of all subcarriers scheduled by all users in the current downlink beam, and use the ratio of the sum to the total number of subcarriers of all subcarriers scheduled by all users in the current downlink beam as the average interference power leakage coefficient.

4. The method according to claim 1, characterized in that The determining the array response vector of each user based on the communication configuration information includes: Extracting satellite ephemeris information and user location of the communication configuration information; An array response vector of each user on the satellite side and an average channel power of each user on the scheduled subcarrier are determined according to the position of each user and the satellite position in the satellite ephemeris information.

5. The method according to claim 1, characterized in that: The determining, according to the average interference power leakage coefficient, the average channel power, and the array response vector and in accordance with an average signal-to-leakage-and-noise ratio maximization criterion, of the downlink precoding vector of each user includes: Substituting the average channel power on each subcarrier, the average interference power leakage coefficient, and the array response vector into a preset average signal-to-leakage-and-noise ratio determination formula, wherein the preset average signal-to-leakage-and-noise ratio determination formula at least includes a correspondence between the average signal-to-leakage-and-noise ratio and the downlink precoding vector; When the average signal-to-leakage-and-noise ratio takes a maximum value, the downlink precoding vector is determined.

6. The method according to claim 5, characterized in that The preset average signal-to-leakage-to-noise ratio determination formula at least includes: Among them, β k,n represents the average channel power of user n in the current downlink beam k on each scheduled subcarrier in the downlink transmission beam, β i,n represents the average channel power of user n in other downlink beams i in the downlink transmit beam on each scheduled subcarrier, is the array response vector of user n on the satellite side in the current downlink beam k, represents the average transmit power of user n in each scheduled subcarrier in the current downlink beam k of the downlink transmit beam, σ k,n represents the average noise variance of each subcarrier scheduled by user n in the current downlink beam k in the downlink transmission beam, B dl represents the beamforming matrix of the downlink transmit beam, M is the number of satellite-side antennas, K is the number of downlink beams, is the beamforming vector of the current downlink beam k, represents the beam selection matrix of user n in the current downlink beam k, N v The number of beams selected to be retained when calculating the precoding vector of user n in the current downlink beam k, N v ≤K, V k,n The ζth column of For nth ζ A column vector with 1 elements and the rest 0 elements. represents the downlink precoding vector of user n in the current downlink beam k, represents the average channel power of user n in the current downlink beam k leaked to other users u in other downlink beams i in the downlink transmit beam, It represents the average interference power coefficient of the signals on all scheduled subcarriers of user n in the current downlink beam k leaking to all scheduled subcarriers of user u in the other downlink beam i due to frequency asynchrony and time asynchrony, i≠k.

7. The method according to claim 6, characterized in that Before substituting the average channel power on each subcarrier, the average interference power leakage coefficient, and the array response vector into a preset average signal-to-leakage-and-noise ratio determination formula, the method further includes: For each of the current downlink beams, the spatial angle difference between the current downlink beam and all other beams is calculated, and according to a preset spatial angle distance threshold, a downlink beam whose spatial angle difference is less than or equal to the spatial angle distance threshold is selected, and a beam selection matrix for users in the current downlink beam is constructed based on the selected downlink beam.

8. A downlink precoding device, characterized in that: Applied to a transmitting end, the device includes: A power leakage coefficient determination module is used to obtain communication configuration information and determine the average interference power leakage coefficient of different users on the scheduled subcarriers according to the communication configuration information; a channel power determination module, configured to determine an average channel power and an array response vector for each of the users based on the communication configuration information; a precoding determination module, configured to determine a downlink precoding vector for each user according to a criterion of maximizing an average signal-to-leakage-and-noise ratio based on the average interference power leakage coefficient, the average channel power, and the array response vector; The signal generating module is used to obtain the downlink transmission signal of each user, and perform weighted processing on the downlink transmission signal according to the downlink precoding vector of each user, so as to obtain the downlink transmission signal corresponding to each downlink transmission beam.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can perform a downlink precoding method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement a downlink precoding method according to any one of claims 1 to 7 when executed.

11. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is executed by a processor, the computer program implements a downlink precoding according to any one of claims 1 to 7.

Images